s TIONS: $4 for one year (4 issues), $8 for two years (8 issues), back iss each (numbers 5— ntly available), send check or money order paya ris Hansen.

E.U.B.LlS-H.n: Chris Hansen, 1226, New Yo 0159. * * * * * * * * * * EDIT_QR: Dallas Lankford, P. O. Box 614 LA 71272—0018. * * * * * * * * * * CONTRIBUTING EDITOR: S Y, P. O. Box C- , minson, NJ 08077. * * * *

The 0 pressed in The Hollow State Newsletter belong ividual ontributors and do not necessarily reflect those of the editors or publis er.

1 EDITOR’S CORNER

The Hollow State Newsletter (hereafter abbreviated HSN), founded by T. J. Skip Arey, WB2GHA, was originally called The R390 Users Group, A Newsletter For URR Users. The first four issues appeared in the spring, summer, fall, and winter of 1983. Because those back issues have been sold out, your publisher and editor have considered the options of reprinting the original issues, or selecting parts which seem to be of lasting value and interest. We have chosen the latter. Previous issues contained what might be regarded as incorrect or misleading information, which we will seek to correct. However, it should be emphasized that those errors were not deliberate, but rather the well-intentioned efforts of subscribers to share their information and knowledge. Also, please bear in mind that one person’s “correct” may be another person’s “incorrect,” or even a matter of personal opinion. Because of our six page limit per reprint, it is unfortunate that some contributions from HSN 1—4 could not be included. Prices, such as for tubes below, have been updated, but it is still prudent to write for current prices and availability.

SHORT CONTRIBUTIONS

R-390A TUBES: The 3TF7 tube near the front of the R-390A IF subchassis (usually denoted RT-510 on the subchassis) was originally thought to be generally unavailable. Although expensive at $10—15 each, several suppliers are now known, and current issues of HSN keep subscribers informed of prices and availability. Newly manufactured 3TF7’s are available again at $39 (!). The 26Z5W tube was also thought to be generally unavailable, but again several suppliers are now known, currently about $5 each. All other R—390A 1 tubes are currently available for about $2 each. (Dallas Lankford)

R—390A AUDIO MOD: For increased audio gain, place a jumper from pin 6 to pin 8 on 1 the rear terminal strip. (Jim Herkimer) Sometimes there may be no increased audio gain

This document was produced with an IBM PC AT and a Cordata LP—300 laser printer using software developed by Personal TEX, Inc.

with the previous mod. In that case, try jumping pins 1, 2, 3, and 4 together. (Walter Schivo)

TOOLS: A neophyte who doesn’t recognize that all of the set screws and socket head screws throughout an R—390A are multiple spline (also known as fluted Bristol) may strip one or more of these next to impossible obtain items. The military manuals call for a fluted #8 Bristo [sic] wrench, which is not how the wrench is described in current catalogs. The military also seems to have misspelled Bristol throughout its manuals. The equivalent wrench in current terminology is a 0.096″ Bristol 6-flute wrench (also called a screwdriver). Xcelite makes a good insertable tip (model 99-66) for use with various handles the model 99-1 regular handle is suitable). I would also recommend the 4″ extension model 99X5 which is especially useful for removing some front panel knobs. One of my R–390A’s inc uded a few sockets which required the 0.111″ tip (model 99-67). If you do much work on military equipment it is worthwhile to get a complete set of spline wrenches, such as the Xcelite 99-PS-60. General Cement also makes a set of small, L-shaped, spline key wrenches, GC catalog # 5070 (they don’t sell directly to individuals, so you will probably have to order them through your local electronics distributor . You will also need good the RF subchassis, you will require a long blade 6—10″) #2 Phillips screwdriver, such as Sears # 9 41296 A WF. (Even with a long blade Phillips, to get its tip onto one of the RF subchassis rear green quick release screws you will have to remove many, but not all, screws from the rear panel, loosen some of the remaining rear panel screws, and tilt the top of the rear panel backward slightly.) I have found the Sears Craftsman # 9 43441 10piece combination ignition wrench set very useful for the many small nuts in the R—390A. (Dallas Lankford)

DETACHED FERRITE CORES: Has one of your ferrite cores ever fallen off its rod? If it does, remove the bracket by taking out the two Phillips head screws, remove the spline socket head screw with attached wire spring, put a small amount of epoxy glue on the end of the spring which was préviously inserted into the the ferrite core, reinsert that end into the ferrite core, wait until the glue sets, remove the ferrite core, re-assemble, and re-peak that coil. (Wayne Heinen) [If glue accidentally gets onto the inside wall of the coil form, or the wire spring does not re-insert fully, you may have a mess. So you may wish to use a wood toothpick to remove the ferrite core (be gentle!) and do the gluing externally. Fast drying epoxy glue sometimes has disadvantages. The wire spring is generally coated with old glue and embedded ferrite so that it can barely be reinserted. When glue is applied, it may be impossible to reinsert the spring completely, and with fa..st drying glue the mistake may be permanent. I suggest either completely removing the old glue from the wire spring, or at least cutting some small notches so that surplus glue can be expelled from the hole as the wire spring is reinserted. Ed.]

R—390A TUBE SHIELDS: All of the tube shields may be removed for improved cooling performance and tube life. I have no problems here running 300 watts. (Chris Hansen) One manual states that all tube shields may be removed except the voltage regulator, PTO, BFO, RF amp, and three mixer tubes. But I have temporarily removed them all, too, with no noticeable problems. (Dallas Lankford)

R—390A SSE MOD: H. Cornelius has written that a major reason for poor SSB performance is inadequate AGC voltage which fails to keep SSB signal levels at the diode detector below the BFO signal level, thus causing severe distortion on strong signals. This mod increases AGC voltage and shortens attack time which frequently improves SSB and RTTY performance. (1) remove the IF subchassis, (2) remove R-545 (100K), (3) install a diode (IN914/1N34/1N60/1N4148) in place of R546 (180K) with the cathode (band) facing the tube socket, (4) replace R547 (220K) with a 10K 1/2W, (5) examine R504, if it is not 560 ohms, replace it with that value (this was a production change in some models), (6) replace the IF subchassis, (7) re-align the BANDWIDTH and BFO PITCH

Selected Reprints From Numbers 1—4 (1986) Page 3

knobs. (anonymous) [This mod does not improve the SSB on some early R—390A’s. Before O you try the mod, remove the IF transformer shields and examine the Q-spoiling resistors inside the shields which are in parallel with the inputs and outputs of the IF transformer coils. If the resistors in the two T501/T502 cans are 39K, and in T503 is 68K, the mod should work, while if the resistors are 47K and 82K respectively, the mod probably will not work. Replacing the 47K and 82K resistors with 39K and 68K respectively did not help in my experience, suggesting that early IF transformer coils may have different turns ratios and/or couplings from later models. A before—after sketch of this mod is in HSN 10. Ed.]

/URR MANUALS: The following manuals were available from the U. S. Army A. G. Publication Center, 1655 Woodson Road, St. Louis, MO 63114. Write for current prices.

R—389: (A) technical manual, TM-11-855, (B) TM-11-5820-36-24P (see note qi below , changes 3, 5, and 6, TM-11-5820-36-24P, C3, 5, and 6, (2) R—390A: (A) Fie And epot Maintenance Manual, TM-11-5820-385-35, (B) Operators Manual, TM-11-5820-385-10, t) Organizational Maintenance Manual, TM-11-5820-385-20, note (iil (D) TM-11-5820-385-34P see note (i) below), (E) TM-11-5820-385-20P (see below), (3) R—392: (A) oper- ators manual, TM-11-5820-334-10, (B) installation and 2n echelon maintenance manual, TM-11-5820-334-20, (C) TM-Il-5820-334-34P (see note (i) below), (D)

20P (see note (i) below), Note (i): direct support and general support maintenance repair o and special tools list. Note (ii): organizational maintenance repair parts and special tools list. The following manuals were available from the Naval Publications and Forms Center, 5801 Tabor Ave., Philadelphia, PA 19120. R—390A: (A) operation and maintenance manual 096-LP-063-2010, (B) change 2/18/72 0967-LP-063-2011, (c-E) -2012, -2013, -2014. o (Phil Bytheway) [Exact titles of manuals above are capitalized in the cases where I could double check them. For the Army R—390A manuals (D) and (E) above, I have the exact titles, but omitted them because those manuals consist mainly of pictures and parts lists, and so are not generally useful. I have an R—390A Navy manual which may be different from above: Operation, Maintenance And Installation Instructions With Parts List, Radio Receiver R-390A/URR, Technical Manual, NAVSHIPS 0967-063-2100, 15 April 1970. Ed.] To obtain manuals through the above sources requires approval of the proponent agency, e.g., Naval Electronics System Command, Technical Publications Branch, and release policies have tightened up considerably. (Bill Neil) [My experiences in 1982 agree with Bill’s. Policies do change, however, so those needing manuals might try again. Handwritten leto ters on cheap notebook paper will probably get no results. A typed letter with a company letterhead and envelope, and a legitimate need for the manual(s) may give good results. Ed.]

o R-390A POWER SUPPLY MOD: If this mod has been done in your R-390A, it deserves your attention. My most recent manual (1970) describes the solid state conversion without a dropping resistor. However, the diodes increase the B+ voltage from about 240 VDC (with the 26Z5W rectifier tubes) to about 270 VDC (with the diodes). [These voltage values are incorrect, and merely reproduce another person’s mistake. Ed.] If a dropping resistor is not used to bring the B+ down to 240 VDC, the 6AK6 line and local AF output tubes will operate beyond their maximum ratings, causing excessive tube failures and 1 possible damage to associated components. So R—390A users should check out their power supply. (Dallas Lankford) [Originally this contribution was much longer, with details about how to convert the power supply to solid state, replacing the 26Z5W tubes with 1000 P IV, 1 1 A or better diodes. This conversion was thought to be needed because 26Z5W tubes were thought to be generally unavailable. I have subsequently unmodified my R—390A’s back to their original condition, and use 26Z5W tubes. However, I have retained a dropping resistor (currently 75 ohms because measurement showed that was about 265 VDC with the 26Z5W’s alone. easurement with the diode mod and no dropping resistor was a whopping 290 VDC. Voltages in an R—390A also depend on the strength of a received signal, and on the FUNCTION switch setting, STAND BY / AGC / MCC / CAL. Manual

B+ and tube pin voltages seem to be for AGC (FUNCTION) with no antenna attached and no signal received. Ed. If you do convert your power supply to solid state, you might O want to use 2000 V, 2 A iodes. The 1000 V, 1 A diodes sometimes go “pop.” (Dick Walser) [This sounds like a good idea. Unfortunately, none of the electronics suppliers in my area can obtain 2000 V, 2 A diodes, even through their gatalogs. The 1000 V, 1 A diodes worked fine in one of my units for two years. Maybe it depends on the brand of

diode. For example, my electrical engineering friends are suspicious of all Radio Shack semiconductors. Ed.]

3-T.E..ZR.UR.P-.QSE: There is one reason why you should not remove and/or modify the 3TF7 tube even if they cost a small fortune. Ballast tubes function as an automatic rheostat which keeps a constant current to the BFO and PTO tube filaments, even if there is a line voltage surge or drop. Unfortunately a simple resistor will not perform this function. (Steve Bohac) [A local ham, who is also a professor of electrical engineering, told me that ballast tube replacement is indeed risky. In some receivers, if the ballast tube is replaced by only a resistor, even turning on or off the lights in your house or apartment can cause a noticable frequency shift, which is certainly undesirable for CW and SSB rece.ption. Despite these potential problems, the high cost of new 3TF7’s and scarcity of reasonably priced surplus 3TF7’s makes substitutes, including less than desirable substitutes, an important topic for R—390(A) users, see the following. Ed.]

3TF7 SUBSTITUTES: The 3TF7 is used a ballast tube in both the R-390 and R-390A, and the following three susbtitutes work for both receivers. (1) Remove the 3TF7 and plug a 42 ohm 5 watt resistor into pins 2 and 7 of the 3TF7 socket. [This is a quick temporary

fix in case you don’t have a spare 3TF7 on

hand. Ed.] (2) Replace V508 and V701 (PTO1 and BFO tubes) with 12BA6’s, remove the 3TF7, and plug a short wire •umper into pins

anonymous)

600—8 OHM KLUDGE: If you are having diffculty getting good audio from an 8 ohm speaker because the government in its infinite wisdom chose another impedance, try a 115 V to 12 V power supply transformer, such as Radio Shack part #273-1385, current price $3.29. Connect the primary (black wires to your receiver and the secondary (red) wires to your 8 ohm speaker. (Skip Arey

UG—421/U: The UG—421/U connector plug, the one for the R—390A balanced antenna inout, is available from Amphenol under the part number KS 16288L2. (Paul Gunn)

BC—453: Some of the fine old tube receivers can be found wanting in the area of IF selectivity. A cheap way of solving this problem is the BC—453. This is a WW—II aircraft receiver which tunes 190—550 khz, and so it can be used as a selective IF for any receiver whose IF is in that frequency range. The R—IIA is a similar receiver which can also be used for this purpose. Both of these receivers are frequently available from Fair Radio for about $15 plus shipping. They are not for the faint of heart, as you will need to construct

2 and 7 of the 3TF7 socket. This mod draws . less current than the original circuit, which may have a beneficial effect on PTO and BFO frequency stability. Ed.] (3) Build a triac regulator, such as the one at right, which can be plugged into pins 2 and 7 of the 3TF7 socket. The diodes are 100 V, 0.5 A, and the zener is 14—15 V. Ground the regulator 15 v circuit to one of the tube mounting screws. Zener Adjust the pot for 12.6 VDC at .3TF7 pin 7.

a power supply for 12, 24, and 250 VDC. Once you get this little box cooking you can either inductively couple it to your main receiver or use a piece of coax with the shield

Selected Reprints From Numbers 1—4 (1986) Page 5

connected to the case of both the BC—453 and your receiver, and one end of the center conductor of the coax connected the antenna post of the BC—453 with the other end of the center conductor wrapped a few times around the plate pin of the first IF amplifier tube. You will have to experiment with the degree of coupling between the two. Some folks say the BC—453 works best with the plungers of its IF cans turned all the way out. More information on the Q5er, as it is called, can be obtained in many old ham magazines written before 1965 or so. I found my Q5er with power supply at a ham fest for $5. (Skip Arey)

A.D.P..RES.S.P.S: Fair Radio Sales, 1016 E. Eureka, Box 1105, Lima, OH 45802 has con sistently been one of the best suppliers of /URR equipment and supplies for many years. Their catalog is free, and if you purchase from them regularly, they send you catalog supplements and a new catalog each year. Davilyn Corp., 13406 Saticoy St., North Hollywood, CA 91605 has a flashy catalog for $2. Their prices are somewhat higher than Fair’s, but they have some items which are not available elsewhere. For plugs and connectors, try Kings Electronic Co., Inc., Marbledale Rd., Tuckahoe, NY 10707, Colonel Wayne Russell, 9410 Walhampton Dr., Louisville, KY 40222, or The RF Connection, 11707 Judy Place, Potomac, MD 20854. Colonel Russell also has a good supply of /URR manuals. For tubes, my favorite is Daily Electronics (who bought out D. R. P, Electronics), P. O. Box 5029, Compton, CA 90224. Send them an SASE with a list of the tubes you want, and they will quote you a price for each. Include $2.50 for shipping and handling with each order. They do not have a catalog. Two other highly recommended tube suppliers are RF Gain, Lt., 100 Merrick Rd., Rockville Centre, NY 11570 and Don Skinner, WA8BIE, RFD 1,

New Carlisle, OH 45344. For the rare 3TF7 you might also try Gerber Electronics, 128 Carnegie Row, Norwood, MA 02062. (courtesy of your Ed. and HSN subscribers)

THE R-390A 0N LONG WAVE — CHEAPLY

Craig Healy

The R—390A is a fine receiver, and many of us are quite familiar with it. A major drawback is that it doesn’t tune below 500 khz. Or does it? A look at the schematic shows that the local oscillator in the 500—1000 khz range does indeed track from 500 down to O khz. Working backwards from the first mixer we find the first and only bottleneck. The antenna coils and RF amplifier tuned circuits are the culprits. They stop at 500 khz and 1 go no lower.

As an experiment, I removed the top covers from my R—390A and coupled a longwire antenna through a 0.05 mf capacitor to “test point E-209.” This is easily accessible from o the top, and is found just in front of V202, the first mixer. Voila! Most of my strong local LW ststions were heard, along with an assortment of BCB spurs, nvf products, and other electronic garbage. The spurious responses were to be expected because there was no tuned circuit between the antenna and first mixer. Next came some preselection in the form of a ferrite loop antenna. The loop output was connected to E-209 with a piece of small coax and the 0.05 mf capacitor. This gave greatly improved results. There were very few BCB spurs, and an improvement in sensitivity. Apparently the loop compensated for much of the lost R—390A RF amplifier.

A variation of the first experiment gave better results, practically equaling the performance of a Drake R—7A used for comparison. An old coil from a 1939 vintage RCA BCB o transmitter [model number? Ed.] was found in the junk box. This is a large coil, with 70 turns of #16 solid wire around a 6.5 inch ceramic and phenolic coil form. A smaller coil of 19 turns was mounted inside it. This small coil was rotatable to vary the coupling. Older members of our fraternity will recognize this as a variometer, con-mon in the early days of radio, but seldom seen nowadays. In this particular unit, the coil had taps on every other turn. A 10—440 pf variable capacitor, also from the RCA transmitter, was used to resonate the circuit. The long wire antenna coax was connected to the smaller, rotatable coil, and the variable capacitor was connected to a tap about 75% up the main coil from

ground. A tap point two turns from the ground end was selected as the feed point for E-209. Optimum coupling between the small inner coil and the large outer coil varied from maximum at 200 khz and below to a very small coupling value at 400 khz. This may be more a function of the antenna I used than anything else.

Unfortunately, the 1939 RCA transmitter parts are dificult, if not impossible tb find. [Fair Radio sells an RCA ET-8003 LF telegraph transmitter for $79 which may be suitable. Ed.) Perhaps an equivalent circuit could be constructed with a ferrite toroid. A suggested schematic is given to the left. The toroid should have two windings — a main coil with taps to adjust the frequency range and feed E-209, and a second winding with taps for varying the antenna coupling. As a starting point, use turns ratios like those mentioned above. The shield of the long wire coax can be left ungrounded, only connected to the coil ground. I have experienced some noise reduction when connecting the coil and long wire coax in this manner. However, the far end of the coax should be grounded. [? Ed.] I have used an antenna tuner identical to this on the BCB with good results.

[I have not used Craig’s approach to long wave reception, at least not as he intended. But after reading his most illuminating article, it occurred to me that his method could be used to convert the R—390A into a high dynamic range, precision, low frequency spectrum analyzer. For example, I had always wanted to measure the 6 and 60 db band widths and stop band of mechanical filters. A signal generator, a simple input and output impedance matching circuit using two BCB ferrite “loopstick” antennas, one stage of FET amplification between the mechanical filter and the output, and my dream came true. The output of my test circuit was fed into E-209, and the R—390A provided the relative db measurements via the carrier meter, with frequency measurements accurate to within 300 hz. A complete description of my experiments will appear in a future issue of HSN. Ed.]

PUBLISHER’S CORNER

It is Dallas’ and my hope that all those who weren’t in on the first four issues of HSN (a.k.a. The R-890 User” Group) will enjoy this compendium. We are continuing 1 in the tradition we began almost four years ago — to publish the best information about hollow state mods, tubes, parts, and tools sources, and the very best in readers’ comments, projects, and reminiscences about hollow state equipment. 1

A few months ago while perusing a leading communications magazine, I came across the term “hollow state” used to refer to tube type equipment. I knew then that the term, which was coined by Skip Arey, had arrived in the language when it was used with no quotes around it. If nothing else, we’ve added a term to the language, but more than that, we hope we have added to your knowledge and enjoyment of hollow state equipment. We also hope you will write Dallas about your construction projects, tube sources, and experiences with hollow state gear. The other 132 readers of HSN will be eager to read your comments.

And now the usual All articles and information shared through this newsletter may be reprinted only with permission of the author. The publishing committee assumes no responsibility for the accuracy or safety of untested modifications or the reliability of suppliers of materials and services mentioned in HSN publications. Prices quoted on the masthead apply to the USA, Canada, and Mexico (double all quoted prices for all other areas . Checks must be made payable to Chris Hansen and must be in USA funds payable in U A clearing house format. Write for an information sheet; include a SASE.

Thanks for your su port. We couldn’t and wouldn’t d it without you.

FR390 USERS GROUP

o A NEWSLETTER FOR URR USERS

SPRING 1983 FIRST .1SSUE PUBLISHER T.J.

A RUMOR IN ITS OWN TIME!

ELCOME to our experiment! I want to take a brief line to thank you all for ‘our support, You have made this first issue possible. Lets get started.

From DALLAS LANKFORD comes this commerlt on TUBES: It is said that 26ZW5 ecti fier tubes are no longer made, and I have never seen a source for them or he RT510 (3TF7 in early R-390A’s) current regulator tubes, Modifying the power supply to solid state solves the rectifier tube problem, while the RT510 may b emoved and a ²+2 ohm 5 watt resistor “plugged into” pins 2 and 7 of the tube ocket, The 6AK6 line AF output and local AP output tubes seem scarce, with TCO Electronics, North Country Shopping Center, Rt. 9 North Plattsburgh, N.Y.

12901 the only source I have found, The remaining R-390 tubes are easier to ind, but Radio Shack and other retail prices are high. Two other reasonably riced tube source are EDLIE Electronics, 2700 Hempstead Tumpike, Levittown,

Long Island, N.Y. 11756 and Translectronic, Inc. 1365 39th St. , Brooklyn, N.Y.

11218 (in the latter case ask for both regular and industrial tube lists) •

(Translectronic has a toll free number 800-221-5802 and a minimum order of

$25.00 so get together with someone on your tube purchases through the R-390

Users Group Newsletter. SKIP) NEAL PERDUE warns that one should be cautious choosing a modi Cication to replace the 3TP7 tube, It appears that some hods are better then others. Watch these pages for a source for this tube in a future issue, Also keep an eye out for tube modifications dovm the road.

SALES DEPARTMENT Some people actually sells these rigs ya know, is up for by KEN Schroeder ct. ,

OH, 43613 phone 419- ¹475-3089 He’s asking $350 or trade for solid receiver 1

R-388 can be had from TONY BRATTON 423 Summit St, Marquette, MI 49855

R390A (serial #37) with manuals and CV591A SSB converter. is available from oWBOMIX, Rt 2 Box 357, Willow Springs, MO 65793 phone ¹1.17-469-3370 for $450 plus you provide the shipping, ( from March 1983 QST)

SPEAKING OF SHIPPING: Anyone with creative ideas on how to move one of our o beloved URR5 with no darnage to cither rig or ovmer might write up their ideas for this newsletter,

CRIS HANSEN ‘S Bronx NY apartment was once stripped by burglars. who took everything but his R-390A. What burglar in hi G right mind would try???

PUBLISHING DATE ON ISSUE TWO IS THE SECOND WEEK IN JUNE. SEND IN YOUR ARTICALS This is a USERS GROUP and your contribütions will keep this newsletter helpful informative, thought provoking and most of all regularly published,

AS IF YOU DIDN”T KNOW: A excellent source for almost anything for the R-390 d its kin is FAIR RADIO SALES, 1016 E. EUREKA, BOX 1105, LIMA, OHIO 45802 ne: 419-227-6573. They ape currently listing the R-388 for $265 used and

330 checked, There is no truth to the namor that I bow toward Lima five times a day, They are also a source for the hard to find connectors used on URR equipment, I spoke with them recently about our users group and they said they would keep me posted on any new stock of receivers and related i terns ,

MODIFICATIONS: JIM HERKIMER writes that he uses a modification suggested by

ED SHAW for increased audio gain, Jim has placed a jumper across pins 6 and 8 on the teminal strip on the back of the R-390A. (It works great. SKIP) Jim also says he experiences slightly higher gain using the unbalanced antenna input as opposed to the balanced input,

DALLAS LANKFORD found that drift can be reduced in the R-390A by changing th temperature compensating capacitors (10pf N^I*50 and 10pf NIOOO)to NPO zero temperature coefficient units rated at 20pf. Thats capacitors C702 and C703 by the way.

Ever have a tuning core fall off its rod? WAYNE HEINEN solved this problem as follows. He removed the adjustment screw from the bracket by taking out the two phi 1 lips head screws, removed the bracket, and unscrewed the adjusting screw all the way out. He took a small amount of epoxy and put it on the end o the adjustment screw and jammed it into the hole in the ferrite rod. He then waited 15 minutes and then found that the adjustment screw with the rod firmly attached came right out. Wayne then carefully re-screwed the adjustment screw with the ferrite rod attached back into the mounting bracket and aligned the adjustment screw bracket with the tuning bracket, inserted the phi 1 lips head screws and proceeded with the normal -peaking proceedure,

CHRIS FANSEN suggests that you remove all of the tube shields for improved cooling performance. Has anyone who has performed this modification run into any problems? I arn thinking especially of any harn who might be operating in conjunction with a high powered transmitter. I have had no problems here running three hundred watts

The H. CORNELIUS pathway to improved SSB performance on the R390A. The major reason for poor SSB performance of the R390A is inadequate automatic gain control (AGC) which fails to keep SSB signal strength at the diode detector below the level of the BFO, thus causing severe distortion on strong signals. The changes listed below increase AGC action and greatly shorten the attack time, The end result is greatly reduced distortion on SSB and a somewhat be RATT performance. This modofication should take 0-40 minutes.

1, Remove TP subchassis. 2, Install a diode (IN3R/1N60/1N914/1N4148) in place of R546 (180K) , with diode cathode facing the tube socket, 3, Remove R5¹45 (100 resistor. 4. Replace R547 (220K) with a 10K resistor. 5. Examine R504. If it is not 560 ohms, change it to that value. (This was a production change in some models) • 6. Replace the IF subchassis; realign the BANDWIDTH and PITCH knobs, If you happen to have a few 6AU6 tubes around the shack you. might do the following while your in there. 7, Connect a DC voltmeter to read AGC volta (negative lead to terminals 3/4 of TB102 on rear panel, positive lead to grounc 8 . Tune a steady signal, such as a calibrate marker. 9, Try various 6AU6 tubes a.s V508 and select the one giving the highest meter reading. 10. Connect a DC voltmeter to read detector voltage (negative lead to terminals 14/15 of TB103 on rear panel, positive lead to ground) 11 Try various 6AU6 tubes as V 505 and select the one giving the highest meter reading. 12, As a final adjustment, th1 GAIN ADJ• control on the IF subchassis should be set for the least usable gain. Too high a setting increases distortion and produces high AGC voltage, which, applied to the front end of the receiver, decreases the signal-to-noise ratio.

DO YOU KNOW OF A MODIFICATION OR PRODUCTION CHANGE ON URR EQUIPMENT? SHARE IT

THROUGH THE PAGES OF THIS NEWSLETTER. EVEN IF IT IS COWON mOWLEDGE TO YOU IT MIGHT BE A NEW IDEA FOR SOMEONE ELSE, WRITING FDR THE R390 USERS GROUP IS THE EASIEST WAY IN THE WORLD TO ADD THE TITLE OF TECHNICAL WRITER TO YOUR RESUME.

Your most dedicated and humble publisher has a NEW PHONE NUMBER 609-877-5302 Please use this number for all calls because my old number belongs to my mother-in law. She will throw us out if she gets late night calls and then might have to move my R390A and you know how hard that is.

What has seventeen dials, two meters and is loads of fun to carry around? Answer: If you don’t know you are subscribing to the wrong newsletter!

ITS REALLY A PORTABLE, IT EVEN HAS HANDLES. this one via JOHN COHEN,

ANUALS: Many of our newsletter mavens have volunteered to provide photocopies f the various manuals for our equipment. From time to time I will include these names in the newsletter, But our inaugural issue deserves nothing less hen PHIL BYTHEWAY’S list of military manual services, PHIL finds that the best ource for manuals is that depository of tax dollars, the US MILITARY, It seems e services will reproduce our much needed manuals at the rate of per page us two dollars shipping and handling, Manuals for ARMY issue gear can be purchased from the U.S. ARMY ADJUTANT GAERAL PUBLICATIONS CENTER, 1655 WOODSOr ROAD, ST, LOUIS, MO 63114. Manuals and prices are as follows.

R-389 TM 11-855 ($1 .45) T echni cal Manual 11-5820-36-24? ( .57) *

78) Changes 3′ 5+6

R-390A TM11-5820-358-35. ($1.89) Maintenance Manual -10 ( .39) Operators Manual -20 • ( ?

-20P. ( .36)

-31+Pt ( .96) * R-392 TM 11-5820-334-ESC( ?

—10 ( ? Operators Manual

-20 ( .39) Intallation & 2nd eschelon maintenance

-20P ( .40) ** 34 p ( .88)

Direct support; and general support maintenance repair parts and special too lists.

** Organizational maintenance repair parts and special tools lists

Whats the matter bunky? Ya say yer radio was honorably discharged from the NAVY? the write to the NAVAL PUBLICATIONS & FORMS CENTER, 5801 TABOR AVE. PHILADELPHIA, PA 19120

R-390A 0967-LP-063-2010	Operation, Maint enance
-2011	Change 2/18/72
-2012	($3.51)

-2013

-2014

PHIL says that you may only purchase one copy of each of these manuals per

person.

JOHN KAPINOS has found out that the U.S. ARMY is not deactivating R-390A’s due to bugetary limitations •

DAVE SCHMIDT tells me that every now and again URR gear can be found amongst the junk “lots” auctioned off through the Defense Department Surplus Sale Cataloge. These lots are sold for scrap and go for very low bids but one lot he knew of contained 2 R390As(be still my beating heart) I will get in touc with DAVE to find out more for a future issue,

Contrary to popular belief you do not tell the Amy equipment form the Navy equi ment by their tatoos.

WANTED: PHIL BYTHEWAY 9705 Mary NW, Seattle Wash. 98117 is looking for a VFO for an R-389.

YOUR PUBLISHER, 104 West Franklin Ave. Edgewater Park, N.J. 08010 is looking for any information on the SB-8a Type T-200 Panalyzor. US Amy Signal Corps issue Panadaptor. It looks great in the rack over the R-390A but I’m lost as to how to resore it. CAUTION* ** Anyone planning to purchase one of these

1 panadaptors be advised that the power supply is a seperate outboard unita Don get one without the other.

VERYONE is looking for sources for tubes parts and racks. Please share •your sources through our newsletter.

We will be looking for a group rate on trusses for subscribers who live in second floor apartments

Look at it this way, If I use up all the jokes in issue one you wont have to read them in future issues. Unless, of course, you provide some n

I •age four

A’RTICALS WANTED: There are a few ideas for articals that come to mind through the correspondence leading up to this premiere issue e Por instance. FREQUENCY ‘COUNTERS: While the mechani cal readouts are without compare, has anyone out in newsletter land investigated the possibility of interfacing a frequency counter with URR equipment. ANTENNAS: hat works for you and your receiver. PRESELECTORS AND PREAMPS: Many people out there are using them, tell us what kind and how you think it stacks up in signal improvement. SPEAKERS and other audio support gear such as active filters etc. NOTCH FILTERS: has anyone thought of adding an RP notch filter to the R-390? Write up your ideas on these and a.nything else about modification and improvment and share bit in the newsletter. This project could end in its first year if we don’t all do our »part to fill these pages with infomation. Keep those cards, letters and schematics coming folks,

This might be a good place to give a plug to those gave our effort its initial advertizingu NATIONAL RADIO CLUB, NORTH AMERICAN SHORT WAVE ASSOCIATION SPEEDX, GLEN HAUSER’S WORLD OF RADIO PROGRAM AND ALL OF YOU Mio TOOK THE TIME

TO SHARE THE INITIAL MAILING WITH OTHER DEDICATED LOVERS OF FINE RADIOS,

And while we are at- it a list of charter members whose subscriptions served to offset the start up costs of this project. WAYNE BAIKINNEY, KEN ROMSTADT, JIM HERKIMER,’ .DALLAS LANKFORD, DICK TRUAX, NEAL PERDUE, MATT STUTTERHEIM, JOHN

KAPINOS, CHUCK HUTTON, GEORGE MULFINGER, CHRIS HANSEN, RON MUSCO, BILL BAILEY, BOB BOWES, BOB MILNE, CHARLES TAYLOR, ROBERT KULOW, TOM FARMERIE, JIM PHILLIPS, ED KOWALSKI, PHIL BYTHEWAY, BILL HOPKINS, BOB LOMBARDI, AND JERRY BERG, and your humble publisher make twenty-five dedicated (read that rabid) hobbyists.

I contacted ANARC (the Association of North American Radio Clubs) about affiliating our newsletter with their group, TERRY COLGAN said that a users group has never been considered. Perhaps if we called ourselves a club there would be less of’ a problema He did not rule out the possibility however, The main requirement for affiliation is that the club be active for six months. I will •be attending the ANARC convention as the representative of the NRC but I intend to bring the possi bility of affiliating our users group at that time. If your not doing anything July 15-1? You could join me in my efforts at the convention n Also you might petition your various clubs that you belong to to gain their support in this effort. But before I climb to high on this please write and share your feelings about this with me and your fellow newsletter folks.

Many of you have sent in articals about the R-390A and R-388 That I would 1 liek to use, The biggest problem lies in obtaining permission especially from people who have written for the commercial magazines such as HAM RADIO and CQ, Please try to write for permission to reprint these articals before they are sent to the publishing shack, This might get them into these pages much faster,

SO MUCH F’6R BUSINESS: ON TO ANOTHER MODIFICATION! ! 2 This might be a moldie oldie fo•r some of the more experienced owners but for the rest I give you DALLAS LANKFORD and his POWER SUPPLY MODIFICATION. If this mod has been done incorrectly in your R-390A, it deserves immediate attention. My most recent manual (1970) describes the solid state conversion without the dropping resistor R (see accompaning diagram) , However the diodes increase the B+ voltage from about 2²+0 VDC (with the 26ZW5 tube rectifiers) to about 270 V^DC with the diodes) . If a dropping resistor is not used to bring the B+ dowl to 240 VDC, the 6AK6 line AF output and local AF output tubes will operate beyond their maximum ratings, with excessive tube failures and possible damage to associated componants, So any R-390A user should check out the power supply. the converted solid state power supply schematic is showi on page five. Any 1000 PIV I amp or better diodes are adequate (IN 561, Radio Shack 278-1627, Sylvania ECG 125, etc. ) . For the dropping resistor I use a 25 watt power rating f’or better reliability and heat dissipation, Perfectionists can diddle with the value of R, but I settled on 200 ohms.

(Cont . on Dap,e 5)

wer supply mod cont: There are several potential ways to do the mod, from as mple as soldering the diodes across pins 1 (or 6) and (or 8) of the 26ZW5 sockets and remove the tubes, to as complicated as removang the tubes, sockets d their associated circuitry before adding the diodes. If the dropping sis tor is to be mounted on the power supply subchassis, the latter approach e should probably be used to facilitate mounting the resistor for good ilation (the dropping resistor gets quite warm) In my opinion the prerable place to mount the dropping resistor is on the AP subchassis. B+

Itage enters the AF subchassis through pin 5 of J619 and is then routed to

L601 by an insulated wire (which is part of a wiring hamess) The AF chassis s a plate which covers holes in the chassis, and so is a convenient place to unt a-dropping resistor. One hole is drilled for mounting R on top of the

AF chassis, and one hole is drilled to bring two wires from the underside of e chassis„ Cut the wire which provides B+ to L601 at pin 5 of J619, pull the re out of the wiring hamess until there is enough slack to reach one of the solder lugs on R, and solder to that lug, Remove any solder and wire or other sidue from pin 5 of J619, and then solder a length of insulated wire to pin which is long enough to reach the other lug of R. be sure to save and re-use e insulating sleeve which origionally insulated the pin 5 solder joint and luge If I remember correctly, wire size is #22 stranded. Because many R-390A ers will probably convert their power supplies to solid state, it would be good id€a to settle. upon a standard approach. Mounting R on the AF subchassis is apparently commonly used by hams, so I have used that approach

LLAS also has a few words to say about TOOLS: A neophyte who doesn’t recogi ze that all of the set screws and socket head screws throughout an R-390A are multiple spline (also known as fluted Bristol) will probably strip one or wo of these impossi.ble to obtain items. The military manuals call for a luted no. 8 Bristo (sic,) wrench, which is not how the wrench is described in current catalogs. The military also seems to have misspelled Bristol throughut their manuals 0 The equivalent wrench in current terminology is a 0096″ tol 6-flute wrench (also called a screwdriver) , Xcelite makes a good ertable tip (model 99-66) for use with various handles ( the Xcelite model

9-1 regular handle is suitable) . I would also recommend the ^IV’ extension

Xcelite model 99-X5) . My R—390A also includes a few sockets which require a

111 tip (model 99-67) . If you work much with military surplus equipment it would probably be worthwhile to get a complete set of spline wrenches. General ement also makes a set of small, L-shaped, spline key wrenches, GC

5070 which includes the #8 sizen (please send us the company address. Dallas ,

SKIP) You will also need good quality Phillips head screwdrivers in various ead sizes, and I have found the Sears Craftsman #9 ²0441 10-piece combination gni t ion wrench set very useful for the many small nuts in the R-390A.

ere is (mother good question: hat kind of lubricant do you use on the ear train of your receiver???

Well th ere you have it. Our first issue. You made it possible and ou Wilf continue to keep this thing mar-ming with your supporta If you can h ink o f’ nnyone else who might be interested in our group please let them know about it.

HE R390 USERS GROUP

8010 (609) 877-5302 Publisher: T .J. Skip Arey WB2GHA

All articals and info mation shared through this users group may be repri nted with the permission of the author only.

newsl etter is available at the cost of $1 .00 per issue. Back isSues availabl e of all issues through the publisher at the same cost of $1 .00

1per issue. An i.ndex will be published of back issues in the first issue of future volumes t,

HE NEXT PUBLISHING DATE IS THE WEEK OF JUNE 12TH, GET YOUR ARTICALS IN EARLY.

ÆR390 USERS GROUP

A NEWSLETTER FOR URR USERS

2 a tradition since March uuu

TYPIST cutis unsn

: •HELLO AGAIN frm the hub of the R390 publishing world. We are now seventy manbers strong, Once again thank you for the supoort and your contfnued supply of Infomatfon for this exchange. Welcme our typist and staff gramarfan Chrls Hansen. The newsletter be sent out frm his local but please continue to direct all Infomatlon, questions, threats, etc. to the publisher, In other words, don’t shoot hfm, he’s only the typist,

: You will notice that we are now pub”shing 6 pages double-sided, Thls is In order to reduce shipping weight. Five pages single-side cmes too darn close to turning the

Into a postage-due sftuatfon. Please keep sending Ideas and infomatlon so that we might fill a full six pages fn every issue. Next publlshlng session will be September 12, 1983. Support the group.

If H, CORNELIUS’S SSB modification In issue 1 was not your cup of tea you mfght take the advice of ROBERT ROTELLA and contact G.B. cwtJNICATIONS, 963 Birch Bay Lynden Road, ‘Linden, WA 98264. They have developed an adapter that provides undlstorted receptlon of SSB, CW, and RTTY — sort of a teeny CV-157/URR. This unit mounts with no

modlflcatlons to your rig, is completely solid state, and does not affect other modes of camunlcatfone It sells for $25.00 plus 6% sales tax for WA residents. ROB Is • very py with his.

I received a call from KEN Rff4SDAT stating that his recently acquired R390 does not operate In the lowest MHz posltfon. Operation appears nomal In all other bands.

you have any advice you might contact KEN at 2541 Schroeder Av., Toledo, OH 43613,

(Typist’s note: Check to see whether any of the tuning slugs have fallen off

•the slug rack Into their transfomers, ch)

PSSST! HEY BUDDY! Looking for a good deal on a htly used radio? DAVILYN CORPORATION

13406 Saticoy st., North Hollywood, CA 91605, tel. 213)787-3334/3338 has recently

1 purchased a large quantity of R390 and R392 receivers, These rigs are guaranteed in working order and sell for $285 for the R390 and $250 for the R392. Go get ’em folks. Incidentally, DAVILYN is also a source for almost any surplus gear and assorted parts, Includin tubes. They do not, however, 1 {st the 3TF7 in their most recent catalog . Look out, FAIR RADIO SALES. DAVILYN told me that they will soon begin advertising these rigs in popular han radio magazines, so if you or a frfend are In the market for an R390 or R392 you might want to act wlth sme haste.

Looking for a source for coax fittings for all those plugs on the back of your URR radio?? Try KING’S ELECTRONICS CO., INC., Marbledale Road, Tuckahoe, NY 10707. I found all my connectors at hart radio flea markets, If you’re not a ham, you might check QST or CQ Magazlne to see when these activities are scheduled In yo.ur area, Flea are great sources for almost• anything for your rig.

JERRY BERG tells of another source for tubes, including the’ much-sought-after 3TF7.

00)232-8100; New England, NY, Nå (800)2Æ-1800). Tie price (are you sitting down?)

$15.19 wlth a $5 handling charge on orders under $25. Your humble publisher, In concert with one of our subscribers Is tracing down another source for this and many of the much-needed tubes for our beloved R390’s, 392 ^Is, 390A ^ts, et al . Watch these pages.

WANTED. . . The publishing staff (me) is looking for someone to manage the task of coordinating the sharing, copying, and exchanging of manuals for our users group, Of the 70 of you, more than half have either manuals to share or requests for specific manuals. This pl aces the task outside of the scope of your humble publisher. However, I krm that a few of you out there are not dust military radio collectors; some of you are also military manual collectors. Perhaps one of you would step forward and become the clearing house for manual exchange in our group. You say you need a proper title? How does LORD HIGH MAYOR OF MANUALS grab you? No good? Well, volunteer anyway and think of sanething better. See how our group is growing and evolving right before your eyes!

Speaklng of MANUALS…BILL NEIL says that to obtain manuals through the sources listed In Issue one requires first getting approval of the proponent agency (e.g., Naval Electronic

Systans Camand, Technical Publications Branch. He also states that in the last month or so release policies for manuals have tightened up considerably. So it looks like for

the time being we must depend on each other as sources of infomation. Well, that’s

the R390 modular subchassfs can be easily ranoved frm the receiver mainfrane, thus distributing the recei ver ^ts 85 pounds mong the two UPS parcels. Removal of the approprl ate subchassis modules requfres only 15 minutes worth of effort. First, the heavy poær supply subchassis should be ranoved fran the receiver mainframe, followed by the audio subchassls (both of which are mounted on the underside of the mainframe), and then, finally, disconnect all Interconnecting cable assemblies to these three subchassis. Then, •with a Phillips-type (or Bristol-type, see issue screw driver, loosen the green-headed captive screws on each Individual subchassis. You do not have to worry about losing these green screws, since they are captive and will not fall out. On the audio subchassfs you will have to loosen the two shaft-extenders on the selectivity switch and BFO knobs to renove the unlt frm the mainframe. Leave the RF deck and the VFD as they are mounted in the mainfrane. With the power supply, IF deck, and audio deck removed, welgh the renainder; it should now be less than 50 pounds likewise for the three subchassls modules which, when packaged, will be the second UPS parcel .

In response to our request for shipping strategies comes this method from JIM HERKIMER: United Parcel places a weight limit of 50 pounds on any single parcel and a restriction of only two 50-pound parcels destined for the same recipient on a single day. A few of 1

In the Interests of editorial fairness and all that, we will probably, from time to time, publish modifications to replace the 3TF7. But we will also publicize tube sources. My opinion? Resistors are cheaper than tubes, so if Uncle San could have gotten away with less than the tube, he would have. (cane now – the Pentagon loves cost overruns.ch)

Frm STEVE BNC cmes the reason why one should NOT remove and modify the 3TF7 tube even If the darn things are starting to cost as much as the receiver itself. Steve does not recomend replacing the ballast tube with a resistor, The ballast tube is an autmatfc rheostat which keeps the current constant to the receiver circuitry despite the current/voltage surge when the equipment is first turned on. (This sounds suspiciously like a soft-start resistor. sa) The resistance of the ballast increases as the supply voltage Increases, or if there Is a sudden surge. Unfortunately, a simple resistor will not perform this function.

Question for a future article: Has anyone been fortunate enough to own two working 1

R390’s or other URR rigs at the sane time and tried wiring them together for DIVERSITY RECEPTION? I have had good luck with this reception strategy with other rigs but, alas, I own onl.y one R390A.

FOR SALE DEPARTMENT…DICK TRUAX, 3003 Gleeson Lane, Louisville, KY 40299 has a Collins R390 (not “A”) in excellent condition with cmolete manual for $325.

YOUR Ht.NBLE EDITOR has a metal cabinet just right for the R390 or R390A for sale, Contact via publishing address: 104 West Franklin Av., Edgewater Park, NJ 08010. Have smething to sell or trade”? This is the place…..

rm CRAIG-HEALY comes this article he oriqinally wrote for “LOWDOWN”

THE R390A ON LONGWAVE CHEAPLY

R390A Is a f Ine radio, ind most of us are quite f aniliar with lt. A major drawback s that it doesn’t tune down below 500 kHz. Or does it? A look at the schmatic tms that the local oscillator In the 500-1000 kHz range does indeed track all the way to O. kHz. Working backwards frm the first mixer we find the first, and only bottleneck. The antenna cons and RF anplifler tuned circuits are the culprits. They top at SOO kHz and go ;.no lower.

As an experiment I ranoved the top covers from my rig and coupled a longwire antenna

1through a .05 mf capacitor to ‘test point E-209’ . This is easily accessible from the top and Is found right In front of V202 (6Cd), the first mixer. voila! Most of my strong local LW stations came in, along with an assortment of BCB spurs, 1M products, and other electronic garbage. This cmes frm indecting a broad spectrum of signals to the grid of this tube.

Next cane sme preselection in the fom of a ferrite loop antenna. The loop amplifier output was connected to E-209 with a piece of small coax cable and the .05 mf capacitor. This gave greatly Improved results. Very few BCB spur troubles, and an improvement In sensitivity. The loop amp offset the loss of the R390A RF amp.

The next experiment gave the best results of all , practically equalllng the perfomance of a Drake R7A used for cmparison. An old coll frm a 1039-vintage RCA BCB transmltter was recovered frm the junkbox. This Is a large Diece, with 70 turns of sol Id wire around a 6-1/2-lnch ceramic and phenol ic fom. A smaller coil of 19 turns of the sane type of wlre Is mounted inside lt. This small coll is rotatable to varv the coupllng between the two cons. The older manbers of our fraternity WI 11 recognize this as a iocoupler, camon fn earlier years, but seldom seen today. This particular unit taps on every other turn on the main outer con. It resonated nicely with a 10-440 pf

c.acitor, also fran the RCA transmitter. The LW coax feed was hooked to the smal ler, rotatable coil. One end of the maln con was grounded, along with the frme of the vari able capacitor, The stator of the cap was connected to a tap about 3/4 up the main coil frm ground, A tap point 2 turns up frm ground was selected as the feed point for the radio, Optimum coupling between the small, Inner coil and the outer con varied frm maximum at 200 kHz and below to a very small value at 400 kHz. This is probably more a function of the antenna I use than anything else.

These parts are difficult, if not impossible to get. I have no doubt that equal or better results could be had with ferrite toroids. •An equivalent scheme would have a large toroid core with three windings. The first Is the main tank circuit. Taps can be provided to Increase the range of frequencies it will tune. The second is a link feed to the radio, The best number of turns can be experimentally determined and should renain the sane over a wide range. The third is the antenna Input, tapped for varying the Impedance the antenna coax sees. The shield of the coax feed can be left ungrounded, only connected to the con. I have found some noise reduction in connecting the coll across the coax in this fashion. The far end of the coax must be grounded, however. I have used an antenna tuner: Identical to this on the BCB with good results.

Well, what do you think of that, Canpers??? Another band for your radio that you didn’t even know was there. We are also looking for articles on various antenna strategies.

Just what do you think Is the best antenna for the greatest receivers ever made??? Write and Join the contributing staff today!

STEW MAC KENZIE Is looking for a source for an audio module to repl ace the 27A7GT tube. Anyone who knows where these can be found might share it with the group.

Whatsmatter, Bunky? Ya say ya can’t get good audio response frm an 8-ohm speaker because the government fn Its Infinite wisdm chose another impedance? Well, take heart, dear friend, for all your problems can be solved by obtaining a 115-volt to 12-volt power supply transfomer, 4vanab1e at any Radio Shack, part +273-1385, current price $3.29. Just connect the pffmary (black) wires to your receiver and the secondary (red) wires to your 8-ohm speaker, and listen your 1 Ittle heart away.

TRUAX says that a good source for hard-to-find connectors Is COLONEL WAYNE RUSSELL, 9410 Walhanpton Drive. , Louisville, KY 40222. His 1 ist of available parts can be obtained by sending him one dollar.

PLEASE KEEP IN MIND that we also represent the users of the R392 and similar gear. If you know of any modifications or Improvanents that will work on this equipment please help to see that it gets ftto the pages of our newsletter.

Frm DICK WALSER of AIRBORNE ELECTRONYCS CO. the that when making the power supply modification (issue you might want to use 2000-volt 62 amp diodes Instead of 1000-volt Jobs. Dick has had a lot of experience with thls modification and he says that the 1000-volt diodes smetfmes go “pop.” Incidentally, he has a good supply 26Z5 tubes, and you can contact him concerning these and other parts by writing him at 5028 Cartwright Av., North Hollywood, CA 91601. Phone (213)766-2747.

Here’s another questlon for you: Does anybody out there in newsletter land know what these URR receivers we hold so dear oriqinally cost Uncle San??? Also, I have received a fed requests for any history that anyone might be able to obtain on our equipment. Send your h.lstorfes In for the next issue.

No issue ‘of the R390 Users Group newsletter would be complete without some pertinent infomation from DALLAS LANKFORD, this time on meters. DALLAS gives us a source for meters the STRUX CORPORATION, 100 E. Montauk Highway, Lindenhurst, NY 11757. He suggests that when you write them you try to provlde them with as much Infomatfon as possible, such as manual series and part number frm that manual series. the going rate for both line and carrier level meters Is $20 each. Dallas feels that meter problems are probably cormon because under ⁿnomal” military use many URR receivers were operated 24 hours a day over a number of years. Upon repl acing a defective carrier level meter, the . repl acanent meter gave higher readings than nomal, with strong signals pinning the pointer. Dallas tried both 10- and 15-ohm dropping resistors, finally settling on the

5-ohm. One of the small, pronged, threaded, stand-off lugs was removed from the old meter and attached to one of the new meter screws to. mount the dropping resistor eatly. Dallas raninds us that. the only reasonable way to replace the carrier level ter Is to “drop ^Rthe front panel . In addition to the manual steps for ranoving the panel, Dallas found it necessary to release the cable clanp between the phone Jack local gain control to allow enough slack in the cable assembly. There are at least different meter styles which Dallas refers to as small- and large-window because of he relatfve sizes of the glass meter “windows.” The small-window meters seem to have aller numbers and letters. There also sem to be at least two different case styles, ne that cannot be opened without a special tool, and a similar style that can be opened ith a small screwdriver. Does anyone know what special tool Is required, and where L to obtain one???

ALLAS also gives us a list of R390 tube shields that should NOT be ranoved: the voltage regul ator, the PTO tube, the BFO tube, RF amp tube, and the three mixer tubes. (I guess I’d better put those back on huh???

e had a number of responses to our lubrication question, and most universal was 3-1N-1 on. I have had good luck with LUBRIPLATE white gear grease. Also, if you obtain a eceiver that has caked and dried grease flaming the gear assemblles, you will have good luck ranoving this using either denatured alcohol or automotive carburator cleaner and Q-tips. You can get long-handled Q-tips from most tape recording supply stores, even Radio Shack.

This note concerning AUDIO GAIN modification 1 isted fn Issue $1. Increasinq audio gain by placing a dumper across pins 6 and 8 may cause Inaccurate line level meter readings.

MEMBERSHIP DIRECTORY TO BE PUBLISHED. Many of you have written asking for the names and addresses of your fel low newsletter folk. In the Interests of assuring- privacy we are

OUNCING THE PUBLICATION OF A MEMBERSHIP LIST. If you DO NOT want your name, address, e etc. listed on this 11st please wrlte pub”shing central so we can keep this Infomation out of the 11st. By and large, however, I think everyone seems to be more than eager to be in touch with one another, but, Just In case, please heed this notice.

THREE METHODS OF REPLACING THE 3TF7 IN THE R390 AND R390A RECE EVERS

(FOR R390) Replace V508 and V701 (PTO & BPO tubeg) with 12BA6’s. Short pins 2 and 7 on 3TF7 tube socket with a shore piece of wire. (POR R390A) Replace V505 and V701 (PTO & BFO tubes) with 12BA6’8 and short pins 2 and 7 on 3TF7 socket.

(SAME FOR BOTH RECEIVERS) Leave 6BA6’8 in PTO and BFO societs and put a 42 ohm resistor (5 watt) across pins 2 and 7 on the 3TF7,
(SAME FOR BOTH RECEIVERS) Below ig a Triac regulator circuit which can be plugged into pins 2 and 7 on the 3TF7 eocket. Ground to one of tube mounting screws,

ADJUST POT

12.” oc

AT PIN 7

The above Infomation on 3TF7 modifications comes from DICK TRUAX. Incidentally, some of you might be Interested fn the fact that the 3TF7 was later produced under the number 3HTF4, These and other tubes can be purchased from AMPERITE, 600 Palisades, Union, NJ 07087.

R%MBER THIS IS A USERS GROUP! !! PLEASE CONTRIBUTE ANY AND ALL INFORMATION SO THAT WE MIGHT SHARE IT THROUGH THE PAGES OF THIS YOUR NEWSLETTER!

Also, most of you, when subscribing, told me what kind of receiver you have. If you have not sent this Infomation in, •it would be helpful, so that I might try and drtm up more articles for your particular equiment. Or, for that matter, I might contact you to provide sme Infomation. Contrary to popular belief, I an not an electronics wlzard, and I have only owned by R390 for less than a year. So, many of you have more knowledge than I have to share.

Many of the people fn this group are BROADCAST BAND LISTENERS/DXERS (Try it, you’ll like It! ) NEAL PERDUE shares these tips concerning wiring your BCB AMPLIFIED LOOP antenna to your R390A. Much better nulls can be obtained when setting the AF gain control 1 to a cmfortable level (around 3 or 4) and using the RF gain as a voltme control, usually between 8 and 9. The setting will , of course, vary slightly depending on your local situation and band conditions. Using MGC gives boost.

This could be called the ‘pre-convention’ issue. I will be attending the ANARC convention in Washington, DC July 15-17, and the National Radio Club convention at Poquonock, CT Septenber 2-4. If you will be attending either or both drop a note to publishing central so we can plan to spend some time discussing the greatest radio receivers ever bunt.

THE R390 USERS GROUP, 104 west Franklih Avenue, Edgewater Park, NJ 08010

TELEPHONE (609) 877-5302, Publisher, Skip Arey; Typist: Chrls Hansen.

All articles and infomation• shared through this users group may be reprinted with the pemlssfon of the author only. The R390 Users Group newsletter is available at the cost of $1.00 per issue. Back issues are available through the publisher at the same cost of $1.00 per issue. An index will be published of back issues in the first issue of future volumes.

THE NEXT PUBLISHING DATE IS THE WEEK OF SEPTEMBER 11, 1.983. GET YOUR ARTICLES IN EARLY. YOUR CONTRIBUTIONS OF MATERIAL MAKE THIS NEWSLETTER POSSIBLE.

‘Il-DE SUPPLIER ISSUE ! ! ! ! !

/ R390 NENSLEITER /

P.O. BOX 421

HOLLY, NJ 08060

(Sorry, I left the nastheads

N 03 at hane! ! ! chris)

ELCOME AGAIN to our ever-evolving newsletter, As you can tell this is the Gala Tube uppl ier Issue. It is especially important to note in this issue (it of course should be oted concerning ANY supplier of parts and services) that we are publ ishing ALL sources for arts and services that cme into publishing central. We have neither the time nor inclination to thoroughly research these sources, as we assume that the users group enber who subnits the information has already done so, (We’re all in this together, ight?! ) so LET THE BUYER BEWARE! !! Consult sources as to prices and delivery times

BEFORE YOU ORDER! In addition, sme of the infomation might be dated. It goes wfthout aying (I guess that’s why I’m saying it) that if you find that any of the data are in rror or if you have a problem dealing with a particular source PLEASE infom publishing central imediately so that we can publish an update In the next issue.

ORK IS going painfully slowly on the membership directory, but I hope to have it all ogether by the hol iday season. If you have not already done so please send me a postcard with a listing of the receivers you are interested in or are using, Also, if you don’t ant to be included, please let me know that as well.

WE ARE STILL LOOKING FOR SOMEONE TO ORGANIZE THE MANUAL NEEDS AND WANTS. If you are terested in taking responsibility for getting members with manuals in touch with members out manuals, please contact me ASAP.

THE POST OFFICE BOX seans to be working out real well . A number of you have tried to contact me by phone and discovered the futility of that. I am not at hme nearly as much as I would like to be these days. The best way to get in touch is to drop me a postcard or letter to P.O. Box 421; Mount Holly, NJ 08060. I sorry that I do not get the opportunity to answer most letters due to time constraints, but all are read and all infomation Is filed to be shared through the pages of our newsletter. Also, all caments and criticisms are taken into full consideration. This is your newsletter and your feedback and infomation makes it possible. I just compile it and share it. Once again, thank you for all your support and ideas as we go through the growing pains of any new publ ication.

ANARC REPORT. 1 met long-time R-390 person MATT STUTTERHEIM at the convention, and in spite of all the new equipment like the SONY 2002 and the new BEARCAT receiver, I think our URR receivers are still the best. You must admit you will never lose your R-390A

under the papers on your desk, unlike sme of the new pocket-rockets that have hit the market .

WHO IS THE USERS GROUP MEMBER WHO ALWAYS PLAYS THE NUMBER 390 IN HIS STATE LOTTERY?

This issue brings to you perhaps the most Important information for your continued enjoyment of your receiver: TUBE SUPPLIERS.

Fran NEAL PERDUE comes this source for all R-390 tubes. D.R.P, Electronics, P.O. Box 4357, pton, CA 90224. This company requests a $15 minimtm order, Any duds or gassy tubes are laced free of charge, but Neal says he never received a bad tube in three years of dealing with the company. Prices are as follows, plus $2 for shipping and handling: OA2: $1.85; 6AK6: $1.75; 6BA6W: $2.10; 2625 rectifier for original power supply: $2.50; 5814A: $1.95; 6DC6: $1.85; 6AK5W: $2.50. The cmpany has no export Hcense so they will ship only to U.S. addresses. They ship via UPS and Neal reports that he usually gets his tubes 7 to 10 days after placing his order, If you have questions as to the availability of pny particular tube, l ist your particular needs down the left hand column Of your letter, preferably double-spaced, and they will return your letter with either a price quote next to each tube number or will note “no stock.” Neal did a great deal of research Into this particular company and he tells us that the company has a fairly good supply of 3TF7 ballast tubes.

DID YOU KNOW THAT THE 3TF7 AND THE RT-510 TUBE ARE INTERCHANGEABLE?????

And, just in case D:R.P cannot meet your needs, f rm Jim KowaÉki comes this bit of infomation. Jim is an engineer for Radio Station WJCM, and he learns of tube suppliers through his vocation. He recomends RF GAIN, LTD, 100 MERRICK ROAD, ROCKVILLE CENTRE, NY 11570, Phone 1-800-645-2322. Jim has made several purchases frm them and says that they have fast service and, while they require a minimtm order of $30, they do pay the postage. The cmpany does offer a free catalog, and they list all the tubes needed for the R-390, including the 26Z5W, 3TF7, 6082, 6AK5, and the 6C4. Jim also notes that they accept checks.

IT SEEMS THAT THE GOOD OLD DIODE TUBES ARE STILL AVAILABLE. If you operate out of a 1 damp basanent like I do, nice warm tubes are an asset, not a liability.

AND WHAT ABOUT TUBESTERS. These are solid state repl acanents for tubes. The primary source for these in hobby appl ications seems to be: SKYTEC, P.O. BOX 535, TALMAGE, CA 95481, Phone (707) 962-6882. Upon writing this company I was quoted a price for a full set of replacements for a Collins S-line ham station. I wrote again trying to explain our particular needs in more detail, but have received no response. Maybe one of our West Coast members might contact these folks so we can find out about the possibility of a “sol id state” URR station.

IF ANYONE ASKS WHY YOU USE AN R-390 TELL THEM YOU REALLY LIKE “HOLLOW STATE.”

HAMFEST HINT: Every now and then at a hamfest or even a regular fleamarket you might 01 find a box of old technical books. You might want to check through these obsolete tombs of wisdom for old military receiver manuals, but also take note of any tube data books. These are usually full of vital infomation on the care, feeding, and operating parameters of most tubes. The data will be especially useful if you are planning on modifying a circuit containing that tube. Also, most tube data books contain conversion and replacement tables that might suggest alternatives when your last 6AK5 goes PHFFFT. You will find that

these old books sell for pennies a pound, but will serve a useful purpose as you advance in years along with your vintage URR receiver.

A BRIEF MENTION OF TUBE SOURCES MENTIONED IN PREVIOUS ISSUES:

ETCO ELECTRONICS, NORTH COUNTRY SHOPPING CENTER, RT. 9, NORTH PLATTSBURGH, NY 12901

EDLIE ELECTRONICS, 2700 HEMPSTEAD TPKE, LEVITTOWN, NY 11756

TRANSELECTRONIC, INC., 1366 39TH STREET, BROOKLYN, NY 11218

FAIR RADIO. SALES, 1016 EAST EUREKA, BOX 1105, LIMA, OH 45802

DAVLYN CORPORATION, 13406 SATICOY STREET, NORTH HOLLYWOOD, CA 91605

GERBER ELECTRONICS, 128 CARNEGIE ROW, NORWOOD, MA 02062 AMPERITE, 600 PALISADES, UNION, NJ 07087

AIRBORNE ELECTRONICS CO, 5028 CARTWRIGHT AV. NORTH HOLLYWOOD, CA 91601

Now, then, with all these sources we should be able to keep ourselves in tubes for quite sme time.

But wait! Yet another tube source has been located, and it may very well be in your nei ghborhood . How’s that again??? Well , pay attention, Dear Reader!

A very good source for tubes can be any of the older, more established TV repair shops. A quick check of a couple of local TV repair shops revealed quite a few tubes useful to my various tube-type receivers and transmitters. In all three cases I was led to believe that the proprietors were glad to get these things off their shelves. I even

spoke to one gent who informed me that just a few weeks previous he threw out boxes of tubes (ARRRGH! Also, one day I was dutifully following my wife on her rounds of the local garage sales, ! ran across a fruit basket of tubes for 00, .half of

w) lich tubes tested OK, and most of these were imediately useful . So, it pays to scrounge , In contacting the TV repair sources, I find that personal contact works better an phone calls,

ou really want to be a purist about these things you might look around the surplus ets for any of the military issue ELECTRON TUBE TEST SETS. These are numbered

-7/U, TV-7A/U, TV-7B/U, and TV-7D/U, the manual for which Is designated

11-6625-274-35. I picked up by TV-7D/U for free frm a IOC41 ham, but I understand they can be had for around $5.

HAH!! Yet another tube source fran Dick Truax, who recomends: DON SK INNER, WA8BIE; FD 1; NEW CARLISLE, OH 45344.

is piece of infomation f rm Paul Gunn on connectors. Apparently, the UG-421/U onnector plug, the one for the balanced input, is available fran AMPHENOL under the part number KS 16288L2. Most major electronics supply houses and parts outlets for elevislon repair people can order Anphenol connectors for you.

Want to save the life of all your tubes, especially that coveted ballast tube? L.G. obertson says that the life of your tubes can be greatly extended by putting n A.C. themistor between the line cord and the wall socket. These devices are available fran most electronics stores under the names of “Workman Surge Stopper” for bout $5. When yo turn on the receiver this device gradually heats up and slowly and ently suppl ies th power to your precious receiver. These devices were very popul ar n the age of predominantly tube-type TVs, and I have heard that in sme cases they can double tube life.

o add another opinion to the ballast tube controversy, new member John Mohn says that the R-390 was designed to stay on a frequency plus or minus a few cycles for years and ears with line voltage variations from 95 to 135 volts and ambient temperatures from to 150 degrees. Unless you want to treat or use your set in the same manner, then s okay to make one of the modifications to replace the 3TF7. John also feels that leaving the tube shields on has a definfte value. “Why spend $150 for a mechanical filter o go in between tubes and then take the tube shields off so that half the signal ‘feeds around the filter in leakage frm tube to tube.” This Is true whether It is RF,IF, audio, or power tubes. Or, as John puts it, ⁿIf you want cool tubes, why not just cut the i lament leads and get it over with!”

SPEAKING OF COOL TUBES, I have seen a number of receiver owners using muffin or squirrel-cage fans to cool off their URR rigs. A general rule is to place these fans so that they draw off the hot air, as opposed to blowing air in over the tubes. Muffin fans show up at hanfests for $1 or so, and they are also available through most major electronics suppl iers. They have regained popularity with cmputer freaks, who use them to cool their

1chips. The only concern I can see is that this method of cooling might draw dust up into the rig. Anybody with more infomation on this, please share it with the group.

ANYONE OUT •THERE WHO •HAS ANY GENERAL KNOWLEDGE on the care and feeding of vacuum tubes

1(valves for our British audience) might want to write in and share it with your fellow surplus receiver fanatics. We have members who were born in the transistor age who could very well benefit frm the wisdm of those mong our group who cme out of the age of 1tubes, I guess l ^td have to say that my son cmes frm the age of IC’s.

Fran Walter Schivo cmes this tidbit concerning Increased audio gain. Walt jumpered temlnals 1+2, 2+3, 3+4 together to improve his audio. He said that with his particular receiver no noticeable change cane frm Jumpering pins 6+8 as discussed in previous toes . Could this mean a pre-surplus audio modlfication of sme sets? Anybody who t be able to explain th{s situation please write publishing central .

In a previous issue the membership expressed the desire to know just what the original market value of these wonderful radios might be. According to John Mohn the military carte out with a directive that ordered all “high-value” Items tagged with their “acquisition” value. John recalls seeing R-390A ^ts tagged at S2795, that’s in pre-inflation follars

(poss ibly up to t.en to one for you non-financier types). Patrick A. Mulreany purchased an R-389 from Davilyn Corp. that had an acquisition value tag of $3930. Matt Stutterheim bel ieves the cost to Uncle of the later R-390’s must have run much higher than these figures. So, it appears that these radios we hold so near and dear really are Cadil lacs and if we paid what the guvmint paid we could easily have bought a Cadil lac instead (but who would want to, right?) . Incidentally, the RACALs with which Uncle Sam is replacing the R-390A ^ts run around $9000. Which miqht explain an unsubstantiated rtrnor that a little man f rm the Navy has been running around to surplus outlets buying URR receivers for spare • parts.

Bil l Neil adds another figure to the price of a radio fpm a Department of the Army Technical Bulletin TB SIG 322-303, listing the 1960 price of an R-390 as $950. Sounds like a case of the goverment listing two prices depending on who sees the bill . Anyway, I am sure that others in our club will tell of other prices. That’s what this newsletter is all about, sharing all information so that we might be better informed.

And now, f rm that selfsame document suppl ied by Bil l Nei I we give you block diagrams of actual URR appl ications.

Pio eooco

000 PT APART

•otCE SIGNAL SPACE – DIVERSITY RECEtVtxe SYSTEM

( 5)

8’OCOANO RADIO TZLETVPZVRtTZR

TD 82.2-505-1

These diagrams lead me, and I am sure others, to wonder about just how one goes about wiring up a couple of URR’s for diversity reception. Chris Hansen has a couple of words to say about this. The major reason for diversity reception is that if one has two antennas spaced at a wide distance, each antenna feeding into its own receiver, chances are good that reception differences between the two antennas will cancel each other out, and produce a more readable signal with less fading overall . The type of receiver used on each antenna is imaterial , normal lye You may use two different receivers if you like. Sme warnings: Don’t try this unless you have a rather large back forty the antennas must be spaced 200 meters apart or more. Make sure that the two receivers you’re using are on opposite sides of your shack to minimize mixing of RF between the two receivers. Of course, this lets out diversity-DX unless you have very long arms or are willing to DX on one of the two receivers, running to the other one when you get a signal on the first and tuning the second receiver to the same t equency. You can feed the signals to the two sides of a stereo jack so that each ear s the signal frm one receiver only, and you can use your brain as the “mixer” .

also possible to construct a mixing arnpliffer or use a stereo amplifier (keep the treble and bass controls to the minimum setting) as a mixer. This method was devised as a way to help the military comunications system (especially the teletype setups) get better reception overall. The military gets away with it because most of the time our precious R-390 ¹s were set to one frequency for most of •their operational life and locked there. So put those pictures of frazzled privates running fran one receiver to the other at the behest of a calm cumunications officer out of your minds! The two receivers used in diversity reception were locked in place and Just had to be turned on (if they were indeed ever turned off! )

A QUESTION for the Users Group Book of Records. What is the most flights of stairs anyone has had to carry a military surplus URR receiver up? My personal record is three flights and I had to see the doctor after that. (I live on a fifth-floor walkup, and my R-390 is up there with me. However, I had help carrying the receiver up the stairs. Does that count? I suppose I ’11 have to carry it down smeday, though. I should get the truss now, I guess! Chris Hansen)

Larry Cohen (a non-manber, but I am working on him) regularly uses an R-390 the front panel of which was at one time sprayed with machine-gun bullets! How’s that for realism, fans??? ! ! !

THINGS OUR MEMBERSHIP IS LOOKING FOR DEPARTMENT on Musco, P.O. Box 118, Poquonock, CT 06064 needs a top cover for his R-390A.

m Kowalski is looking for a copy of the manual for the R-390 (not-A). He also has a copy of the manual for the R-389 that he will give away to the first taker who sends him a dol lar for postage. Jim’s address: P.O. Box 1181; Sebring, FL 33870.

(6)

OKAY GROUP, we opened a great can of worms by looking for the price of the R-390. Let’s open another can by trying to find out just how old these rigs are by their serial numbers . I am sure that if we can discover a few receivers’ birthdays in relation to their serial number we will give most of the club an idea of how old their particular receiver might be. Anyone with infomation, or for that matter, anything that might be of use to the group can send it to publishing central .

By the way, we could use a few more articles pertinent to the R-389 and the R-392. A lot of these rigs are in use, so please share what you’ve got with the group.

Craig Healy suggests that smeone start a “junkyard” for old URR rigs. What a qreat 1 idea! If anyone has the time or inclination we will be glad to advertise the effort right here in these pages.

Bob Lombardi says that CW selectivity is not quite as good as the wider bandwidths because the mechanical filters on the R-390A are not used. A single crystal is resonated with different loads to get the 0.1 and 1 kHz positions. The manual says that this is a 456 kHz crystal . Bob thinks it miqht be possible to make a crystal lattice filter with two or more of these crystals and thereby improve CW selectivity. A most interesting idea; does anyone want to try to tackle it???

THE R-390 USERS GROUP; P.O. BOX 421; MOUNT HOLLY, NJ 08060

PUBLISHER: SKIP AREY. TYPISr/EDITOR: CHRIS HANSEN

Al l articles and information shared through this users group may be reprinted only with pennission of the author. The publishing cmmittee assumes no responsibility for the accuracy or safety of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned in the paqes of this newsletter. The R-390 Users Group Newsletter is available at the cost of Sl per issue. Back issues are available through the publ isher at the cost of $1 per issue. An index will be publ ished of back issues in the first issue of future volumes.

THE NEXT PUBLISHING DATE IS THE WEEK OF DECEMBER 11, 1083. GET YOUR ARTICLES IN EARLY. YOUR CONTRIBUTIONS OF MATERIAL MAKE THIS NEWSLETTER POSSIBLE.

EDITOR’S NOTE: The mailing l ist (as well as the typing and information storaqe) of the R-390 Newsletter is now computeri zed. Check your mail inq label ; if corrections are 1 needed please send the label with corrections indicated to: CHRIS HANSEN, R-.39D NEWSLETTER, P.O. BOX 1226, MADISON SQUARE STATION, NEW YORK, NY 10159. The second number at the top of the label is your JD number; the first number is the issue number of the last issue on your membership. All those with a “3” in that space this issue are due to renew.

EHOLLOVV!• 4

NEWSLETTER

ADDRESS FOR SUBSCRIPTIONS: Chris Hansen; P.o. Box 1226; New York, NY 10159 EDITORIAL ADDRESS: Skip Arey; P.O. Box 421; Mount Holly, NJ 08060

SUBSCRIPTION PRICE: $4 for one year/four issues; $8 for two years/8 issues Back Issues: $1 each, issues available: 1 , 2, and 3.

WELCOME FRIENDS TO THE newest evolutionary step in our newsletter. We hat’e widened our hori zons f rm the “R390 Newsletter” to the “HOI low State Newsletter” Our humble journal will be encompassing all of the wonderful old tube-type receivers that you can think of, and their eternal operation through our shared efforts at reoair and restoration’. This change comes about through discussion with many of our newsletter participants. It seems we all have mutual needs for all our receivers as tubes become scarce and such. We are also shifting rs a tad on the publishing end. Chris has taken full charge of publishing tasks d ling the subscription list, finances, and final mailing. Skip will be doing the editing.

Henceforth, all money and queries concerning subscriptions and back issues should be directed to Chris, and all articles and infomation for the newsletter should be sent to Skip. This new situation should improve the quality of service for the future of the users group as we expand to take on other •tube type receivers. Consequently, we shall be seeking more articles and information on such rigs as the Hamarlunds, Hallicrafters, Nationals, HRO’s, and whatever else you have waming your shack. As we round out the first year of publishing we would like to thank everyone who has supported this effort thus far and, with your continued support, we will continue to have a newsletter of high quality far nto the future. WHO NEEDS TRANSISTORS WHEN YOU HAVE A GOOD WORKING TUBE RIG! ! !

Some of you have been asking about how to find me (WB2GHA) on the air. My station consists

1 of a Heath SB-300 and SB-400 (all tubes, of course) and I can usually be found on the

20 meter band, especially in the vicinity of the independent county hunters net: 14,336 kHz. I will also be operating HF mobile in the near future with a Heath HW-32A (Also all tubes).

1 Perhaps the biggest news to hit the pages of the tomb of tube-type wisdom comes from Radio West via Joe Bunyard. (Drum roll , please! ! ) AMPERITE, 600 Palisades, Union City, NO 07087 is once again producing the coveted 3TF7 tube. (Tah Dah!) Don’t that make yer day, Bunky?

DOES ANYBODY OUT THERE use the R392??? This is the mobile semi-equivalent of the R390.

It requires 24 volts at 6 mps, but is a really nice radio. I have seen a great many of than recently at Fwnfests for an average price of $150. They are sold by Fair Radio for between $135 and $200. It ^ts a sort of R390 built sideways.

T??? YOU NEVER HEARD OF A Q5er ⁷? Some of the fine old tube equipment can be -found wanting in the area of IF selectivity. A cheap and dirty way of solving this is to scour the surplus outlets for a gizmo called a BC-453. This is an aircraft receiver used during WW I l . It tunes too kHz through 550 kHz right across the 450 kHz IF. Now you’re getting the idea. You can also use a R-IIA receiver. Both of these rigs are available from Fair Radio Sales for about $15. They are not for the faint of heart, as you will need to construct a power

supply for its three voltages: 12, 24, and 250 VDC. Once you get this little box cooking you can either inductively couple it to your receiver or use a piece of coax with the shield connected to the case of both the BC-453 and your receiver, and the center conductor of the coax connected between the antenna post of the BC-453 and the other end wrapped a few times around the plate pin of the first IF anplifier tube. Ranember, this will only work on rigs with a 455 kHz first IF. You will have to experiment with the degree of coupl between the two. Some folks say the BC-453 works best with the plungers in its IF cans turned all the way out. What this lash-up does is, In effect, give the receiver an additional stage. This should be enough to get the hard-core experimenter warming up his soldering iron. More information on the Q5er can be obtained in almost any old ham radio handbook or circuit book written before 1965 or so. I found my Q5er with power supply all dressed up and ready to go at a hamfest. Because I recogni zed it for what it was and what it meant to the improved enjoyment of the receiver by the old-timer who was selling it, I got it for $5. It pays to be friendly at these activities.

ANOTHER HAMFEST, ANOTHER RELIABLE SOURCE for the various connectors for the backs of all surplus recei verse Mr. Joel Knoblock runs an outfit called: The RF Connection,

11707 Judy Place, Potmac, MD 20854; Phone (301) 299-5389. He currently stocks ALL, I repeat ALL of the connectors for the R390, R390A, R392, et al . The guy also has an incredible mind for which connectors go with which rig, so he can even help you out if you’re not quite sure what it is you need. His motto: “Mating is our specialty.” A great source.

CALLING ALL COLLINS EQUIPMENT USERS (This includes a great many URR receivers, including my own R390A. Collins is celébrating their 50th anniversary, and they are operating a special events station to celebrate. The special-events callsign is ADØC, and I have heard them on weekends in the General and Advanced portions of 20 and 40 meters. I worked them on 14278 kHz and AL, KPHWE, the station op, was glad to hear about the users group and our desire to keep old Collins gear alive. You can send anniversary greetings to ADØC, (⁹,611 ins Telecomunications, Products Division, Box 728, Cedar Rapids, IA 52498

Speaking of Collins being 50 years old, DICK TRUAX says that detemining the age of R390A ^tis as simple as looking at the date stamped on the filter capacitors C-606 and C-603 on the AF subchassis. They are generally stmped with a month and year, eg. 6-67. Also, you might look on C-103, the metal capacitor fastened to the back underside of the chassis behind the main PTO. You could also look on the crystal oven on-off switch S-106. Dick (and I, I might add) is interested in knowinq if anyone has an R390 bunt later than 1067. He has a spec sheet from Hamarlund dated 1970, so he feels either they were still making them or at least stocking them that late. Dick also lists the following cmpanies as suppliers of R300A’s: Collins, Electronics Assistance Corp. (aka Hamarlund), Imperial Electronics, Motorola,

Stewart-Warner (seems to be most of the earlier ones), AMELCO (merican F. lectronics Co.),

THE GALA TUBE SUPPLIER ISSUE brought two more sources out of the woodwork. From TODD ROBERTS comes: THOR ELECTRONICS CORP., P.O. BOX 707, LINDEN, NJ 07036, Telephone: (800) 526-4052 (in NJ (201) 486-3330 and in NY (212) 239-4510). I think I might do some recon work on this one myself. ed) Todd would also like to ranind you ballast-tube-seekers that the STF7 can be replaced with the 3TF4 and the 3HTF4. Also, fran DICK TRUAX comes yet another source: E.S.R.C., P.O. BOX 1192, DELRAY BEACH, FL 33447. Sme price examples: 6C4: $1; 6DC6: $2; 6AL5: $1. No 3TF7 ^ts/RT510’s.

HELP!! ! JORDAN ARNDT, A-306 Marlborough Drive, N.E. Calgary, AB, CANADA T2A 5M1 is looking for smeone who might be able to either service or supply a repl acement for the VFO of his R-390, I know we have a few menbers of the group who are adept at VFO info, so please write Jordan and help him wam the Canadian winter with a properly-tuning R390.

In my travels to various shrines of tube type radio seen manv a find old rig attacked by mildew, rust, yuck, et al . from prior use in a damp climate. This is especially true of sme surplus gear. Anyone with hints on the care and cure of such problems should shar it with the group. You can pick up sme mighty rank-looking stuff at flea markets, but if we could just learn f rm one another how to restore this stuff we will resurrect many a rusty rig.

SST HEY BUDDY. Ya wanna eliminate three tubes from your R.392? RUDOLF SALOMON supplies us with the following circuit that serves as a solid-state audio section, eliminating e 2 6AJ5’s and the 26A7GT (good riddance. huh?)

dolf says that the 1000 uf capacitor might be replaced with one of lesser value to revent “motor-boating” when the voltme is turned up. Also, in this modification you will need o repl ace the heaters of V606 and V607 with 82 ohm 5W resistors. The regulator and amp dissipate heat. This circuit works with 4 ohm or 600 ohm phones or speakers.

Now that we have expanded our horizons the “To Be Published” file is getting a mite thin. ease send all of your information about all the great old tube receivers to SKIP as soon as

ssible so we can make the expansion of our newsletter a successful one. All tips, hints, ideas, and dreams are needed at: P.O. Box 421, Mount Holly, NJ 08060.

ile it is getting a little cold to wander around the flea-market and hamfest circuit, u might take a little time this winter while warming yourself by the glow of your radio to ake up a checklist of the tube cmpliment Inside the aforementioned and all other rigs u might own. Making up such a list to take to your various tube sources will facilitate ur repl acements in the future. Sure, you might need a 3TF7 right now (like vour humble editor), but down the line you might just need that 6DC6, so stock up by knowing all you ed. MV tube-type hamgear uses the later COMPACTRON-type tubes. You know, the tiny squat es that take the place of two or three “old-fashioned” tubes. Well , I finding these ate-model tubes even harder to track down than some of the good old boys. I guess- it is cause they came out so late and so close to solid-state. I understand the really new anut-type tubes are all but impossible to track down. One good source is early-60’s v TV sets. I grew up two blocks frm TUNG-SOL industries. If I only had known then what ed now!

UBLISHER ^IS TUBE NOTE: Tom Farmerie, of 62 Sunrise Av., Grafton, MA 01519 (sometimes known as the Grafton Phantom Il) has • suggested that perhaps those of us who need tubes hould band together to pool our purchasing power. He has suggested that a Tube Buying onsortium should be formed. In line with the good old tradition of: “Don’t suggest it unless you’re will inq to run it ” Skip and I have charged Tm with finding out whether such a consortium is possible and then coordinating it. Our suggestion is that you should

Speaking of needing a 3TF7 it is time your tumble publisher-turned-editor added his two cents to the ballast tube repl acement controversy that cane out in previous issues. Okay, so the ballast tube went pffft! I did not have one handy (shame on me), but one of the repl acement schanes gets the rig back on the air UNTIL I can re-install the ballast tube as per spec, How’s that for standing on the middle of the fence and waving both ways! ! !

Sane people have been looking for power supplies to use with various surplus gear. As usual , 1

the best source seems to be FAIR RADIO SALES, 1010 East Eureka Street, P.O. Box 1105,

Lima, OH 45802, Incidently, if you’re not quite sure what your needs are you can call them at (419) 227-6573. They are glad to help,

In the January 1940 issue of RADIO magazine the New Hallicrafters S20R was selling for $49.50. This was such a stagger inq sum that Henry Radio offered it for $0.90 down and $3.49 per month. What would you pay for one of these now???

NOTES ON TUNING THE R390A, by H. Cornelius

The caments below are based on the BFO being properly zeroed so that the zero position on the knob corresponds to the exact center of the IF passband, To check this:

1. Set receiver to 2 kHz bandwith, full gain, with no antenna connected, and with BFO on. There should be a fairly loud rushing noise.

2. Turn the BFO PITCH knob back and forth. At one point, the rushing noise will be at its lowest pitch. If the BFO knob is not at zero, loosen the shaft couplinq behind the

1 1

make a list of your tube needs and send them to Tom, Tm will then try to find the best prices. When he does, you will be asked to forward your remittances and the tubes will then be ordered and shipped. Renenber, this is just a suggestion, so if you’re interested please contact Tom at the address above.

front panel and reset the knob to zero.

SSB TUNING: Set BANDWIDTH to 2 kHz, BFO to -1-1/2 (USB) or +1-1/2 (LSB) .

RATT TUNING: Set BANDWIDTH to 2 kHz, BFO to -2-1/2. Tune KILOCYCLE CHANGE knob for a nomal presentation on the RATT demodul ator, Special case: when copying narrow-shift RATT on a CV-89/URA-8 or a URA 17, set the BFO PITCH knob to -1. RATT is normally copied with the RF aain fully up and the AGC control on fast. If using limiter less denodulation, try FAST, MED, and SLOW settings for best results,

ALIGNMENT: The technical manual notwithstanding, an R390A can be aligned usinq only the calibrate signals and the LINE LEVEL meter, with the RF GAIN control retarded to keep the signal strength down. Use the calibrate points nearest the receiver dial readings called for in the alignment procedure, Do not overlook the first crystal oscillator tuning, T-207, which can be peaked for maximm on any frequency below 8 MHz. Do not attempt alignment of the 455 kHz I OF, transfomers, Perfomance of the three mixers varies considerably with various 6C4 tubes. If possible, try several In each socket and retain the tube qlvinq highest gain. Although the technical manual calls for 3 microvolt sensitivity, a wellmanicured R.390A will get down below 0.5 microvolt.

AN IMPORTANT POINT: The UNBALANCED input jack is at high impedance and works verv poorly with coax or with any but a very short antenna. The R390 will work well only through its balanced (two-pin) antenna input, with the antenna (center conductor of coax) connected to one pin and with the other pin connected to ground, This can be jury-rigged if necessary, but the best approach is through use of a connector designed for the purpose. A UG-970 or UG-971 connector will mate with the two-pin socket. The UG-971 adapts to a type C

connector such as the UG-709 (for RG-58/U cable) or UG-636 (for a UG-88/U BNC connector). The UG-970 adapts to the PI–259 UHF connector. In anv case, check the three connectors on the antenna relay box inside the R390 to be sure that each cable is made up to the correct ja

OES ANYBODY OUT THERF. KNOW ABOUT DYNAMO^TORS”? 1 have managed to avoid these thinqs like he plague throughout my radio hobby career and I can’t see any reason to learn about han now, but a areat many of our readers who might be us inq or experimenting with equipment requires dynamotors could use all the info you can supply. Please send al l of your mat ion about this subject and al l other stuff you have to share with your fellow Ube-travelers to SKIP.

I am sure more than a few of our members have faced replacing worn-out filter capacitors. ust what is your particular strategy for your particular radio? The metal “can” types nd plug-in types are getting pretty scarce. Since in many cases these parts have limited helf life, we need to know our possible alternatives.

The Most Diligent Subscriber Award goes to new member PETER CtJRRY who first overheard a ouple of hams talk inq about the newsletter on the air. Pete wrote one of these hams via he callbook address and came to find out that, after his long-distance information gathering, Skip lived only a few miles away from him. Glad to have you aboard, Pete!

ust a note that BARKER AND WILLIAMSON has discontinued its Q-multiplier and notch filter circuits for the Collins 75S1 (model 337-SI), and its circuit for the KW2/2a (model 340-A) i l l be discontinued when its current stock is depleted.

peaking of the KW?.A, your humble editor has been smacking his lips oveq this rig for a long time. I would very much like to acquire one or a KW2 (which can be converted into a A; more on this in future). If you have one for sale, or know someone who does, write me t Box 421, Mount Holly, NJ 08060.

THERE IS NO TRUTH TO THE RUMOR THAT SKIP decorates his Christmas Tree with old 6L5’s actually, use 25144′ s) .

OR SALE FOR SALE FOR SALE FOR SALE FOR SALE FOR SALE FOR SALE FOR SALE FOR SALE FOR SALE

X TRUAX, 3003 Gleeson Lane, Louisville, KY 40299, phone (502) 491-2871 evenings or weekends only, has the R.390A/URR

390A parts, all. are complete and operational unless noted otherwise. ‘JPS shippinq additional . All subchassis have been checked in fun operation they are complete except for ubes, which are comon types and readily avalable used or new.

ne Crystal Osci llator Subchassis, complete with al l crystals –

One Power Supply Subchassls• $60 ne RF Suhchassis, complete with all gearing, racks, and slugs, digital counter wo AF subchassis — $60 each

One IF subchassis LES.S BF() PTO and R and 16 mechanical filters only. All transformers intact stil l has 2 and 4 kHz filters $9D ne antenna relay assembly — $15

Two front panel grab handhes — $5 each ne front dial face w/window ne crystal oven HR-202 w/200 kHz and 17000 kHz crystals installed $25 ne PTO subchassis, complete with 6BA6 $60

One Oldham coupler assembly, all three pieces $20 for the set of three ne dial lock mechanism $5 ne zero-adjust mechanism One carrier level meter — $20

14iscel laneous parts include BFO switches, rear chassis oven switch, almost all front panel

tches and rheostats, the main wirinq harness MINUS a few connectors but largely intact, re 15.5 and 16 MHz crystals, and many other pieces of hardware including clamps, haft extenders, etc. Hard to find unless you dismantle an R390A as T have done. I have NO knobs or front panels.

I would prefer to sel l the subchassis complete rather than part them out, but would part out the IF subchassis for mechanical fi lters, transformers, couplers i f necessarv. Pri ces are not fixed wi l l ing to neqotiate on part or al l if interested in purchasing the entire package. Best offer takes i t al l r need the space it takes in my shack! ! ! !

LIN ROBERTSON, 036 Loping St. 1B, San Diego, CA 92109 has an series 97194-55 for sale. This set has been nicely restores in function, equipment, and aopearance. The outer chassis and front panel has been completely repainted in forest green; the front panel has been re-engraved and the engraving fi l led with white enamel . Comes complete with manuals, covers, spare fuses, and a box ful l of tested replacement tubes (NOT SUBS! ) . A lot of work and sweat has qone into this rig, including the Cornelius SSB mod. Am pl anning to travel and cannot (alas! ) take it with me. $600, we spl it shippinq costs. Telephone (61 Q) 483-121.9 anytime (not collect) or write to me at the the address above.

THE HOLLOW-STATE NEWSLETTER; CHRIS HANSEN; P.O. BOX 1226; SOtJARE STATION; NEW YORK, NY IDI

1 SHER: CHRIS HANSEN. EDITOR: SKIP ARFY

ADDRESS FOR EDITORIAL MATERIAL: SKIP ARE”; P.O. BOX 421; MOUNT HOLLY, NJ 08060

Al l articles and information shared through this users qroup may be reprinted on Iv with pemission of the author. The publishinq comittee assumes no responsibil ity for the accuracy or safety of untested modifications or the rel i abi l ity of suppliers of services, parts, or equipment mentioned i n the panes of thiS newsletter. The Hollow St.ate Newsletter is avai lable at t.he subscription price of $4 for one year, nr for two vpars.

Back issues are • avai lahle. through the publisher at $1 per issue (issues 1, 2, 3, and ¹1 are avai lable) . An index wi l l be published each year.

THE NEXT PUBLT.SHTNG DATE r.s THE WEEK OF MARCH 5, 1084. GET YOUR ARTICLES EARLY. YOUR CONTRIBUTIONS OF MATERIAL MAKE THIS NEWSLETTER POSSIBLE.

EDITOR’S NOTE: The mai l inq l ist (as well as the typinq and informat.ion storage) of the HOI low State Newsletter is now computeri zed. Check your mail ing l abel ; i f corrections ar needed please send the l abel with corrections indicated to: THE HOLLOW STATE NEWSLETTER; C/D CHRIS HANSEN; p.o. 1226, MADISON SQUARE STATION, NEW YORK, NY 101. ⁵9.

To find out when you are due for renewal , look on your address label ; you wi l l see the words : “SUB EXP # and a number. The number • is the issue number of your last issue. All those who have a “4” on their mailing label are due to renew with thi s issue. Those who see a “5” at. that place on their label are due to renew in March. By that time 1 wi l l a “LAST ISSIIE – PLEASE RENEW” stamp for vour envelooes.

ADDRESS FOR SUBSCRIPTIONS: Chris Hansen, P.o. Box 1226; New York, NY 10159

EDITORIAL ADDRESS : Skip Arey; P.O. Box 421; Mount Holly, NJ 08060

PRICE : $4 for one year/ four Issues; $8 for two years/ 8 issues; back issues are available at $1 apiece; currently available issues 1, 2, 3, and 4

MAKE CHECKS PAYABLE CHRIS HANSEN

WELCOME, FRENDS, TO THE EWSLETTER that instead of “daring to be different” strives to be exactly the same as things were around 20 or so years ago. It seems that the changeover to all-tube receivers has been widely accepted and our current membership is pushing the 100 mark. Thank you for making this possible through your continued support and your steady stream of information.

very important and somewhat scary piece of information comes to us from new member DICK ISONO Anyone out there who owns an R390A should take note as well as steps Go inside your IF-subchassis and check capacitor C-533. It is a mf paper unit that has a rather low voltage rating; {e frequently shorts out and (here’s the scary part, please read it sitting down) TAKES ‘NE >ECHANICAL FILTER USE OUT WITH IT! ! ! To compound matters Dick knows of one fellow R390A user who, discovering his set was dead, proceeded to switch to various bandwidths in an attempt to get audio, thereby popping ALL of the preClous (and terribly expensive) filters because C-533 had shorted out. Dick’s reconmendation is to replace C-533 with a 400 V or 600 V orange drop Mylar capacitor, I would go further and say that while you have the rig unracked tear in and get rid of all the paper capacitors, These types of capacitors deteriorate with age and (get this) lack of use, like sitting on a surplus store shelf for a whi lee Orange drops are made by Sprague and can be found at any radio-TV parts store or through many catalog sources. THIS TEE OF MODIFICATION IS APPLICABLE ’10 TUBE-TYPE RECEIVER WITH PAPER CAPACITORS IN IT. so, go over your schematics today. I have seen some really impressive modifications done in antique radios where they have taken the insides out of the paper cap and placed the usually smaller Mylar capacitor Inside the old paper capacitor case, thereby preserving the original appearance.

Incidentally, Dick Nelson represents Astronomy, Unlimited, 3470 Travis Ave., Simi Valley, CA 93063. Perhaps in future issues Dick might let us know if and how receivers of our favorite ilk are used by radio astronomers I saw a book on this subject once and found it fascinating. I think that book recomended the old Heath H-312 or some •such receiver. Anybody with any ideas send them in.

If you want to hear a lot of experienced people talking about tube-type gear PETER CURRY ecomends that you listen to the frequencies occupied by ham radio operators who are nto using AM, in contradistinction to most hams who use SSB. Pete says that you might try 1885 (160 M) nights, 3860-3890 (75 M) nights; 7290-7295 (40 M, daylight until wiped out by foreign broadcast stations), 14285 (20 M), approximately 9 PM EST weeknights, as well as

29000 kHz band around dinnertime when conditions permit. These AM frequencies are useful

to tube-type equipment users in that these folks tend to prefer using vintage equipment and spend a great deal of time talking about it, If you thought ham AM was dead Pete can prove otherwise, with over 500 loggings .

JOE BUNYARD reminds us of two tried and true methods of reading those faded-out tube numberse Method one is to put the tube in the freezer for a few minutes and then remove it and look at it quickly. The obvious caution in this case would be to allow the tube to return to room temperature before installing it or performing any tests on the tube. Too quick a change from cold to hot could fracture the envelope. Method two, and a very effective one too, is to dip the tube in plain old household —onia. This will usually bring the number right up. Some dyed-in-the-wool tube scroungers carry a small bottle of the stuff with them to hamfests and flea markets

AND row A NEW FEATURE (drumroll). Welcome to MEET TUBE, an in-depth investigation of a specific tube in connon use by all of us tube-set fans. This issue we gee to know and love

the ever-popular 6AU6 and 6AU6-A. The 6AU6 is a miniature-type tube used in radio equipment as an RF amplifier. It ‘is most often found in high-frequency, wide-band applications, but 1 It is occasionally used as a limiter tube in some FM equipment. What makes a 6AU6-A out of a 6AU6 Is the addition of a controlled heater warm-up time (usually around 11 seconds) for use in applications employing series-connected heater strings. The 6AU6 makes its home in a seven-pin miniature socket, and it can be operated In any position, making it desir- 1 able for portable and mobile applications. This tube can be found in applications with or without external shielding. In some cases, the external shield Is connected to the cathode. This will affect interelectrode capacitances when the tube Is used with a triode connection.’ Tubes of this type are most comonly referred to as “sharp cut-off pentodes

Filament voltage6 3 volts

Filament amps0 3

Capacitances uuf

C in5 5

C out5 0

6AU6

C gp0 0035

6AU6-A

Plate supply voltage250 volts

Grid bias 68 ohms

Screen voltage 150 volts

Screen ma

Plate resistance 1 megohm

Trans conductance 5200 micromhos

No substitution information available at this time but this is a coamon enough tube. Current prices range from Radio Shack’s current lifetime replacement price of $6.29 through Edlie 1 Electronics $2.45. Hamfest price is usually around $1.00,

Incidentally, a little-known service of your local Radio Shack (so little-known that you might ha I.e to remind the manager of It) is Radio Shack’s Tube Hotline. Radio Shack’s current catalog (page 121, in case you have to prove it to the manager) claims over 2000 tubes available. Also, all Radio Shacks ere supposed to have tube testers. These can be found in a back corner, usually, and you might want to bring a rag with you to dust it off before using it, However, special kudos must go to the Cherry Hill NJ RS store, as their Eube tester is prominantly displayed in the front of the store next to their fancy cmputer display, Some people can remember their roots, ya know.

We received a letter from a cmpany called the Windsource Co, P.O. Box 280, Wamsutter, WY, Owner Al Smith tells us that they specialize in radios from WLF through microwave. They stock parts as well as complete sets.

While involving myself in another un-radio-reiated activity I ran across a man who works for Powell Electronics, Inc. South Is land Road, Box 8765, Philadelphia, PA 19101, They are THE source for Amphenol, TRW, Kings, and SMA connectors. They stock all current and previous military connectors. They do, in fact, stock the connectors for the R390, R390A, and special applications connectors for conmand sets, et al. These are all NEW connectors They are knowledgeable In both civilian and military part numbers, so send them your want list.

FINAL WRD on the tube shield controversy cmes through DALLAS LANKFORD and his copy of

Amy Manual Nil-5820-358-20. This manual states that all tube shields except V201, V206, V505, and V701 can be removed. There does not appear to be any new leakage paths around the mechanical filters with any other tube shields removed,

o from Dallas comes this word about tube testers. They are notoriously unreliable for ecklng tubes. (Do they do anything else? pub.) Of bad, weak, and otherwise defective tubes I have tested on tube testers, about have tested good. The standard approach to tube replacement is replacing with a known good tube. Of course, there is a catch. You need an identical piece of equipment which is known to be in good operating condition. (There we go, I how have an excuse to talk my wife into a second R390A. ed) Fortunately, it usually suffices to replace one tube at a time until the problem goes away. The only case I have encountered where the one-tube-checked-at-a-time did not work was an HQ-180 which slowly lost AGC voltage (resulting in the S-meter reading S (+40 on almost all signals). The- problem was traced to two bad gain-controlled IF tubes. When this 180 was compared to my older 180 the AGC voltage on the older 180 was found to be less for stronger signals This problem was traced to the 455/60 kHz converter (which is gain-controlled). No change in S -meter readings was observed after correcting the problem, but strong signal handling performance noticeably improved. Perhaps the 180% reputation for overloading is undeserved.

‘Ihis might be a good place to note that we have on hand very few non-R390 articles for publication. For that matter, we are low on articles all the way round. We will need a lot more information If we are to keep from delaying publishing the next issue or substantially shortening it. You are the user group. Please send information on receivers, tubes, or what have you. Your humble editor also could use desperately up-to-date tube substitution data , Send all of the above to: Skip Arey, P.O. Box 421, Mount Holly, NJ 08060. The news letter you save may be your own.

ANYBODY GOT DATA ON OLD-STYLE CARBON MICROPHO>ES

AND live from the elegant Tube Room, high atop Skip Arey’s R390 rack, comes more E SUPPLIERS :

1 ler TV, 208 S. 2nd St., Augusta, AR 72006 sells used, carefully checked tubes Send $1.00 for catalog.

Elmira Electronics, Inc., P.O. Box 4320 SS Sta., Elmira, NY 14904 handles all Westinghouse tubes, ships within 24 hrs , and accepts personal checks. Tubes are guaranteed.

Rutan Electronic Sales Co. , 164 Mercer St., New York, NY 10012 handles RCA and GE tubes They do list the 6DC6, 3TF7, 25Z6, and even the discontinued 6BA7. You can call for current price data at (212) 334-9393.

Steirnetz Electronics, 7519 Maplewood Av., H—ond, IN 46324, phone (219) 931-9316. Send $1.00 for catalog.

Electronictown, Inc., 440 7th Av., Box 2048, San Diego, CA 92119, phone (714) 232-937.9

Electronictown (East Coast Store) 1617 South Main St. , Box 1000, Wilkes -Barre, PA 18703 phone (717) 824-7859.

Spencer Tubes , RD2, Box 24, Corning, NY 14830 specializes primarily In final amp tubes like the 6KD6, 6LF6, 6LQ6, 6JB6, etc. It sells matched pairs for such applications

Slep Electronics Co., Hwy. 441, Otto, NC 28763, phone (704) 524’7519 is a source for tubes and equipment. It’s almost as good as Fair Radio for most gear.

THIS hONTH’S TUBE EQUIPMENT SUPPLIER DATA CAME FROM JOE BUNYARD AND JOHN ARTHUR.

About half a dozen members wrote suggesting that I let everyone who is in love with Collins equipment in on this infomation. Some of you might recall that I mentioned in a previous issue that Collins was celebrating its 50th anniversary. Well, a fine book has been published about this fact called: “The First Fifty Years: A History of the Collins Radio Company and the Collins Division of Rockwell Collins It is available for $10 plus $2.75 shipping from: “Spectrum Association, Attn: Judy Jourdan, 105-161, 400 Collins Road, NE , Cedar Rapids , IA 52498. ^t‘

AMATTER, BUNKY, ya say ya can’t find a schematic or shop manual for your old Sky-Buddy receiver?? Ya say that even if you find a SAMS photofacts dealer who can supply one he wants your first-born child as payment? Well, take heart, friend. You need merely call the central branch of your nearest large city library. I found out that really big libraries often have a complete set of SRS photofacts, with xerox machines standing close by. So, make a few calls and you will no longer have to pay $14 for one sheet of paper (last quoted price for the Hallicrafters S-120 watch out! I once requested the photofact sheet on an esoteric piece of equipment from the Boston Public Library. They brought it out but would not allow me to xerox it I had to COPY IT BY HAND!! So, bring your straightedge, circle template, and lots of pencils with erasers. pub)

SO YOU KEEP SEEING OLD HEAN AROUND HAI.•EEStS without original manuals? Relief in the form of replacement manuals, parts, and technical support but a phone call away at (616) 982-3296. I must have called this number dozens of tiæs over the past few years and I have always received expert assistance. Once, whén tracking down some power supply data on a very old piece long since out of production, the technician helped me by supplying alter- • native power supply designs using updated components. nie folks at Heath are OK in my book.

From LARRY DAVIS cmes this problem and solution that R390 owners might face. “I ‘ve had a problem in my receiver since I first got it of low sensitivity on most bands below 8 MHz. I tried all the normal fixes in the first mixer and first crystal oscillator, and replaced nearly all the components in these circuits with no noted improvement. Finally, in desperatio I dragged the receiver to my job, where I have access to a spectr8D analyzer (some people have all the luck. ed). I used it to make relative gain checks throughout the front end. I found that I was getting 14db less signal the RF amplifier into V202 grid on 7 than I was getting to V203 grid on 8 (the normal sensitivity range). This was with all the tuned circuits properly tuned, of course, and I couldn’t find any failed components. The , problem of excessive loss was in the RF amplifier rather than the first mixer oscillator. If 1 you look carefully at Z204-2 (etc), the second tuned circuit in the RF amp plate circuit, you will see that the output of these to the next mixer is tapped-down from the maximum with two series capacitors (C240-2 and C241-2 in Z204-2) I found that by moving the line going 1 to the mixer grid (through S207) from pin 2 over to pin 3 (the ungrounded end of the 12 pf capacitor C321), the gain went up to a level similar to the bands over 8 I also did this to all the other under-8 bands with similar good results I can ^tt explain why I had to go to this extent to get normal sensitivity, but I suggest anyone with a similar problem’ might try this also.

Another hint from Larry is that a 6BA6 will substitute directly with the 6DC6 RF amplifier and will also give higher gain. You will have to run the RF gain lower for the same results , otherwise, it works well.

This admonishment concerning mercury-vapor rectifier tubes comes from JOE BUNYARD, Mercury Vapor Rectifier tubes such as #83, #816, #872, et al. should always be stored and handled in a vertical position. Before installing, apply voltage (5 V) only, for 30 minuees to one hour. will increase the tube life. If turned off, allow a minimum of 1 minute before turning on again.

Also from Joe this question. What does the suffix stand for in a tube name, e.g. 12AU7 WA. Joe saw this in some older radio ads and noted a higher price on such tubes. The only thing I can think of, Joe, is that it could be the equivalent of the “A’ ⁸designation 1 (see ‘”Meet the Tube^t‘ on page 2).

A number of you have asked about a tube-type amplifier for boosting an AM broadcast loop antenna. I have not been able to find any circuits that are directly designed for this purpose, but I did find an old junk box schematic that smeone drew up for a friend a number of years (about 15) ago. I must say up front that I have not tried this circuit, so perhaps one of the more adverturous members might want to give it a try. This circuit is inductively coupled to your present antenna circuit through L2, and please note that only the filaments are at chassis ground. WARNING: FAILURE ’10 ORRECTLY ASSE>BI.E THIS GROUND SCI-ma WILL RESULT IN A “I-DT” CHASSIS AND PASS UNWARIED VOLTAGE THROUGH COMPONENTS, RIG,

ANTENNAS, AND, WORST OF ALL, USER. DO NOT TO BUILD THIS IF YOU ARE NOT AN EXPERIENCED EXPERI>ENER FAMILIAR WITH SAFETY PROCEDURES. L2 is constructed by experimenti with a loop of 100 turns of #30 enueled wire configured into a loop sized roughly 2 x 5″.

(6)

FOR SALE: Allied SX-190, good condition (SWBC only) $135 + UPS Drake SW-4A, good condition (SWBC only) $125 + UPS

Dymek DR-33C Digital receiver (50 kHz – 30 >Nz), with extra Collins mechanical filters, rack mount, and cabinet both provided. $800

FRG7, damaged by fire but repaired by Yaesu and fitted with new cabinet, works great as backup receiver, however, ‘CDX’T position of filter doesn’t work despite $105 repair bill, $100 +UPS

Collins 51J4 with 3 and 6 kc filters (mechanical) in original Collins cabinet (1 kc filter missing) $300 + shipping.

All available from: Matt Stutterheim; 510 Main St.; Roosevelt Is land, NY 10044

(212) 838-5182 (answering machine)

Two ways to improve audio of the R390. First, from DICK NEISON. He suggests that good audio can be had by coming off the diode load terminal on the back of the set (14 or 15 on fB 103) through a .25 mf capacitor to an external audio system. Dick uses an old Dyna preamp and in conjunction with a good speaker. The second method is used by IARRY DAVIS. He built a synchronous detector and a 10-watt audio amplifier which is fed from the AF output jack on the receiver. ffle results are well worth the effort. The detector system used with the 8 kHz filter gives response nearly like on strong broadcast signals such as the BBC. circuit used comes from the April 1982 Popular Electronics. Your editor tried to get permission to reprint but could not, so you all will have to hit the local libraries for the schematic for this circuit.) Larry also says that it really does reduce fading distortion in SW and BCB stations. This is one I going to have to build myself.

next issue, especially for other receivers such as the HaÄarIunds and Hallicrafters rigs , So, if you don’t want to receive six pages of :’Meet the Tube please send your stuff post haste. Thanks for all the wonderful support to date. I confident it will continue into the future with our rigs of the past.

HOLLOW STATE >EWSLEffER, c/o HANSEN, P.o. BOX 1226, NEW ‘ORR , NY 10159

PUBLISHER: HANSEN EDINR: SKIP AREY

ADDRESS FOR EDITORIAL MATERIAL: SKIP AREY, P.o. BOX 421, HOLLY, NJ 08060

All articles and information shared through this newsletter may be reprinted only with permission of the author. The publishing comittee assumes no responsibility for the accuracy or safety of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned in the pages of this news letter. The HollÖw State Newsletter is available at the subscription price of $4 for one year, or $8 for two years. Back issues are available through the publisher at $1 per issue (issues one through five are available. 1

Saples are also available at the sae price (the most recent Issue will be sent). An inquiry sheet is available for a SSE.

NEXT PUBLISHmG DATE IS JUNE. GET ‘OUR ARTICLES EARLY, YOUR CONTRIBt.rt10NS OF THIS IEWSIÆTTER POSSIBLE.

PUBLIS%ER’S The mailing list only, now that I have moved to a different computer service bureau, Is (and that only for the next two months will be cmputerized)e However, check your mailing label If corrections are needed send the label to me at the New York address above, To find out when you are due for renewal, look on the envelope. If the stamped legend: ‘Last issue please renew’ appears, this is your last issue. Otherwise, look on your label you will see the words “SUB EXP and a number. The number is the issue number of your last issue (6 is June, 7 is September, 8 is December, 1984).

WHOLLOW

NEWSLETTER

ADDRESS FOR SUBSCRIPTIONS : Chris Hansen; P.o. Box 1226; New York, NY 10159

EDITORIAL ADDRESS : Skip Arey; P.o. Box 421; Mount Holly, NJ 08060

SUBSCRIPTION PRICES : Domestic and Canada /Mexico. . • $4 for four issues

$8 for eight issues Make checks pay- Other foreign: $8 for four issues, $16 for eight Issues able to: Back issues : $1 each USA/Canada/Mexico, $2 each other foreign; CHRIS HANSEN issues available: 1 through 5.

GREETINGS ONCE AGAIN, all you faithful followers of tube-type-tech. We are really becomIng a tidy little group, with new members who are also addicted to the warm glow of fine Id radios. But first, a word on the headline article from last issue. Many of you potted the problem with this article. The capacitor in question on the R-390 IF sub- chassis is C-553, not C-533 as reported! The origin of this typo may just go all the way back to Uncle Sam, because, as your intrepid editor performed this small modification I referred to my Army manual (TM 11-5820-358-35), pages 68-69. If you have this manual you will note that Figure 41 has the C-553 capacitor mislabeled as C-533. C-533 is really off in the BFO circuit someplace. George Mulfinger thought it was an April Fool’s joke, but many of our members picked up on the typo in addition to George, Our regular R-390 whiz DALI.AS LANKFORD takes DICK NELSON’s advice a step further, To begin with, Dallas suggests using a .01 1000v disc ceramic capacitor, although he notes that anything in the .01-,1 range with a voltage rating of 600v or better will do. Dallas goes on to note that there are actually two paths to ground one from one of the mechanical filters, and one from the ground of the trinmer caps, The ground from the mechanical filters was rerouted to the grounds of the trimmer caps, and the path from the trirmner caps to the chassis ground was replaced by one of the above-valued capacitors. The point of the modification as Dallas does it is that you now have two caps protecting the mechanical filters, so that if one cap shorts the other cap still protects the precious (and expensive) mechanical filter

While on the subject of mechanical filters, the new (red cover ßJS-84) Fair Radio Sales catalog lists “used-repairable mechanical filters” as well as new filters on page 27. 1 have never heard of repairing mechanical filters, so if any of our audience knows how to go about it, please send it along to HQ for the rest of us,

This Fair Radio Sales catalog is listing a special purchase of R-390As, used repairable $215 and checked $335. They also list the less-used but wonderful toy the R-392 for $135 used-repairable and $200 checked. You can get a copy of this catalog by writing to: .0. Box 1105, 1016 East Eureka Street, Lima, OH 45802.

is episode of PEET THE TUBE concerns schematic symbols old and new, Deep in the bowels of your editor’s mildewed collection live a number of circa-1940 RADIO magazines . You will note In the drawing an “old” way to draw tubes, and then the “new” more-conventional way. When I think over my rather meager understanding of tube theory, the “old” drawing seems to look more descriptive to me, Anyone who might the his tory of the evolueion of the schematic symbols for tubes might share it with the troops 1

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Ae a recent hamfest I ran across Joel Knob lock, the proprietor of R.F. Connection, which we plugged (no pun intended, I hope! ch) a few issues back, He was alazed ae the number of curious inquiries on your part, and

OLD NEW looks forward to meeting all your connector needs, He ‘s still at: Suite 11, 213 North Frederick Ave, , Gaithersburg,

MD 20877,

0-0-0

We have a new member who also has a business worth noting in our pages , Sue Coulter, 1000 West Columbus Ave., Space Il-A, Bakersfield, CA 93301. Sue runs Sue’s Radio Repair; she specializes in pre-1950 radios , She also, along with some colleagues, has access to between 6,000 and 8,000 tubes , Sue sent us a rather amus ing price list headed “Sumer Cook Out Goumet Menu Soæ of the “dishes” of interest are: “Salsa Picante: 5Y4, 5W4, 81, 80, and 5Z3 or 5V4 , . all 5 for $5.50 Zen. Tranny Heart: new 117Z6 or 117Z3 $4,00⁸‘ “Paella – ^tyeech ^t4 to 5 lbs. old boob-tube parts, many new in original boxes $4.00 There are more, so a SASE to Sue will get you a copy of this list. Sue also says that she and her partners will make a bid on any list of needs a HSN member sends them, so make up your list of needs and send it, with a SASE of course, to Sue at the address above, Also available are large electrolytic caps and many schematics ,

Do keep in mind that most of those who are willing to provide BN members with information and merchandise would appreciate SASE’s with any requests for reply,

From MARTIN STÆIL comes this word on tube testers, Martin agrees up to a point with DALIAS Lankford ‘s observation that tube testers are unreliable, Martin informs us that HICKOCK still manufactures very reliable tube testers, They have a lab mödel #539C, and a less expensive model +6000B. He notes that older models like the 600A and the 800 show up on the used market, and can be rigged to test almost any type tube by adding a CA-5 adapter still made by Hickock, mte reason for their reliability is ehat they have a line voltage adjustment which establishes a standard reference voltage applied eo the tube inder test regardless of variations in power line voltage. Also, the meter reading depends on a mutual conductance number measured in micromhos, which provides a more accurate gauge of tube status than the more traditional red-green face,

NEW 2.EMBER RICHARD DAVIS, 859 Helena Drive, Sunnyvale, CA 94087 is parting-out 6 R-390 receivers and 3 R-389 receivers , If anyone needs parts they should send a SASE with a list of needs, R-390A: no IF parts, some VFO, ail RE, some audio and power-supply, knobs, meters, hardware, R-389: all “top-side” parts, some bottom side, knobs, meters, panel, and chassis

TROOPS: THIS IS YOUR NEWSLETTER. IT IS NROUGH YOI.R CONSTANT STREAM OF. DATA THAT WE KEEP EVERYONE’S NEED FOR INFORMATION SATISFIED.

FOLLOWS AN ARTICLE ON R-390A/URR ALIGNCNT BY DALLAS LANKFORD.

R-390A/URR PTO ALIGNMENT

Dallas Lank ford

The purpose of these notes ig to describe an alignment procedure to achieve almost exact end point alignment of the R-390A KILOCYCIÆ CHANGE (PTO tuning) . This procedure is similar to the method described in NAVSHIP3 0967-063-2010, the navy maintenance manual published Aoril 15, 1970, but is simpler because it avoids dropping, the front panel. Thanks to Dick Truax for the cnacial simplification, and for his general comments about PTO alignment which I have incorporated into the method below.

( 1 ) PTO (VFO) Subchassis Removal WARNING! 2 1 8 Handle the PTO subchassis carefully to prevent damage or misalignment. To prevent misalignrnent, do not turn the PTO subchassxs shaft or the KILOCYCLE CHANGE shaft (either outside or inside the front panel) . To remove the PTO the R-390A is placed upside down. If the bottom dust cover is present, remove it. The PTO subchassis is in the center of the bottom three compartmentg. Locate the

Oldham coupler and remove the anti-backlash spring, gee Fig. 1 below. The Oldham coupler connects the PTO tuning shaft to the kilocycle change shaft. You will probably have to rotate the kilocycle change shaft with the front panel knob to bring the anti-backlash spring into a convenient position for removal. D9 not loosen the spline socket head screws. To remove the spring I use a small hemostat which is ideal for delicate work like this. (Hemostats are also useful for soldering and unsoldering work, holding small parts , and other tasks, and are sold through several supply catalogs and at larger electronic supply stores. Or if you know a doctor or nurse, they will probably give you one or two free, ) Put the spring in a safe place and do not lose it. Next rotate the kilocycle change knob until the Oldham coupler guide (the central disc) is in the position shown in Fig. 1 (when viewed from above). At this point, if you are the careless type, you should lock the KILOCYCLE CHANGE shaft with the front anel DIAL LOCK, Disconnect the blue plug P-109. (The metal cylindrical plug cover/lock mechanism rotates to unlock, and then the blue plug can be pulled out. If you cannot unplug P-109, examine the plug closely and make osure you have unlocked it.) Trace the white wire through the hole in the PTO compartment to the top side of the R-390A, unplug it from the RF subchassis (J 217) , and pass it through the hole in the PTO compartment.

oosen the three green Phillips head screws completely, and carefully lift out the PTO subchassis. Because of the positioning of the. Oldham coupler, and because you have locked the kilocycle change shaft, you must lift straight up, The coupler guide will probably fall free, but in any case remove the coupler guide and put it with the anti-backlash spring for safe keeping, PTO removal can also be accompkished with the R-390A on its side, ut it is not as easy to replace the coupler guide in that position.

PTO End Point Adjustment Cover Removal The location of the slotted x nut which covers the end point adjustment control is shown in Pig. 2 elow, Older PTO’s may not look exactly like Pig. 2 (some do not have the same shaped cut-out holes which give access to the slotted hex nut through the front bracket of the PTO) , but the position of the hex nut is the same in all models, With the appropriate size screw driver, remove the slotted ex nut, and place it with the anti-backlash spring and Oldham coupler guide,

PTO Subch s is Re acement Reverse the removal steps in step 1 above. Here if your PTO is a tight fit it may help to loosen (but do not remove) the two Phillips head screws that secure the triangular brack towards the rear of the PTO compartment, But to tighten these two screws firmly after replacement of the PTO requires either a flexible shaft Phillips screw driver or an offset Phillips screw driver with appropriate head size. These two screws can be gotten reasonably tight with a straight blade Phillips screw 1 driver angled past the flange of the triangular bracket, but do not use much pressure or you may strip the heads of the Phillips screws, Be careful when replacing the anti-backlash spring. A little grease

FIGURE 2 on the Oldham coupler guide may help hold it in place during replacement of the PTO subchassis. Again, a hemostat is very helpful for spring replacement. Make sure the spring ends seat properly in the grooves of the spring posts in the Oldham coupler. A close inspection with a flash light is probably a good idea.

NOTE: If the above preliminazv steps seem complicated, they are! PTO end point adjustment is not for the impatient or careless,

(24) !ZÆ……U.P Tum on the R-390A and let it warm up for at least an hour. I do not normally use my crystal ovens, but if you do, remember to tum them on with the switch on the rear panel. In some cases, an hour may not •be enough warm up time for an R-390A to stabalize, One of my R-390A’s seems to require 2 – 3 hours for stabalization, If in doubt, wait longer than the recommended one hour minimum,

100 KHZ Calibrator Ali ent Tune in WWI on one of its frequencies.

Tum on to zero beat with WWV. Turn NNCTION switch to CAL. A het with your 100 khz calibrator should be heard, With a 1

small screw driver or metal blade alignment tool, adjust C 310 through the access hole in the rear panel for zero beat. Do not change BFO PITCH setting from the above setting.

End Point Ad.iustment With MJNCTION switch set to CAI, and BF0 on

(and at the same BFO PITCH position as in step (5)), set KILOCYCLE dial to +000 (a het of the BFO with the 100 khz calibrator should be heard) , tighten the ZERO ADJ. knob, zero beat by turning the KILOCYCLE CHANGE knob, and release the ZERO ADJ. knob. Set the KILOCYCLE dial to 000 (the low end of the 1000 khz range). Again a het of the BPO• with calibrator should be heard Now comes the tricky part. Cut a plastic handled metal blade tipped alignment tool (Radio Shack 64-2223 or equivalent) to 3 3/16 inches long, see Fig. 3 below. The maintenance manual recommends using a non-metal ic aligunent tool, but I experienced no problems with my plastic handled metal tipped home-brewed tool, Slip the alignment tool through the holes in the 1 RP subchassis front plate and PTO front

3 3/16 bracket, and engage the end point adjustment control (slug) . Good lighting

FIGURE 3 is essential at first until you learn th ” feel” of proper engagement. I used a flash light to visually verify tha my aligynent tool properly engages the end point adjustment slug, You shou also be sure that your tool does not damage the threads which accept the end point cover nut, Some end point slugs can be tumed by hand, but mine was stiff, so I used needle nose pliers to rotate my alignment tool, About 3/4 inches of the plastic handle protruded past the front plate of the RF 1

ubchassis near the ten turn KILOCYCLE shaft stops for a good grip with the eedle nose pliers. In any case, turn the alignment tool (either clockwise nti-clockwise) until zero beat is obtained, My PTO was about 2 khz off the end points, and this initial adjustment required about turn. Next ne back to +000 (the other end of the 1000 khz range). Again, a het should e heard. Zero beat as before, using the ZERO ADJ. knob and KILOCYCLE

CHANGE knobs. Tune back to 000 and zero beat with the end point slug again. ternately repeat the +000 and 000 adjustments until no improvement is tained. After 5 or 6 passes, you should be within 50 hz or less. WARNING: Do not reverse the +000 and 000 steps during this procedure.

PTO End Point Ad •ustment Cover Re lacement Remove PTO subchassis as step 1 Replace slotted hex head nut refer to step (2) ) •

L (8) PTO Subchassis Replacement Refer to step (3) , NOTE, Before placing the PTO subchassis for the final time, inspect the Oldham coupler, and clean and re-lubricate if necessary. I often use 3-in-l oil, but you y want to use a heavier lubricant, I have also used a good quality icycle bearing grease before with excellent results.

MARKS: My first (and, until now, only) PTO aligirnent was done on a unit ich was about 2 khz off (1000 khz actual = 1002 dial reading) . End point libration was achieved with about rotation of the end point slug after or 6 alternations of the +000 and 000 adjustments. Neither of the two O ‘s I have experience with (one ali5ied by Dick Truax, and the other by

) are exactly linear throughout the 1000 khz range even though the two end points in both cases are almost exactly 1000 khz apart. After a thorou=h up, the R-390A I bought from Dick is as much as 200 hz off at 100 khz bration points between the end points, while my other R-390A is as much as 400 hz off. Such departures from linearity are common, and the maintenance nuals specify that linearity should be better than 300 hz when calibrated the nearest 100 khz calibration point. In both of my R-390A’s, linearity probably within 50 hz when calibrated at the nearest 100 khz point. In the PTO that I aligned, zero beat at 000 was obtained by rotating the end int adjustment slug clockwise (when viewed from the front) , I would like express my appreciation to Dick Truax for his patient explanations and discussions of PTO aligrxment. Without his advice and discussions, these tes would not have been possible.

The preceding article was originally published in the National Radio Club’s ‘tDX News , and is reprinted with permission of the author. ed)

ADDENDUM: Check the PTO tube before alignment, and replace, if necessary, before alignment. I learned this lesson the hard way by replacing the tube d tube shield after end point alignment, and then learned to my dismay that e change brought the PTO about 700 hz out of alignment.

REPE>BER, DEAR READER, how last issue we asked the mus {cal question: just what do those A” numbers mean??? Your editor received many variations on essentially the same theme, rhaps best described by SUE COULTER. ^t‘ Increasing use of radio in mobile installations showed a definite need for more rugged internal tube elements were manufactured of heavier r more rugged material. Some were specially treated in order to withstand greater overads, These tubes were termed ^truggedized, ^tand the letter “W” was added as a suffix.”

JAN Mini-tubes have “WA” which stands for sturdy construction with quick-heating ments. There, another mystery solved through your news letter.

NEW SCOTT FABRIS , 3626 Morrie Drive, San Jose, CA 95127 needs copies of pages 16, 17, 28-36, 114, 126 of Air Force Manual TO 31R1-2URR-442, and wishes to sell a Scott military receiver, and wants to buy a prewar Scott, Write to Scott for details ,

SKIP WES TRICH sent me a copy of the February 1971 issue of QST, and in it was an article that almost made your editor cry, It involves an account of the activities of Ralph McClintock KISCQ on the aftemoon of January 23, 1968. Ralph was stationed on board the U.S S . Pueblo when the North Koreans captured it, The article recounts how his shipmates and he had to take and fire axes to the ship’s R-390A’s and all of its other ‘ ‘juicy” equ ipment I am sure many of you have that field operations manual that describes how best to des troy your rig in time of eærgency, Very very chilling thought, I glad my rig is decormissioned because I don ‘t think l ^td have the heart.

AT THE REQUEST OF THE SHARP-EYED PUBLIS}ER, who tired of your editor’s childlike scrawl of schematics, I went in search of the ideal draftsman’s template for use in our journal, Very few are still around that have cutouts for tube work, but one nice one some of our members might like to purchase for their own use or for submitting schematics (although it is by no mea necessary because your editor has a tolerant eye) is the RAPIDES IGN #316 Missile and Space Electronics Template, Wow! Even the title conjures up images of old 1950’s sci-fi movies , With template in hand future issues should have much schematics to match our better printing process ,

JUST A SHORT NOTE once again thank all of the contributors in all of the past issues . 1 recently took a few days vacation and did a major teardown of my R-390 and performed no less than seven modifications, adjus tments, and Improvements, all made possible by our contributors, At this point it looks like I will have another half-dozen or so by my next maintenance s ession, Remember to keep articles about all types of tube receivers coming in to Editor’s Central we need articles on other receivers than the R-390, Any of you Hamarlund or Hallicrafters buffs •out there have something to offer? Please send it i.n pos chaste! ! !

PUBLISHER’S CORNER: Please take a moment now to check the mailing label on the envelope your HSN arrived in, If there are any typos, please tear out the label, correct the typo, and mail it to Publisher’s Central (P 00. Box 1226, New York, NY 10159), I am going back to the stone age xeroxed mailing labels instead of computer printed labels, Oh well, Members will note that the foreign rates have changed doubled, in fact. BSN is still a great buy at twice the price this proves it (hi ! ) , HSN has no advertising policy we do not take fees for printing information about suppliers, We would appreciate it if the members would contact us and recount the results of their contacts with suppliers mentioned in these pages, A STORY: When I first bought my R390, five years ago, it had no meters (like mose R390’s obtained from the government) I was shocked to find that a well-known supplier in New Jersey wanted $70 for the pair of meters I needed, When asked why the price was so high this source stated that inflation was rampant, didn’t I know? Well, I was resigned to being meter- less when my eye fell on a catalog of McGee Electronics in Ste Louis, They were advertising military-type meters, both audio level and signal level meters! I {mediately sent away and bought 10 of each, because the prices were $1,79 and 1,19 respectively! So much for inflation

THE HOLLOW STATE NEWSLETTER, c/o CHRIS uNSEN, P.o. BOX 1226, NEW YORK, NY 10159

PUBLISHER: HANSEN

EDITOR: SKIP AREY, P.o. BOX 421, IOUNT HOLLY, NJ 08060

All articles and information shared through this news letter may be reprinted only with permission of the author, The publishing comittee assumes no responsibility for the accuracy or safey of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned in the pages of this news letter, The Hollow State Newsletter is available at the subscription price of $1 for one year/ $8 for 2 years in US/Canada/Mexico, Back issues are available at $1 per issue. Foreign prices: $8 for 1 year, $16 for two years, back issues $2 a piece, Samples available for $1 US/CANADA/MEXICO and $2/FOREIGN, or 4 IRC’s. An inqu sheet is available for a SASE,

THE NEXT PUBLISHING DATE IS SEPTEPBER. GET YOUR ARTICLES IN EARLY. YOUR CONTRIBUTIONS OF MATERIAL THIS NEWSLETTER POSSIBLE.

EHOLLOW

: STATE LETTERNEWS-

ADDRESS FOR SUBSCRIPTIONS: Chris Hansen; P.o. Box 1226; New York, NY 10159

EDITORIAL ADDRESS : Skip Arey; P 00, Box 421; Mount Holly, NJ 08060

SUBSCRIPTION PRICES : Domestic and Canada/Mexico. . $4 for four issues

$8 for eight issues Make checks pay- Other foreign: $8 for four issues, $16 for eight issues able to: Back issues : $1 each USA/Canada/Mexico, $2 each other foreign;

WEICO>E ONCE AGAIN NEWSLETTER WITH TUBE-U-LAR OUTLOOK. !

AFRAD I must report that things appear to be fairly lean, material-wise, here at the Editor’s desk. Chris and I intend to continue to publish the best piece of vacuum tube based journalism that we can, but this will only be possible if you, the members , get more data, articles, and notes to us, Please help us out so that the Hollow State Newsletter continues to be everything that it now is

There! Now I can get down off my soap box and give you the data you need to keep your little tubes warmo

As many of you recall from our gala tube issue, your htmble editor receives catalogues from the various comercial outlets that stock new tubes for sale, • Well, ’tis ^tbout one whole year since we obtained the original data, and it appears from the most recent catalogues that prices, by and large, have remained stable, with only slight (10%) price increas es .except, of course, for rare or unique tubes. But, alas, there have been no particular price breaks on tubes e

Along these sæe lines, I about halfway through the hufest season and I encountering and tubes that are being priced as collectors’ items, as opposed to tubes to be used in regular service. Many more people seem to be buying tubes as collectables, albeit rather esoteric ones e (It ^ts like collecting glass insulators. ch) So, it appears that in future we will find ourselves in competition for these ‘ bottles

With this in mind I feel we must begin to seek out designs which will (sigh! ! ) allow us to replace tubes with FETs and such 0 So there! !! Having said it, your editor now throws down the gauntlet to our more technical types to search and peruse the data and literature to provide us with these circuits I have seen some fine surplus gear that engineering students have converted over to FETs as class projects I have even heard of (are you

Itt{ng down?) , “Solid-State R390s l” Is this possible? What I think all our readers would

00k forward to would be circuits that could be whipped up and essentially “plug” in in place of tubes. So, get cracking out there e I know from our membership list that the technical ability is out there in our ranks Besides, it might be just the shot in the am our newsletter needs

YO, BUDDY! (Philadelphia vernacular) You say you have encountered drifting in your recelver? mDD ROBERTS shares with us the following on a possible hollow-state cure for drift. Todd’s notion applies particularly to the R390s but can be used with any tubebased VFO or IMO, Todd cured the drift problem in his VFO by substituting several other 5749/6BA6W (Tube V 701 in the R390A) tubes each in place and noting how the receiver drifted during warm-up, He hit upon a “good” tube that shows very little drift during warm-up, His receiver drifts no more than 100 cycles from a cold start, So, if you have access to several of these tubes it might be worth trying each of them If your receiver drifts far beyond htman tolerance, Todd also applied the technique to his BFO and crystal calibrator tubes with equal success ,

I D.zst report a scrounging coup, I was walking between my office and my post office box one rainy day, and came across yet another old tube-type marine-band radio out in the trash. This one yielded ten 801 ‘s and the potential of building one serious q lifier for the low bands, Not to mention the fifteen odd standard tubes that are becoming harder to find, Also, my scrounging has produced no less than twenty 5-tube ‘ ‘kitchen radios , all loaded with goodies, That’s better than 1 radio per week. So practice getting really early on garbage days and take your doggie for a nice long walk, You could train the dog to pull a small wagon so you do not break any of your internal anatomical connections if you do run across an old marine radio. I am still not quite right from that wålk to my post office.

I owe DICK of ASTROIOMY UNLIMITED a bit of an apology because I missed out on some stuff he has to offer for sale to mubers of our group, Dick has what appears to be quite literally a ton of tube radios and parts to sell, including the following:

Eight long-wave tube sets, such as RBA, RBL, RAK, Æ/SRR-II, et al, All cover approximately 15-600 kHz, All are too heavy to ship

Many general coverage sets, including RBA and RBB sets, one of which even has a decal of the USS Hornet, which was sunk at the battle of Midway, The radio was out for servicing when the ship went down,

A whole lot of R-390 subassemblies, parts, filters, etc, A good stock of subminiature wire-lead tubes these are becoming hard to find,

..6DC6 :	1 tube , subs 6HQ6, 6HJ6, 6BJ6, 6GM6,
6c4w :	3 tubes , subs 6C4, 6C4WA, 6135, 6AB4, 6DS4.
5814A:	7 tubes , subs 5814, 5814WA, 6680, 7730, 12AU7, 12AU7A, 12AU7WA, 12AT7, 12AT7A,
5654 :	2 tubes , subs 5654W, 6AR5, 6AK5W, EF95, 6096. 12AT7WA,
5749 :	5 tubes , subs 6BA6, 6BA6W, EF93, 6660, 6HR6, 6AU6, 6AU6A, 6HS6.
6AK6 :	4 tubes , subs 6AU6, 6BA6, 6%.m6, 6HS6,	1
OA2	1 tube , subs OA2WA, 6073, 6626,
26Z5W:	2 tubes , no subs, see back issues of BN for diode circuit replaceents ,
3TF7 :	1 tube , subs 3TF4, 3TF4A, 3HTF4, RT-510, or one of the many modifications published

previously in %SNO

DOES ANYBODY now HOW ’10 REPLACE THESE TUBES WITH FET’S OR SOLD-STATE DEVICES??

Dick can be reached at 1-805-526-7066, or you can write him at 3470 Travis Ave, Simi Valley, CA 93063, A few issues back we asked people to track down substitutes for the tube compléments of various radios, mDD ROBERTS has provided us with tube substitution data for the R390A’s 9 different tubes, Total: 26 tubes , S tandard subs underlined.

SHARE THIS nrORMATION ‘I’mUGH THE STATE

WE COULD ALSO USE SUBSTITUTION HQ RIGS POPULAR TUBE RIGS .

Another supplier of surplus rigs has loomed over the horizon (my, what a terrible sentence!) N.E. LITCHE, P.O. BOX 191, CAuNDAIGUA, NY, phone 1-716-394-0148, They are sell-ing checked R390A ^fs for $250, CV-1982 SSB converters for $80,

3 MEET TIE TUBE this issue brings our first guest host, Sue Coulter, In addition to clueing your editor in to the incredients of Paella, Sue is mæ t mindful of fine old tube agræs and even knows of the old drawings that omitted the outside circle. There are so y that it is little wonder that those who grew up in the days of 2N222’s do not recognize em. For your consideration we present four tube symbol exhibits (A) is a symbol used by AT.T. AERICAN for a 171-A. (B) is what you will see • if you are looking at a dog-eared schem ^atic which includes a THOMÆ EDISON 224-A. (C) comes from the symbol for a RADIOLA 280 (where are companies like Radiola when ve really need them?) , and (D) is a PHIIADLPHIA STORAGE BAEERY C02QANY 224-A. sue also included many more designs, which we will share in future Issues She ruinds as of a great book called SAGA OF VACUU,f TUBE, available through SAS BOOß. It’s not just a dry history book, but includes many pictures and anecdotes. For it seæs that Edison had developed a grid tube, but didn’t it, because he was too busy developing the light bulb. Just think of it, folks. We co Id all be listening to radio in the dark. This is progress???

One of our toops (what is a toop, Skip? Is it like a Camper? ch), Mike Harla, 158 West Maplewood Avenue, Philadelphia, PA 19144 picked up a R390A filter from Radio West, Lucky for him, but he can ^tt figure it out In terms of input or output. He also needs the resonating capacitance. The type is F455 N40, ser, is 4V2, P/N: 526 9160 009, This is not the first question we have received concerning’ the use and abuse of Collins filters. Can anybody out there give Mike a hand, and would someone write up a simple technical article on possible uses of the mechanical filter???

Fellow traveler KEN ZICHI, 2001 S. Huron Pky, #12, Ann Arbor, MI 48104 has access to all the Sams plain number schematics and the Rider’s manuals, Just send KEN a SSE and $1 and he will copy away and refund any excess If you just need the schematic send the SASE and 20C (or a stamp), Also, Ken is looking for a way to hook up an S-meter to a Hallicrafters S-40A, If you help Ken out with this, send us a copy and we’ 11 share it with everyone else in the group !

BILL BAIIEY has inforæd us that when the 26Z5 tubes failed in military applications, they used plug-in solid-state substitutes. They worked with no additional modifications. (yep , right In the Ol ^ttube socket, Bunkey!). They carried such ID numbers as ED5902, EDI 8033, and STR,ST26Z5W , 7942, To Bill’s knowledge there Is no civilian supplier of these goodies. If anyone has these In their sets or can shed some more light on this please let your fellow users know. Your ht.i.mble editor has been getting a teeny bit of arcing in his R390 power supply during warm-up since I made the diode and résistor substitution, so I am very curious about these items, or a cure for my heart—wrenching buzzes, for that matter.

We couldn’t let an Issue go by without the help of DN.LÆ IÆmRD. Dallas would us that tube socket resistances and voltages can only be used to trouble-shoot if the resis- tance and voltage tables are correct. He notes that this is not the case for later model HQ-180’s and 180A^ts. One thing that should be done is to check the tube socket resistances and voltages of en actual unit in good operating condition to determine whether the tables in the manual are correct, Otherwise, you could spend a lot of time trying to figure out what is wrong with your unit using this approach, By the way, in addition to what Dallas says here, it might be wise to check the readings and calibration of your own personal ^TOM. It would seem to be a good idea to check your rigs out with your meter to see what deviations from normal your VOM shows , (I hope that made sense and did not de- 1 tract. from Dallas’ sa).

WAY>E HEINEN has just one thing to say to all of us: BEWARE OF CLOTH! It seens that a recent firing up of his HQ129X led hi-m to discover a problem he had not dealt with, but which all of us will experience at some tiæ. The cloth .wire insulation will give way, especially around the pilot light sockets and gromnetted holes, This will happen especially in dry environments , Smoke shorts and frustration may be avoided by checking these areas and any cloth covered wiring upon acquiring an old receiver, and of course before firing It up, lest you fire it up most literally! ! !

By the way, Wayne sees to It that the Hollow State Newsletter gets out acrQss the Medium Wave Interlude section of HCJB’s DX Party Line. If you can’t receive HCJB see if your radio’s plugged in, Fillings have been known to work also.)

INTERMITTENr WEAK/LOSS OF RECEPTION is sue Coulter’s subject. Do you have an old tuber 1 which plays great when first turned on, but fades in a few minutes? You check obvious

&lings like the line cord, antenna, ground connections, and wiggle the tubes around, Nothing is wrong what next?? One clue may indicate the next move: does it fade and stay quiet, or does it come back on briefly only to fade again? This on-again, off-again syndrome may be a defective tube whose filaments open when hot and silence the receiver, then cool down and unite again, turning the receiver back on. Tine the cycle, then put each tube in a tube tes ter and leave it under test for this length of time or longer before deciding it’s OK. If working in a cool room, invert an ordinary drinking glass over the tube to simulate heat conditions inside the set’s cabinet (that should freak out the local Radio Shac sa).

Sets that fade and stay weak or silent until another electrical device on the same circuit is cut off or on most probably have intermittent coupling or b.ypass capacitors. A sæll surge in line voltage causes an arc over a poor connection and restores it temporarily, The set will suddenly gain volume, but fade again,

If you haven’t already replaced the original paper capacitors, now is the time. Do not forget to check the resistors as well, Replace any that deviate from tolerance percentage. Beware of bargain capacitors; if you must use them, check them with a good meter ch as the SPRAGUE TEL or a similar apparatus. Do not use a ‘0M to test leakage. se test equipment capable of submitting them to the 450-1000 VDC they must endure in a radio.

When replacing a component, it Is best to remove all leads from the terminal, clean off the old solder, and resolder as if you were just assembling from scratch. The routine use of lap joints Is sloppy technique, but there are two places where such joints might be best. This depends upon soldering equipment available, i ed., use only fine-pointed, relatively cool irons on lugs attached to wax-covered coils. Use a very large blunt taper straight iron to make chassis grounds: involving puddles of solder. The heat radiated by a large iron or gun can loosen the windings of small coils In a tightly-packed assembly and render them useless or incapable of holding alignment. A small or medium-size iron cannot heat a chassis sufficiently to produce a good bond covering a half-inch or larger surface. Therefore, in the absence of these tools, Sue suggests cutting the old lead or even from the original joint and making a hooked lap : , and crimping the hooks before soldering.

If the capacitors have been replaced before the intermittent behavior started, try reheatIng the solder joints. Touch up original factory joints that may have been poorly done or have cracked.

One hopes that tube testing, C & R replacement, and retouching of soldered connections will cure the intermittent condition. If it does not then prepare to spend some time with a can of coötant spray.

SPEAKING OF SOIDERING, DALLAS LANKFORD supplies these data on soldering and unsolding.

If you own an older tube-type receiver, chances are that it has had some work done on it. d, I have observed that In some cases the soldering was not well done, Here are some ps I ‘ve developed through experience. If a solder joint looks different from others in the unit with a similar solder lug and similar of wires, it may be poorly done. For unsoldering I use Chem-wik Radio Shack and other types of desoldering braid do not work nearly as well. My iron is a 45-watt unit with steel-plated tip. Copper tips are fine if you clean them regularly, and occasionally file the tip. To unsolder, apply the Chem-wik braid to the joint, and touch the iron to the braid. When the solder melts it is sucked up by the wick. For solder joints with lots of solder, cut off the end of the wick and repeat as many times as necessary to all the solder. If the wires become loose or fall off the lug as the solder melts, it Is definitely a bad solder joint. Many times a bad joint can be redone without cutting the leads and starting over. Dental probes, hemostats, and needle-nose pliers are useful for recrimping loose wires securely eo solder lugs. Only after the wires are firmly attached to the lub is solder applied.

Correct technique Is to apply the iron tip to the lug and solder (rosin core) nearly but not on the tip itself. I often apply a little solder to the tip to improve heat conduction to the joint. If wires must be removed from a lug, dental probes and hemostats are essential. (Note: a hemostat is a medical clamp, something like a flat-tipped scissor-like tool that locks closed. Your local medical supply house will have them In profusion, and many Radio Shacks et al. also not stock them. ch) Even with care, wires must someti.æs be cut (as near the lug as possible) and re-stripped. Stranded hook-up wire (used extengively in most receivers) is difficult to unsolder because the strands break easily, and It retains solder, which makes re-inserting and re-crimping difficult. When extra length Is not available, as might be the case in line or RF-ga1n replacement, one solution Is to firmly wrap the wire ends together with #22 solid wire, which is in turn attached firmly to the lub and then soldered. In other cases, splicing works nicely. Twist the wires ogether firmly and solder (see lap-joint above. ed) A small insulated crimp connector an be s 1 {d over the joint and crimped. Taping solder joints together Is not for insulation because tape ages poorly.

If you have doubts about how a good solder joint is made, unsolder a few in your receiver and look closely at how the wires are crimped around the luge in their HQ-170s and HQ-180s occasionally “float” one end of a component (resistor, capacitor, et al,) ,

For one end of a resistor is merely stuck through a solder lug hole. Such an arrangement Is really poor wiring practice, but works when the other end of the component Is firmly attached and soldered first, and tension is used to hold the floating end against the lug.

Well, Campers, that wraps up all ve have for this round. We really need a great deal of material, especially stuff that takes us beyond the R390. It may be my favorite receiver, but I also use an HQ-180, and I sure would like to learn about its innards. PLEÆE (just imagine your humble editor down on his before his Sears Comunicator 11 mill). Send in more infomat{on, articles, circuits, Meet the Bubes, anecdotes ( 1 ⁸m not the only funny person, you know), tube complements, Solid state (ouch) replacements, and anything else appropriate for BSN. The publisher will give a free year’s subscription to the best NEW contributor (in his and my judgment) next Issue. See you in 3 months . Skip

PUBLISER’S CORNER, This issue is late because your publisher came down first with tonsil-

litis, and then with an affliction known as Bell’s Palsy (partial facial paralysis left side only) I lost 20 pounds in a week because of the discomfort. I don’t need that weight, but it was a shock nonetheless. The Bell’s Palsy will pass within two months, but the throat has improved muchly, tfianks

Just as a matter of record, issues 1 through 4 of HSN/R-390 Newsletter are out of print for the moment. Perhaps next year we will reprint those issues, Those who ordered back issues along with subscriptions have had their subs extended those who only ordered back Issues have had their checks returned, with apologies

1 1

I would like to second Skip’s plea for more material. You should hear him he’s a shadow of his former self pining away because he wants more material from you, the readers (h Serious ly, folks, a few people are supporting us well now we’d like to hear from all 0 you. As was mentioned above, the NEW contributor of the best tidbit/ article in December’s HSN will get a free one-y.ear extension of his/her subscription.

HOLLOW STATE NEWSLETTER, c/o CHRIS HANSEN, P.o. BOX 1226, YORK, NY 10159

PUBLISHER: c1-m1S EDITOR: SKIP N.EY 1

ADDRESS FOR EDITORIAL MATERIAL: SKIP AREY, P.o. BOX 421, PDUNT HOLLY, NJ 08060

All articles and information shared through this news letter may be reprinted only with • permiss ion of the author. The publishing comittee assumes no respons {bility for the accuracy or safety of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned in the pages of this newsletter. The Hollow State News letter Is available at the subscription price of $4 for one year, or $8 for two years, Back issues are available through the publisher at $1 per issue (issues 5-7 are available). Samples are available at the same price (the most recent Issue will be sent) Inquiry sheets are available for a SASE, The above prices are for US/Canada/Mexico res ident8. of other 1

countries should double each price $8 for one year, $16 for two, back issues $2, samples $2 or 4 IRCs. Inquiry sheets available for 4 IRCs .

TIE NEXT PUBLISHING DATE r.s DECQBER/JANUARY (N AVOD THE CERISTMAS RUSH). YOUR CONTRIBUTIONS OF MATERIAL MAKE THIS NEWSLETTER POSSIBLE.

SUBSCRIBERS NOTE: Check your mailing label if corrections are needed send the corrected label to the publisher at the New York address above, To find out when you are due for renewal, look on the envelope. If the stamped legend: ‘Last issue please renew’ appears , this is your last issue. Otherwise, look on your label you will see the words “SIJB EE and a number. The number is the issue number of your last Issue (8 is December/ January, 9 Is March 1985, 10 Is June 1985, etc.) Thank you.

±HOLLOW

NEWSLETTER

DRESS FOR SUBSCRIPTIOE: Chris Hansen, P.o. Box 1226, New York, NY 10159

110RIAL ADDRESS : Skip Arey, P.o. Box 421, Mount Holly, NJ 08060

SCRIPT ION PRICES: Domestic/Canada/Mexico: $4 for four issues, $8 for eight issues Other foreign: $8 for four issues, $16 for eight issues

Back issues: $1 each USA/Can/Mex, $2 each other foreign (+5-7 available) Please make checks (U.S. funds only) payable to HAISEN

ID ONCE AGAIN, A HAPPY HOLIDAY SEASON TO YOU ALL. Am 1 the only person in the world who corates his shack Christmas tree with TUBES?? First, the news. The new 1985 AR.RL Handbook is out, and when compared to my 1964 edition, it is quite aazing. The 1964 edi tion is almost Äusive1y tubes and tube circuits, with tons of data about our little glass-enclosed friends, Wi985 Handbook contains a mere one and one-quarter on a Sü(GI..E PACE (out of hundreds of pages). There are no references to receiving tubes at all. So it goes. Still, it is a ndy book to have to learn about electronics; you will be even happier if you chase down a pre65 edition at a I recently located a 1965 ALLIED (that’s pre—Radio Shack fot you unger folks) Electronics Data handbook, cover price $0.75. My tube friends and I read it only after midnight in a circle gathered around the light from an overdriven 6AU6, But, I waxing stalgic, and I want to save that for >EET TUBE. Excelsior, . .

r first tidbit comes frm JOHN SC%QÆIZER, WB5WRW (who owns a 1966 Allied Radio Tube Substitution list there I go again). John tells us that some older tube socket contacts may have idized over the years, giving non-linear contact resistances. Unusu•al R.F. and I OF. æplifier cillations often result from this oxidation. The offending tube can be identified by wiggling each tube slightly. A little contact cleaner sprayed into the socket is a quick solution; more rmanent results can be had by soaking a toothpick in the cleaner and wiping the insides of the neacts, but care muse be taken not to spread the contacts apart so that the spring pressure lost.

wm•ER OF THE NEW CONTRIBUTOR CONTEST IS (drum roll please) EDWARD MC FADDEN, who sent us, ong with many items you will see in future Issues, this tale about his tube receiver:

. Just over 3 years ago, I purchased a used Hamarlund HQ-180AC receiver from an individual the great State of Iowa. Upon receiving the set from the UPS delivery service, I t about examining it for any problems. Fortunately, there was very little wrong with the set her than dirt inside and out, and its need of alignment. After a few weeks use, I decided I could use a new set of tubes for It, as the BCB DX season was already upon us So, I ordered set of new tubes from Lindal Tube and Transistor Company in New Jersey. I had to buy a RCA

2 as Lindal didn’t list that tube on their order form. Shortly after installation of the new s and several hours of burn-in time before tweaking up the alignment, I noticed a problem. el led burning carbon and heard an arcing and sizzling sound, As I turned the RF gain pot unterclockvise, I noted the problem ending. I realized that by turning the

RF gain pots ccw, that more resistance was being introduced into the cathode circuit of the 6BZ6 RF amplifier tube, and that the RF gain pot had to be handling more voltage than it was intended to, Unfortunately, I didn’t realize all of this quite quick enough, as permanent and unrepairable damage had already occurred to the pot, Upon examining the underside of the chassis, I noticed a 2-watt resistor (R-18 47KO) hidden under the IF trans for^amer was burne up, and the 10K pot of the dual IW15K RF gain control also burned up. Upon replacing these 2 parts I fired the set up again, The new 2-w itt resistor began eo warm up quite quickly, so I turned the set off. I pulled the 6BZ6 RE tube and replaced it with the original tube

the set came with. The 2-watt resistor appeared normal when I fired it up this time, I tried the other 6BZ6 from Lindal that I had installed in the crystal calibrator circuit. 1 turned the set on for a few moments and, 10 and behold, the resistor had already begun to smoke , I had no 4-watt 47K resistors, so I soldered 4 1-watts in a series parallel configuration equal to one 4-watt 47K, Now I couldn’t fit all this into the space available, so I soldered leads to the points where the resistor was attached, and brought them out to the far side of the place where the shaft passes underneath, ,

(it is well known that tubes often vafy somewhat in characteristics and quality; a visit to your local Radio Shack with its tube tes ter might reveal what’s wrong with the two 6BZ6’s, ch)

From WILL MARTIN comes this observation: “Anyone who works on SW receivers needs an RF signal generator. Traditionally, these have been relatively elaborate and expens ive devices, because they needed not only stability, but also an accurate dial mechanism for frequency readout, The advent in recent years of the digital frequency meter, often at very reasonable prices of less than $100, has made the need for fancy dials or accurate calibration superfluous on a signal generator; the operator can easily put a frequency æter in the test circuit and read the frequency exactly,

“Therefore, why has no company come out with a low-cost (under $100) RF signal generator?

It should be no more expensive to nake a good RF signal generator than it is to make a decent AM radio, Anybody have an answer??”

Publisher: “Well, I suppose the answer is this: there is really a bigger market for AM radios than there is for RF signal generators , I would guess that if we comission a market resear company to do research on this market, come up with conclusions, and present them to a manu• facture r, they might be swayed into putting one out. Most of the market is with repairmen and amateurs/SWL’s/tinkerers. Most have their own setups now with or without a frequency meter, Perhaps the solution is a very low cost frequency meter advertised as being compatible with everything electronic, and sell that to all the people who now have an RF signal generator with a dial readout?

In the spirit of international relations we share this letter from FRITZ BRUNS , DC8XA, 1 Stupfstr.2, D-8 Munich 19, Federal Republic of Germany; “Hundreds of 0M’ s and SWL ^ts in Germany own R390A’s, R388’s, and R392 ^ts, I have been an R390 owner for two months now. It is an old one that needs some technical polish, Of course, repair parts are not available here. 1 1 need some parts for the reconstruction of my R390A, and• some spare parts , 1) VFO, complete (6BA6W/5749W). 2) Line level meter, 3) Crystal oven w/ crystals 0.2 & 17mc, 4) Top and bottom dust covers 5) condensers 2x 45uf, 3x 30 uf, 300 VDC. 6) Technical manual, and 7) SSB converter If anyone can help Fritz, please write him at the above address, Including the prices, and possibly some discussion of shipping arrangements , I have this image in my mind of one of our members trying to cræ a rack-mounted SSB converter into a Coca-Cola bottle while checking out a map of the Gulf Stream currents.

YOUR HUMBLE EDITOR HAS RECENTLY RECEIVED Catalogue Supplæents WS-84 from Fair Radio Sales, 1016 East Eureka Street, P.O. Box 1105, Lima, OH 45802, If you are an R390 owner you cannot last another day without the supplement, They list not only the rig itself at competitive 1 rates but spare upon spare upon spare, all at reasonable rates (Hi, boys and girls, can you say ‘Slug Racks and Springs, only $3.00′?) I called out to lima recently, and they assure me that they can meet many of the parts needs of R390 and R388 owners well into the future.

Also, they are glad to accept your calls concerning your particular needs at (419) 227-6573,

AYNE }EINEN has something to relate to us all concerning GAR-AGE SALE SCROUNGING, Wayne tells us to Never Overlook the Not Too Obvious, . oa used Heathkit VNM with a busted case yielded p a 12AU7, 12AT7, and a 6AL5, all good and all for $2.00 (total). A used and abused reel-toeel tape recorder (Wollensak) got Wayne a variety of tubes, 12AT7s and 12AU7s among them, for $1.00. Along with the older and AM/FM radios that don’t work, these items appear ularly at prices that save money on spare tubes’ Wayne also says not to be too quick to trip these old sets. Wayne collects old production model radios (an addiction he shares ith your humble editor). He hits the garage sales for the occasional real find, for example, an RCA 5X model, circa 1936 for only $5.00. (He, I saw a few old Art Deco AM radios with akelite cases (remember Bakelite??? You’re getting old!) selling in a flea market next to he Post Office where P.O. Box 1226 hangs out for more than $100 each! ! eh),

By the way, don’t forget to tune your vintage tube-type shortwave rigs to HCJB for Wayne’s rogram, Medium Wave Interlude, on DX Party Line once a month or so

ALI.AS LANKFORD has rethought some of his thoughts on soldering, so we ^t11 share them with •you. Dallas changed his mind about using steel-plated soldering iron tips. Radio Shack’s steel tip us ted internally, and welded itself to the heating element. After buying a spare heating lement, force was necessary to remove the old steel tip, naturally damaging the element.

Of course, one could only diagnose the problem after removal. Anyway, Dallas uses only copper ips now. They periodically have to be cleaned, reshaped, and retinned, but they don’t corrode-weld’ to the threads of your heating element. . Be looking in future issues for a number of Dallas Lankford’s excellent articles on the R390 and HQ180,

WE TAIX??? A number of our well-intentioned members have sent xerox copies of articles aken from other publications, mainly comercial. All the club bulletins , newsletters, et al. have long operated on the basis of free permission to copy each other’s aterial with proper credit given. We do this, and our sister publications do this with our aterial, However, comercially published material such as that found in QST, CQ, Ha Radio, nd even in out-of-print magazines such as the much-missed Electronics Illustrated, are protected by copyright law. In some cases we are trying to locate the author for permission to

Ish his article; we cannot publish without it. This may seem to some of you,

I must relate that some of your humble editor’s comercially-publishéd material has been reprinted without permission, and it Is not pleasant or courteous I have also had to deal ith individuals breaking the “code of credit” that makes sharing among hobby publications ossible; that is sad and a hassle. I thank each and every one of you who have sent articles in, and I assure you that we are making every effort to get permission to publish some of hese articles. But, it is a simple fact that respect for an author’s material is always the est policy. End of harangue; off the soap box.

JOE BUNYÆ..D has some data to add to the tube substitution list for the R390 that mDD ROBERTS ave us in issue #7:

or: 6DC6, substitute 6BJ6A (Mil.) or 6662; for 6C4, sub 6100; for 5814A, sub 7316, 6B 6189, 189, 6067; for 5654/6AK5, sub. 5591, GB 408A, 6028, 6968; for 6AK6, sub GB 5136, 7543; for

OA2, sub. 6830. Joe goes on to point out that most of these military type ID ntnbers don’t Can anything to a person without a substitution list, Maybe this will help someone to keep rom passing up otherwise new tubes at usually very reasonable prices, Most tiæs the seller doesn’t know what he has either, and wants to be rid of the tubes

KAY, OKAY, I’ve dragged my feet ’til now, but the nostalgia bug has reared its ugly head once ore, And now, another episode of EET TEE TUBE. Many years ago I was trying to decide between taking woodshop or electronics in my freshman year in high school. Since I knew absolutely thing about either, I sent to the library to look these subjects up, While going through the tacks I came upon a book that simply said on its binding “TUBES It was a period RCA tube substitution manual. I took it down from the shelf and leafed through trying to make sense of t all. Here was a book with pictures for better understanding which I couldn’t understand, ow, this is something, I thought. Then my eyes fell upon the words : “PENIAGRID CONVERTER.” that moment on, woodshop was out of the picture, as I began to imaging hanging around

Kennedy in a white shirt and narrow tie casually dropping phrases like PENTAGRID CONVERTER nto the conversation. Anyway, with a tear in the corner of my eye I give you the 12BA7 entagrid converter. It’s the very tube that started me suffering through eight semes ters with “Blinky’t Austel, who kept trying to teach me about these things called transistors

The 12BA7 is a miniature-type tube used as a converter in AC/DC superheterodyne circuits , especially those for the FM broadcast band, Heater voltage is 12.6 V AC/DC at O, 15 amperes. Except for the heater rating this tube is identical to the 6BA7, No substitutions available

Modern electronics forces us to talk in abbreviations We have ICs, QfOS, and such, Wonderful gadgets that can be destroyed by the static electricity in your fingertips. But what young ham can forget firing up his first one-tube transmitter and goofing up the plate setting, making the tube glow cherry-red? It never complained, It unders tood you were new at this thing called electronics , It forgave you and let you try again, and in trying, learn, Remember your mother yelling •down the basement stairs with the lights 1 in the house dimed? Nope, you just can’t pull that one off with an IC circuit,

Before the nostalgia bug leaves me completely I must relate an experience at a recent 1 was walking around with a friend who is a rather jaded Extra-Class ham with all the awards, a 2 kW station, and no more worlds to conquer, We came upon one table of goodies and he broke into tears, There on the table was an two-tube transmitter, He paid the $5,00 asking price a cardinal sin In hamfest circles, As we headed on he related that he

started off with one of these little crystal-controlled transmitters, and he never recaptured 1 the spirit of those tiæs no matter how hard he tried and how many awards he accunulated, Well, he took this thing home, fired it up, and the last I heard of him he was floating around the novice bands having the time of his life once again.

A few Is•sues back we related that Ken Vito Zichi was willing to share his SAS/RDERS collection with members for a SSE and $1, His address has changed: 2017 Dexter Road, Ann Arbor, MI 48103 will now find him. SUE COULTER, Space lla, 1000 West Colunbus Av., Bakersfield, CA

93301 also can be contacted for schematics for older radios, Between the two of these HSNers I’ll bet you can find whatever your little heart desires,

PSSST.. EX , BUDDY. , .Ya say you aren’t an uateur radio operator yet??? Well, wake up and smell the 12AX7 burning, bunky! Now that the volunteer examiners program is in full swing it is easier than ever to get licensed, No more trudging off to FCC offices, Any local group of hams or ham club in your area will have VECs willing to you into hamdom, Why, even your publisher might become a ham! (That’s a hint, Chris, ed) (I’ll wait for the codeless licens even if I have eo have the application buried with me, ch), Don’t any hams? Well, contact the 225 Main Street, Newington, CT 06111. They will get you in touch with your 1 nearest VEC group. The reason I pushing amateur radio even to those who have long resisted the urge Is that the bands are full of old Uncle Charlies who go all the way back to the days of spark gap transmission, and some of these old birds (said affectionately in case any of you are old birds) know so much about tube-type technology that it would be f0&1ish for a serious HollowStater not to tap into this data base. (I think the old birds will get more upset at being referred to as a ‘data base’ than they will at being referred to as ^told birds, ^thi! ch) Did you know you could raise bias voltage of a power supply that teeny extra tad you need by hooking up a 9-volt battery In line with it? No??? Well, get on the air with these folks and you will learn all kinds of tricks that never appeared in any technical manual or magazine,

WHILE ON SUBJECT OF RADIO, those of you who are interested might drop me a card telling me what bands you are on so that we might give consideration to a regularly scheduled net, I could only be net control about once a month, but we might rotate that responsibilit We could publish the schedule in these pages so that (you mean us peons, Skip? hi! c could listen in and benefit from what we have to offer.

MATT STUTTER}EIM, 510 Main Street, #732, Roosevelt Island, 10044 lists the following quipmene for sale :

licrafters SX-62-A receiver, .54-108 continuous Works, but needs lignment

C GPR-90 receiver with GSB-ISSB adapter, Both in near mine condition , except that receiver only works on two lower bands . . 200.00 Hamarlund HQ180A receiver, good condition. 225.00 01 lins 51-J-3 (R-388) receiver. Coast Guard issue, 185.00 -1134/WRR-3 receiver, Covers VLF 15-600 kHz, No power cord , as received.

Uses digital readout like R390; appears to be ok, never used by me. 125.00 Hamarlund SP-600, , 54-54 receiver. 175.00 ycom R-2174-A VLF receiver, 10 kHz to 450 kHz, in portable case. Has large signal strength meter/ panel speaker• 95.00

Coumraunitronics >R-17 receiver, 25-225 >Nz, AM-CW-FM, with LED readout, thumbwhee 1 entry of frequency, plus fully functional spectrum analyzer/ display, Ins truction manual (cost $150 in 1984) included. Solid state (boo! hi! 500,00

Surplus rack mount (19″) RF distribution amplifier. Plug In an antenna and it ill distribute identical signals to eight receivers, Hollow state. Covers 2-30 z, With panel tube-tes ter/meter 65.00 receiving antenna tuner 45.00

J-1020 active antenna 55.00

out Interfering stations, use for DF

HC-IO, extra IF states plus audio up, Takes 455 kc from receiver and reconverts to. 60 kHz IF strip with passband tuning, notch filters, SSB detection etc, No cabinet but complete

95.00

Kay-Dymek DA-5 BC loop with up lifier. Sleek looking, Good condition. Nulls

Heath SB-620 Panadapter/Spectrum display , 100.00 su FRA-7700 active antenna with AC adapter 50.00 -752 active audio filter65,00 Racal RA-17-C-3 receiver, 500 kHz to 30 rack mount, works well, good hape, but could use a realigrment for even better performance , 275,00 entrol 160 meter longwire antenna tuner (transmitting) . 100.00

C loop built by Bohac, excellent , 160.00

11 prices are exclusive of UPS shipping, Matt’s phone number (212) 838-5182, no collect alls, please,

OUR STOCK OF ATICLES is quickly returning to healthy proportions , However , I must ask you 11 to go to the well again and continue to produce stuff, The reason is that your umble editor has taken on a responsibility to Uncle Sam by joining the Amy reserve

Gerhaps another way to get R390s ? ) , I will be heading out for training at Fort Benning onetime this June, so the steer issue will need to be prepared not too long after the pring issue has gone to press, so remember: they also serve who only stay and wait! ! !

et your articles in early, You ’11 be doing your news letter and your country a big favor,

Come to think of it, you’ll be doing me a favor too there’s no place to plug the electric

UBLISÆR ‘S CORNER. Well, your publisher learned his lesson as regards DX furniture recently, or the last four years my R390A and my HQ150 or whatever other receiver I owned stood on a kitchen table in my bedroom, I had no occasion to move it, so it just stood there, Well, I ecently added a roomate with bed to my menagerie, and had to move the radios to the ther wall to accomodate her, Well, we got the radio table over there, all right, However, adjusting the position to accomodate the window repairman, the rear left leg fell off and the equipment fell (or, rather, slithered, as I had the presence of mind to hold things as well as I could) to the floor. The table, being made of particleboard, was not really turdy enough to hold all that heavy equipment. I bought some bolts and drilled holes through the tabletop to bolt the leg back on, The R390 hides the boltheads nicely, and the left ear leg will now stand even after the rest of the table disintegrates I have more bolts for the right rear leg. The moral of the story is: when you own heavy hollow state equipment,

make sure your furniture will be sturdy enough to hold it,

Meanwhile, as usual, we leave the December/January issue of HSN until the holidays are well over. Well, we ’11 call it the winter issue from now on, I haven’t gotten any complaints yet, but this is in case you wondered where the December issue is,

Skip and I don’t contemplate any increase in the Domestic/Canada/Mexico rate when postage goes up by in February,

You will notice an advertiseænt for Sue Coulter and Stan lopes is included in this issue. This is an experiment to see whether an occasional paid ad will keep the costs down, We aren’t making any money on this one, as the ad rate only pays for printing the ad itself and part of the postage, We aren’t beating the bushes for comercial advertising, but if any of you out there have a Hollow (or even, fie, a Solid) State-connected business and you wish to run an ad, write your publisher for details,

1 1 1

THE HOLLOW STATE c/o CHRIS HA>SEN, P.o. BOX 1226, YOR.K, NY 10159.

EDImR: SKIP AREY, P.O. BOX 421, NJ 08060

PUBLEHER: ushSEN, P.o. BOX 1226, ‘ORR, 10159

Please send all subscription orders, inquiries, and address changes to Chris Hansen; send all editorial material to Skip Arey.

All articles and information shared through this newsletter may be reprinted only with permission of the author. The publishing co—ittee asstmes no responsibility for the accuracy or safety of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned or advertised in the Hollow State Newsletter, The Hollow State News letter is available at the price of $4 for one year, or $8 for two years, Frequency of publication Is quarterly: Winter, March, June, September, Back issues 5-8 are available from the publishe at $1 per issue, Saples are available at the price (the most recent issue will be sent) Inquiry sheets are available for a SASE, The above prices are for US/Canada/.Mexico Residents of other countries should double each price: $8 for one year, $16 for two, back issues $2, samples $2 or 4 Inquiry sheets available for 4

THE NEXT PUBLISHING DATE rs WRCH. YOUR CONTRIBUTIOIS OF W.TERIAL MAKE THIS >EWSLETTER POSS .

SUBSCRIBERS NOTE: Check your mailing label — if corrections are needed send corrected label to the publisher at the New York address above. To find out when you are due for ænewal, look at the envelope. If the legend ‘last issue please renew ^tappears, this is your last issue, Otherwise, look at your label you will see the words ^tSUB EXP and a nt.mber, The nt.mber is the issue number of your last issue (9 is March 1985, 10 is June 1985, 11 is September 1985, etc.) Thank you for your support.

WANEED TO BUY: Automobile radios, BCB only models and/or European models with LW/MW/SW,

Unfortunately, no tube radios needed (too much bother to hook up and keep going) , Also looking for a rack/ stand suitable for R-390A and SSB converter. Write your publisher, Chris Hansen, P .0, Box 1226, New York, NY 10159 or call (212) 549-3039 (no collects),

æHOLLOW

NEWSLETTER

ADDRESS FOR SUBSCRIPTIONS: Chris Hansen; P.o. Box 1226; New York, NY 10159

EDITORIAL ADDRESS : Skip Arey; P.o. Box 421; Mount Holly, NJ 08060

SUBSCRIPTION PRICES : Domestic and Canada /Mexico. • $4 for four issues

$8 for eight issues Make checks pay- Other foreign: $8 for four issues, $16 for eight issues able to: Back issues : $1 each USA/Canada/Mexico, $2 each other foreign; CHRIS HÆSEN

UBLISHER’S NOTES — I ^tm going first this time around (sorry, Skip) to emphasize some new developments. First, we are going to go on a schedule of four times a year WHEN THE MATERIAL NTS . Very important, that phrase. It means that you are now our partners in produc ing low State News letter. Send your material original articles on any subject bearing upon tube-type receiving equipment (care and feeding, or usage, or even nostalgia articles are agerly solicited). I am retitling the month of issue to reflect the season spring, ummer, fall, winter of each year, Your subscription will still cover four issues it might cover more than a year, depending upon your response to the above appeal. So, get those quill pens and word processors and your a—s in gear! ! We await stuffed post office oxes .

AVAILABILITY OF BACK ISSUES Now that my office is providing free copying, I am reprinting the first four issues of HSN (then called R-390 Newsletter). To celebrate my employers’ (yes, that apostrophe is correct there are three partners) new bounty, the first four issues of

N are available as a package for $3.50. Single issues are available at the customary $1.00 a piece. As always, issues 5 through 8 are available at $1.00 a piece. Send your orders to Chris Hansen at the above address, enclosing a check payable to “Chris Hansen”. (HSN is still too small an operation to have its own account) .

EDINR’S NOTES GREETÜ•JGS CANERS ! Welcome once again to the best little newsletter in radiodom. Tlings have been happening at your humble editor’s shack. After spending many onths -trying to find a tube-type computer (ENIAC is still mostly in pieces at the Smithsonian and the Franklin Institute has no idea what happened to their UNIVAC; besides, my basement is too small), I now have a Commodore SX-64. Eventually, I will acquire a printer, and we should then be processing away just as our esteemed and revered publisher (okay, Skip, how much do you want? hi! ch), Anyhoo, your editor would appreciate any programs or data which might help him In his awesome tasks let him know.

(YOU MIGHT CALL IT BEGGING) The material for publication has been coming me at a steady trickle however, it is still just a trickle. This creates a problem for ady publication dates. As Chris has mentioned above, publishing dates are now going to be flexible darn the dates, just publish when there is a sufficiency of material. We would rather please you by putting out 3 issues a year of great relevance and utility rather than putting out 4 with 6 pages of filler per year (one full issue), As Chris mentioned above, subscriptions will still be for four issues however, those four issues may or may not constitute one year. In fact, if we get five issues worth a year, you might find a special issue published! ! Of course, we do seek your and opinions on this matter If anyone is unhappy with HSN for any reason, refunds are cheerfully provided for all urnailed issues (which is more than many connercial magazines will do ! ) , So, get to your desks and write ! ! !

POWER LINE SURGE PROTECTOR Our first bit of information comes from the ever-present DN,IÆ LANKFORD. He writes: ‘ ‘One usually thinks of power line surges and spikes as being dangerous only for solid-state equipment. But, these glitches can also destroy capacitors with ratings 1 of hundreds of volts (like those in our tube gear) So, Dallas has invested in a Radio

Shack ‘ ‘transient voltage surge protector,” which is a three-prong plug-in device which accepts in turn a two- or three-prong plug. It is rated at 15 Üps. It may seem expensive at $7.50, but even if you repair your own gear, your time is worth something; it does take time to find a single blown capacitor in an HQ180, R390, or similar gear. Anyvay, it seemed like a good buy to Dallas, More from Dallas later.

ANTIQUE R.ADIO CLASS IFIED Every now and then a useful publication comes across your

editor’s desk. There is another resource for tube-type folks in the Antique Radio Classified, 9951 Sunrise Blvd, #R9, Cleveland, OH 44133. You can obtain a sample issue for $1.50, or subscribe for a year (12 issues) for $15.00. The magazine contains some pictorial articles of ^r20 ‘s and ’30 ‘s-type gear, and lots of classified ads for many different old rigs, parts, tubes, and the like. It seems that it might apply mostly to the needs of our friends who go for truly antique radios, but then one can never have too many tube sources, can one???

MORE TUBE SOURCES Speaking of tube sources, here are a few more to warm your hearts :

Steinmetz Electronics, 317 Pulaski Road, Calumet City, IL 60409 and Old Tyme Radio Company, 2445 Lyttinsville Road, Silver Spring, I’D 20910.

TELL US ABOUT YOUR EXPERIEhCES WITH SUPPLIERS Your editor and publisher have been passin along names and addresses of tube sources since the first R390 News letter. However, we are panting like hinds for some news of your satisfaction (or lack of satisfaction) with any tube sources you deal with. Found a friend with a tube source? Do you know a really upright and hones t — exceptionally upright — tube source? Share your experiences. Have you been bu by a tube source? Did the Dud Tube Source Emporiud live up to its name (hi ! ) ? frten, help your fellow tube enthus lasts by passing the Information along. If you have doctmentation , it might help to send copies eo us. Telling the company that you’re going to expose them in a tube enthusiasts’ newsletter might help to gain satisfaction, In a future issue, we will draw together all the tube sources into one comprehensive list, Perhaps, with a little prodding, we’ll try to get some more comprehensive Information about their services and resources . Help us out with reactions to ‘Duds ^tand ‘Goods

MAMJAL WANTED FOR RI^ME-84 RECEIVER. Member IORRIS SORENSEN, 111 Town Line, Milton, ON, CANADA L9T 2XI recently purchased an old R>E-84 receiver, manufactured by Radio Manufactures Engineering of Peoria, IL, ca. 1946. It is in good working order except for the non-functioning o the BYO. This rig uses Loktal (lock-in type) tubes and has a mechanical bandspread which seems capable of providing fairly precise tuning. Morris would like to obtain a manual for this receiver, and would also like to hear from any readers who may have used one,

A SOURCE OF INFORMATION ON HQ129X AND Hq150 receivers is the National Radio Club Receiver

Manual, Vol. I. For a catalogue listing this and other NRC publications, you may write to Publications Center, P.o. Box 166, Mannsvflle, NY 13661.

WANTS INFO ON BC-221 FREQUENCY PETER 4131 South Andes way, Aurora, CO 80013 has recently acquired this piece of equipment. He would like to correspond with anyone who has a manual or information about the meter. He would also like to correspond with users of 1 older RBB receivers (he has a manual available for copying). Lis ten for Wayne ^qs ‘Medium Wave Interlude” program on DX-Party Line on HCJB, Quito, Ecuador. The times QIT are: Saturday 2130, and Sunday 0230, 0630, and 0930. We like it! ! See recent WRTH or program schedules for frequencies .

ROTHER SOURCE FOR ARRL HANDBOOKS AND TUBE SUBSTITUTION MANUAIS could be your local librar Some of these might be available for sale as well as loan (many have already been sold. ch) , You might even be able to trade a copy of this year’s Handbook for a 1960 or so! !

ELECTRON-EYE TUNING TIDES EELAINED sue Coulter provides us with this tidbit of information from the February 1983 issue of a service magazine concerning these tubes. Known as the ‘*Iaco Tuning Indicator”, this self-contained unit makes use of the 6E5 electron-eye tube and ob- tains its power from the radio set itself through a five-wire cable connecting with various rcuits. The installation is simply cutting a hole in the set panel for the neat bezel ring r the through which the tube target is viewed, and mounting the bracket behind e panel, For precise tuning the set operator views the electron-eye target of the 6E5 tube through the bezel window. When the set is sharply tuned for a given signal, the black segment of the luminous green circle is reduced to minimum width, if not entirely eliminated, This closed eye condition indicated maximum resonance, mie Taco Tuning Indicator was manufactured by Technical Appliance Corporation, 17 East 16th St., New York, NY (Hey, Chris, take the bus into the city and k•rock on the door, they might still be home! hi!) (I doubt it. However, I once owned an Scott radio which made use of two of these tuning eyes, one for EM. and one for Æ(/SW. The Af/SW one could never be induced to work, but the one was a beauty, and I still think that it was the best tuning aid around better than a meter as It didn ‘t fluctuate so wildly. ch)

>EET TEE 6E5 TUBE That beautiful blue glow (mine was green, ch), those perfectly-emitted photons, the precision the total class it brought to a radio. I ‘vp seen these things in use on a receiver well into the ’60’s In some cases they were applied to substantially solid state units. This can mean only one thing: let’s >EET the 6E5 TUBE ! ! !

The 6E5 is a glass-type electron-ray tube used to indicate visually, by means of a fluorescent target, the effects of a charge in a controlling voltage. It is used as a convenient means of indicating accurate receiver tuning This tube requires a six-contact socket. Its heater voltage is 603 volts AC/DC at 0.3 amperes,

Plate supply voltage 250 V max,

Target voltage 250V max, -125V min,

Plate and Target supply voltage 200v/250V ries triode plate resistor 1 megohm arget current3-4 ma

Triode-Plate current0.19-0.24 ma

Triode -Grid Voltage (apgroxiute) : 6E5

for shadow angle of O . -6.5 to -8.0 V for shadow angle of 90⁰hOTE•. Target current and Triode-Plate current are subject to wide variations ,

CATAIDGIJE: &10ther catalogue has crossed your editor’s desk, This one includes a good collec tion of tubes and other radio supplies, including trans formers and chokes. mqTIQI.E ELECTRONICS SUPPLY, 1725 W. University, Suite 2, Tempe, AZ 85281 (602) 894-9503. Also, especially if you are looking for surplus Collins gear parts, inc luding mechanical filters , contact SURPLUS SALES OF hEGR.ASK.A, 2412 Chandler Road, Bellevue, NE 68005. These folks have a lot of neat stuff, espeially some surplus stuff off missiles and aircraft, so if you want to build a delivery system to launch your R390 into space, this is the catalogue for you.

AI•OTER CATALOGUE: Jay Mathisrud us of another catalogue you might be interested in, RADIOKIT, P Box 411, Greenville, NH 03048. Price: 50C, Tleir book includes many fine new components of use to the builder,. repairer, and res torero There are air core capacitors to be.found here (hen’s teeth are more prevalent these days). They also feature a kit to convert the DRAKE R4A, R4B, & R4C to continuous general coverage, Pretty neat, huh?

ANTIQUE RADIOS RESTORATION AND PRICE GUIDE, Johnson, David & Betty. Your publisher received a copy of this book recently (it was published at $10.95 but sells for much less from Publisher ^ts Clearing House). In case there are some HSNers who are also interested in antique radios of the type prevalent from the 20’s to the ‘ 50’s, I ^f11 review the book at short,

At 99 pages, this book can’t go into much detail about restoration (in fact, they spend as ch time talking about cabinet restoration as about the actual radio res toration), To heir credit, however, they realize that anyone who is much interested in these receivers will hunger for more infomation, so they have included a generous bibliography, a list of

sources for parts, especially ‘IUBES , (Most of them have already appeared in these pages . ) The best part for the non-technical person like myself is the chapter on radio theory. The pics and the price list are good for laughs and memories too If you come across it somewhere and have some $$$ burning holes in your pockets, you could do worse than to pick up a copy. Who knows, someday an Atwater Kent may land in your shack !

REPAIRING R390A AGC GERALD MURPHY has this to share with us concerning the AGC time constant on the R390Ao ‘ ‘After about 15 minutes Of warm-up, the receiver gradually lost all AGC in the slow setting and partially in the medium setting. Checking with my VOM, I found that C551, an electrolytic cap in a metal can sheidl on the IF sub- v esos chassis was defective, measuring only about 250KpermcN ohms resistance and passing DC current. In repair- g.22!2ÉD NOvww

13 of

ing this defect, I purchased a 2 ufd non-electrolytic cap (GE 457A373H01-400 VDC original was 500 VDC).

In order to preserve the ‘ambiance’ of the R390A, I CS5/ (2 afd, pulled off the contacts of the original capacitor, drained off the fluid, desoldered the can, and, after

(vsuA ) carefully insulating the new capacitor leads and lining the can with heavy cardboard, placed the new cap In the can and sealed it with silicone cement. Perfect fit! It is necessary to solder wire extensions onto the cap leads, and these were taped to the body of the cap with good plastic tape. In making this repair, I also replaced C548 with a new 400-VDC Mylar-type unit. It is phys ica 11 y in the way and is rated at 100 VDC. In order to insure good mechanical rigidity, it seemed wise to mount a terminal strip on the chassis partition where C504 and C505 are gounded A diagram is above,

DALLAS LANKFORD ON HQ180A. It was interes ting to note Edward McFadden’s remarks about R-18 (47 K, 2W) in his HQ-180A which had burned up and caused the 10K section of the dual

10k’/ 5K RF gain pot to also self-destruct. Chris Hansen sugges ted parenthetically that bad 6BZ6’s might be the cause, as they appeared to be from Edwarcrs conunents, Another potentia cause is that R-18 dissipates about We Because of its crowded location, it may actually be operated beyond its power rating, Apparently Edward’s HQ180A is a late model because earlier models used R-106 (100K, 1/2 W) in parallel with R-18 (100K, IW) to achieve 50K o I described this situation in a Musing in DX News, v .51, #21 (March 5, 1984), and suggested essentially the same so lution that Edward described g Actually, I used two 100K, 2W as the equivalent of a 50K, 4W, and mounted the resistors on a terminal lug strip which was mounted on the L-bracket that supports the bandwidth and sideband switches. Removal of R-18 (and R 106 if also present) is non-trivial, and I recommend using small pieces of scrap aluminum as heat sinks -shields to protect nearly wires and components from the hot tip of your soldering iron. One other resistor in some older HQ180A’s and HQ180’s was underrated: R-3 (608 K, 1/2W) should be increased to IWO When changing the R-18 (/R-106), you should be especially careful when re-doing the tie points from which the resistor(s) was (were) removed and to which th associated wiring connected 0 In one of my units about a year later I noticed that my S-meter was making small but noticiable random discontinuous jumps. Ihe problem was traced to my R-18/R-106 mod 0 ‘mie original feed to R-18/R-106 was a red wire that ran from a terminal lug on one of the IF transformers. This lug was also the tie point for two other red wires (the B+ line). When I originally did the mod I did not notice that one of the red wires was not finnly crimped to the lug, but merely ‘stuck througho’ So, when I resoldered, the solder joint not good, causing small variations in the B+ supply to some of the IF tubes , which in turn caused the small random discontinuous S -meter jumps . The lesson here, I think, is that when you disconnect one wire from a lug, check that the others are firmly crimped to the lug , I had carelessly assumed that Harmnarlund never use& bad wiring practices, but learn that they did, the hard way.

Another thing mentioned in my DX News musing was that many (most?) HQ180A’s (HQ180’s?) have B+ voltages that are too high. The nominal B+ line per manual is 255 VDC, but both my 180A ^ts ran around 290 VDCO This can cause a number of components to be operated beyond their maximum ratings , and may also have been a contributing cause of the problems that Edward observed, The audio output tube definitely operated beyond its maximum ings , which can lead to frequent tube failures, and cause associated component failures . The solution is to add a dropping resistor in •the B+ line. The exact resis tance seems to vary from one HQ180A to another, but 125 to 140 ohms is about right from my experience . In my units I currently use a 100 ohm 50 W in series in series with a 25 ohm (or 40 ohm) 25W, The equivalent 125 ohm (or 140 ohm) resistor is inserted between the output of the silicone diodes and the 8 henry (L-6) filter choke, For improved ventilation the two resistors are mounted vertically above the chassis near the rear behind the main tuning capacitor and between the power transformer and 100 kHz crystal oscillator tube. A couple of holes were drilled through the chassis to mount the resistors and to feed wires through, It seems that I also a terminal lug underneath, The high wattage was necessary to get the resistors to run reasonably cool (about 55 ⁰c) e A sketch of the mounting arrangement is above,

HAMFEST SEASON Remember to make up a list of all the tubes in your receivers and upport gear, Also , take a look at a few tube catalogues to get an idea of premium prices

If you purchase a boxed tube Æ.,WAYS look inside to make sure the right tube is in the boxe

Some of the sellers at buy these things up in bulk and even they don! t know what ey have, Also, if you see any rigs being sold as is’ or as scrap for real low prices , e a look inside and see if they contain any tubes or components that would make It worth dragging the rusty hulk back to your car If you are in the market for permeability-tuned adios like the R390 ALWAYS ask to look inside and really pay attention to the condition of the planetary gears and the slug racks. Try to get an idea of the quality of the radio by listening to the seller talking to other people, Does the seller sound like an old-timer with respect for this gear, or does he sound like someone just trying to unload a boat chor that he got when he was a novice and never got to work right? Remember, knowledge is power If you ‘ve been reading the HollowState Newsletter you’re equipped to make intelligent purchases , CAVIAT EIQTOR. COGITO ERGO SIN. ILIEGITn,f1 NON CARBORUNDLMO

PUBLISHER’S CORNER (as opposed to “Publisher’s Notes” on the front page, hi!) . I a new (re)subscriber to Glenn Hauser’s Review of International Broadcasting (Box 490756, Ft. Lauderdale, FL 33349 $18/ yr US , $21/ Canada,samples $1.50), Since I last saw this publication, a new department has emerged, called ‘ ‘Radio Equipment Forum,” edited by David Newkirk, Mr. Newkirk, who is sometimes quite witty and pointed, has an interchange with a gentleman named Steve Kennedy this month, partially about tube receivers, Mr. Kennedy: ‘1 1 can’t overstate the usefulness of having a decent-quality older tube receiver on hand, There is a special feeling about working with one of the old sets …a special feeling of working with a radio that was built with a serious SWL/DXer in mind, , . a charisma, if you please, The audio in the old sets is not bad, either.. , sure, it’s a 6BQ5 or a 6L6, but it sure can make BBC or Radio Nederland sound solid when hooked to a good speaker, But be warned! Once you have tried a ‘hollow state’ receiver, . , you might get hooked ! ‘t (I think HSN has added something to the language, ch) Mr. Newkirk: “I think we should point out another distinction (between newer receivers and older tube receivers): there is a great difference between sets made for

‘ ‘real” use and sets whipped up for “consumer” use in any era, The difference in quality tween any Hallicrafters or National receiver and (the) R390A is as tounding, The R390A ifts little and has linear digital-readout tuning if properly aligned. Its weak point, as was the weak point of many receivers . is that it doesn’t do well at all in the most comwn SSB/CW listening technique these days, RF/IF full up, and agc controlling receiver gain. This is because of: unoptimized detector (just the rectification detector (“&1”) diode used with BFO added), BFO too weak by the time SSC/CW gets to the end of the IF strip if the RF/IF gain is up all the way, and inadequate ÆC control range. , . Really, you see, there IS SUCH THING as “state of the art It’s a science, not an art, and the fact is that if you just understood what was said on your radio in other words, if the message wa unders tood — then your radio is as “state of the art” (CHOKE) as it need be, Fact is , ^t‘state of the art” is a cliche invented by and is a carrot ‘tied to the stick that radio amateurs and broadcast station engineers tie to their own backs along with the carrot eo keep themselves busy and make thuselves feel that they are achieving “progress .

Well…I must say that Mr. Newkirk’s distinction between ‘connercial’ and ‘real’ receivers is new to me I like it, It explains somewhat the mystique around the R390, R390A, HQ180, HQ150, and the like. These are working receivers. People used them, not for hobby listening, but to earn their bread. Soæ of the aura of their efforts has stuck to our receivers, and it can help turn a hobby into an avocation and a serious pursuit of excellence. THE HOLLOW STATE NEWSLETTER, c/o HÆSEN, P.o. BOX 1226, NEW YORK, NY 10159

EDITOR: SKIP AREY, P.o. BOX 421, NJ 08060

PUBLISHER: CHRIS P.o. BOX 1226, I’ORK, NY 10159

Please send all subscription orders, inquiries, and address changes to Chris Hansen; send all editorial material to Skip Arey.

All articles and information shared through this newsletter may be reprinted only with permission of the author. The publishing connittee assumes no respons ibility for the accuracy or safety of untested modifications of equipment or the reliability of suppliers of services , parts, or equipment mentioned or advertised in the Hollow State News letter. The Hollow State Newsletter is available at the price of $4 for 4 issues, or $8 for 8 issues. Frequency of publication is roughly quarterly, Spring, St.tmer, Autumn, Winter (approximately months of March/April, June/July, August/September, December/January). Back issues 5-8 are available from the publisher at $1 per iésue. Back issues 1-4 are available as a group for $3.50, or singl for $1 apiece. Samples are available for the same price (the recent issue will be sent The above prices are for US/Canada/Mexico, Residents of other countries should souble each

price: $8 for one year, $16 for two, back issues $2, back issues 1-4 as a group $7, samples $2 or 4 IRC’s.

THE NEXT PUBLISHING DATE IS JUNE/JULY, BUT THIS DEPENDS ON YOU! ! ! GET YOUR MATERIAL ’10 SKIP

AS SOON AS POSSIBIE, FOR YOUR THIS EEWSLETTER POSSIBLE

SUBSCRIBERS Check your mailing label — if corrections are needed send the corrected label to the publisher at the New York address above, To find out when you are due for renewal, look at your envelope 0 If the stamped legend ^tLast Issue Please Renew’ appears in red, this is your last issue. Otherwise, look at your label: you will see the words “SUB EXP 4k” and a number. The number is the issue number of your last -issue, ‘mank you for your support,

1 1 1

NEWSLETTER

ADDRESS FOR SUBSCRIPTIONS : Chris Hansen, P.o. Box 1226, New York, NY 10159 DITORIAL ADDRESS: Skip Arey, P.o. Box 45, Beverly, NJ 08010 (NOTE CHANGE! ! ! ! )

rice: ‘ $4 for 1 year/ four issues, $8 for two years/8 issues; back issues (all currently available) $1 apiece. Double all prices for subs outs {de US/Canada/Mexicoe

well, well. . .here we are at the nether world pass between hollow and solid state. Living orever two major technological jtnps behind the rest of the pack, where portable means nything less than 35 pounds. Yes, friends, the twilight in the Twilight Zone is the glow of 61,6 ⁸3 , 3TF7 ^ts, 35W4’so As we sit warmed by this glow, let us begin.

NRIAL CHANGE I>MNENT HSNers may or may not know that I have taken on new responsibilis (including the Army Reserve and a new house). Chris and I went on a search for one new editor, and came up with three. will be more details in the next issue, but suffice t to say that Skip will continue as a Contributing Editor, and two other HSNers will do the ditorial Honors! All Chris will be doing is getting this thing printed and mailed, and depositing your checks (hi ! ) . In any case, contributions are solicited to kick off the new Editorial Department with a bang you should send them to Skip’s NEW address above. kip will collect them and forward them to our new editor, whose computer word-processes so ell that HSN is likely to win a design award (hi!) .

arage sales for ooks??? WHY NOT?

LEA MARKET SEASON — Do you have your list of needed tubes made up? Are you scouring the old five-tube radios??? Are you attacking hæfests In search of tube data Make hay while the sun shines, folks, so that the winters of your days will continue to be warmed by Hollow State. (In the st.æer you’ll need air conditioning, hough. It’s 90 here In the Bronx today. No tine for tube heat! ch)

EGULATOR SUBSTITUTE Our first contribution this month comes from Gerald W. Marphy,

hlrphy writes: ‘ When the RT-510 tube in my R390A failed, I devised a simple interim ubstitute while trying to track down a new tube. I used the 12.6 volt heater section of a 2BH7A 9-pin miniature tube connected in series with the heaters of the BFO and PTO tubes ,

In the series connection this tube’s heater draws 0.3 amp, which is just what is needed, The ppropriate pins of the tube were connected together as noted In the diagram (next page) so he tube can be plugged right into the regulator socket. The shunting wires were soldered into place after scraping each pin to get good contact. I used a heat sink in the fom of a emostat to protect the tube. This set-up works well and could be used permanently. I could etect no adverse effect on stability after warm-up. There may be a bit of regulating acn, In fact, since variations in current would prestmably cause some temperature-dependent

Cts on resistance and current in the three heaters . I think this is a better way to go an to replace the two oscillators with 12.6 volt heater tubes; that route may result in a eed to do some realigning of the PTO to get accurate calibration and linearity. ” SEE DIAGRA{ PAGE 2)

SU€STI

Also, Dro M.rphy needs a copy of the (TM-11-5820-10) R390A Manual, He will pay

costs and copying. Contact

him at Box 152, Scottsville, (Ed

NY 145460

BALLAST TUBE REPLACEMENT KIT

AND SSB ADAPTOR NOT RECOn,ENDED 8h2e

BY DALLAS LAM<FORD souD For your consideration, the fol— (s was) lowing wit and wisdom of our own COPER DALLAS LANKFORD. In this writing Dallas refers to a modifica-

SOLDERED tion published in our first issue. Dallas writes : PINS

⁸‘Because of the increases in

3TF7 prices, I decided to look Into the solid-state ballast tube replacement advertised by G

Comunications in Hæ Trader Yellow Sheets and elsewhere. I also purchased their R390A SSB adaotor at the same time. What a waste of money! The ballast tube adaptor is and looked homebrewed. The adaptor base had been carelessly ground away. It was such poor workmanship that I didn’t even bother trying it out 0 Worse yet, I could not have used it anyway, because parts of the adaptor mount on the outer side of the R390A in such a way that there is not enough clearance to re-install my R390A’s in their cabinets, The unit comes with one page of installation and operating instructions, and no schematic. The unit is not completely ass bled, and several solder connections must be made.

SSB adaptor also Is and looked hoæbrewedo It is a. small (1-3/4″ x 1-1/16″ x 1-5/16″) approximately rectangular piece of black plastic with four wires (two bare solid copper, and two #22 stranded insulated, one red, one black), coming out of the bottome The black plastic is some kind of homemade encapsulation. I would assume the circuit is encapsulated to prevent you from copying it. But, of course, this also prevents you from repairing the unit if anything goes wrong. The unit comes with one page of installation and operating instructions, and no schematic. The four wires are attached to terminals 3 (AGC), 10 & 13 (1 Ine output), and 16 (ground) on the rear of your R390(A). For operation the LIIE PETER switch is set to +10, and the LINE GAIN is set at 7-8. The unit I received did not operate as described in the operating instructions. Also, with the unit Ins talled, local audio gain was greatly reduced, and audio hiss obscured weak SSB signals I do not know if you can use the line audio while the SSB adaptor is attached. However, this is perhaps a moot question, since I would strongly against purchase of this SSB adaptor. The SSB mod described in #1 of the ‘*R390A Users Group” (HSN’s predecessor) is vastly superior, and requires only two diodes, a resistor, a little solder wick, a. little solder, and a little of your timeo 1 I am enclosing a diagram of that mod for reader information, ” (SEE PAGE 3)

LOCAL COWR FROM SKIP I think the very first time I ever tried my hand at anything electronic was when my five—tube beds ide radio stopped ”radio-ing” when I was in fourth grade. Like any bright young child I proceeded to take the back off, (Aren’t you glad they had cord interlocks even back then?) , thereby for the first time ignoring that most ignored little sticker USER SERVICEABLE PARTS IISDE! ‘t “Ah ha!” 1 said, ‘*Tubes 1!” There are five tubes in here and I bet at least one of them does not work, Well, I pulled the tubes right then (fortunately the tubes and chassis were well-marked because at that point I did not think to check that out) I took my five tubes and got on my bicycle and went to the local TV store to have them tested. The store owner helped me used the tube tester and even helped me detemine that the dead soldier was the 35W4e Ninety-eight cents later I was on my way home to perform my first repair. Two weeks later my grandfather gave me a transis tor portable. I opened the back, TIBES SIGH! Good thing I didn’t have to fix it. And so began a lifelong obsession which leads us into (drt..n roll please to page 4)

ßFFöRE :

AFTER :

R-3qoA 6SB/cw MOD ( BOTTom VIEW)

	Between pins 3 & 0.15A
NC	Between pins 3 & 6 o, 15A
35W4	This tube requires a miniature seven-pin socket and may be mounted in any direction, making it Ideal for portable and mobile use,

PEET THE TUBE Today, kiddies, we look at the venerable 35W49 This tube is a half-wave vacuum rectifier of the miniature type most found in the power supply sections of AC/DC receivers , It is equivalent in performance to the glass octal type 35Z5-GT An interes ting feature of this tube, and no doubt the reason it saw so much use in garden-variety kitchen table radios is that it provides a tap for the operation of a panel lamp or pilot light, See, that’s why the numbers glowed !

w/o pilot w/ pilot

Heater Voltage (AC/DC)

Entire heater (pins 3/4), 35V 32V section (pins 4/6), , 5.5V

Heater Current

Please keep in mind that I am not the only one capable of waxing nostalgic If you have an anecdote that might lead to a ‘Meet the Tube” please send it in and we will tell the world about the tube that had such a profound effect on you and this hobby, As contributing editor I will continue to supply our newsletter with ‘ Meet the Tube” as well as the occasional article, so continue to send ^tMeet the Tube” material to me at: POO 9 Box 45, Beverly, NJ 08010

Whatsamatter, Bunky? Ya say you ‘re looking for a Very Low Frequency converter? VLF listening is really taking off these days (your technical/contributing editor can’t figure out why, but live and let live. If you want to try your hand at the basement bands, a VLF converter can be iurchased for a reasonable price an advertiseænt• appears along with this issue for LF Engineering, Chris has purchased one and finds that it works quite well, considering the area In which he lives, More information on this facet of the radio listening hobby where neat old tube rigs seem to abound can be had by contacti.ng ‘ *rhe Longwave Club of America, 45 Wildflower Road, Levittown, PA 19057. You will find in their journal, ‘The Lowdown , ‘ t artic les by some of our own esteeæd users group members, From the few issues I have seen LOWFERS sea to be as creative at building and scrounging as all hollows taters are, Tell them HSN sent you,

CO>TUTER PROJECT FOR THE ADVENTUROUS 1 think 1 have come up with a project for one of our computer mavens, Could someone come up with a progru by which one could dtnp in all of their tube substitution data from all their tube sub books for quick and easy call-up? While such a program would have limited comercial possibilities it might be neat to provide to the public domain through the pages of HSN, A simple but adequate challenge to all you PC people, If you accept the challenge please try to write it in generic (microsoft) BASIC, COIQUTERS IN HSN??? There goes the neighborhood!!

IN THE “NATION’S ATTIC” Speaking of tube-type computing, if you get to the His tory %.zsetm section of the Smithsonian during your vacation travels this year you will be treated to a beautiful display of ENIAC/ UNIVAC class tube Rack after rack of Hollow State Heaven, Big octal tubes, too, not minis, We are talking leading-edge technology here, folkso Real back to basics stuff.

CHORES For most of us, sumrner is not DXing time. Vacations need to be taken, hildren need to be squired to and from camp, barbecues are waiting to be fired up, and ost of all DX is pretty poor overall, However, the hollows tater shouldn’t neglect his her) receiver during the sunmer,

st, try to fire the receiver up as often as you can bear the heat, in order to keep the ubes, capacitors, and such from deteriorating from lack of use.

Second, since vacations are rolling around, the DXer should open up his receiver , ust it Out top and bottom, and (if really ambitious), test the tubes and re-tube if ecessary, These new-fangled hand-held vacuums are great for the dus t-removal chores of the hollows tater they run for 10 to 15 minutes before needing a re-charge, and this is ust right for one receiver or two. Need it be said that some dust is FLAIOiABLE ??

hird, clean contacts with approved cleaners, check for bad connections, make sure any parts which must be greased (gear trains in the R390, for example) are sufficiently lubricated.

tennas may be checked in the surmner also we often neglect the antenns with results that could be disappointing during winter storms. Check that connections are not corroded, that all insulators and other hardware are in good condition, and that the connections to the receiver are properly lightning-protected.

I would add that sumer is the perfect time to buy more hollow-state equipment, but suspect that our various ‘ ‘War Departments ⁿmight not approve.

ther possibilities: if you live in an excessively humid area, you might have to check your equipnient for mildew or fungus Infestation! Best remedy for this: rejoin the rest of us in temperate climes (hi!) Insect infes tation is also not unknown (if you don’t fire it up enough to drive the critters out with the heat! A major cause of solid-state radio problems in some areas in NYC is that cockroaches take up residence and the radios don’t generate enough heat to drive them away! Those ^t‘music boxes” can become “roach motels ^{J J}!) I believe at a mildewcide is available in spray for^am perhaps someone who has had this problem give us more details (in the FALL issue, when it’s too early for next year and too late r this one, hi!) . If anyone has insects in their R390, fire it up for a few hours and most of them will either be fried or will leave,

IT’s A S}DRT ISSUE THIS IONTHO 1 hope that the membership will continue to support HSN by WRITING IN with articles and tidbits pertinent to Hollow State equipment, Send your material to Skip at the address on the front; he will forward it to our new Managing Editor, who will debut in the next issue, Thanks.

HOLLOW STATE NEWSLETTER, c/o Chris Hansen, P.o. Box 1226, New York, NY 10159

PUBLBHER: CHRIS HANSEN EDITOR: SKIP n-EY, P.o. Box 45, Beverly, ‘NJ 08010

All articles and information shared through this news letter may be reprinted only with permission of the author, The publishing connittee assumes no responsibility for the accuracy or safety of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned in the pages of t his news letter. The Hollow State Newsletter is available at the subscription price of $4 for 1 year, or $8 for 2 years 0 Back issues 1-9 are available from the publisher at $1 per issue 0 SatQ1es are available from the publisher at the same price. Double all above prices for subscriptions outside US/Canada/Mexico, An inquiry sheet is available for an SASE 0 1 would appreciate any publicity about HSN to mention prices and such for the greater convenience of the HSNer-to-beo

ERRATUM: In Dallas Lankford’s article on page 2, a sentence was mistyped, The sentence which now begins : “The adaptor base. . should read: “The adaptor base had been ground down during manufacture (if one can call it that), and some of several pins on the adaptor base had been care less ly ground away, Sorry, ch

410LLOW

^I>STATE LETTNEWS-ER

SUBSCRIPTIONS: $4 for one year (4 issues) , $B for two years (B i ssues) , back issues $1 each (all currently avai I able) , send check or money order payable to Chris Hansen (address bel ow) .

PUBLISHER: Chris Hansen, P.O. Box 1226, New York, NY 10159.

EDITOR: Dallas S. Lankford, P.O. Box 6145, Ruston, LA 71272-001B.

CONTRIBUTING EDITOR: Skip Arey, P.O. Box 45, Beverly, NJ OBOIO.

The opinions expressed in The HOI low State Newsletter belong to the ndividual contributors and do not necessarily reflect those 0+ the editors pubi i sher .

ED 1 • S CORNER

Dal las Lankford

Greetings from Ruston to all of our subscribers. As you can see, there have been a few notable changes. Skip is stepping down as editor and I have vol unteered to take over the editing work. This means that future contributions should be sent mainly to me. Skip is staying on as a contributing edi tor, and plans to continue with regular columns about tubes. So information which is relevant only to Skip •s col umn could be sent directly to him. Finally, we all owe Skip, the father of The Hollow State Newsl etter, a big vote of thanks.

Do you know something about al ignment, have a construction project, know suppl i ers• addresses for equipment, manuals or parts, want to buy or sell , have some useful modificati ons, or repair experi ences? Well then share your i nformation and experiences with everyone. Remember that HSN exi Sts only through your contributions, so keep the 1 etters coming. As you may recall , this newsletter originated as the R—390 User •s Group, and changed into the HOI low State Newsl etter with issue 4. So don •t forget to keep us informed of your experi ences with the R—390 and other industrial and military grade tube gear, e.g. , R-388, R-3B9, R-390A, R-S91, R-392, SP-600 (various models, including VLF) , any Collins or Racal, etc. We also need contributions on any and all consumer grade tube gear, including National , mmarlund, and Hal licrafters. And don •t forget tube type test gear. Some f our ham subscribers could al so tell us about hol low state transmi tters.

SEND BUT 1 NOW

COLL 1 NS D 1 IRE CAL F 1 L TERS

PART 1

Dal las Lankford

Col lins di sc—wire mechanical filters for communicati ons purposes are avail able in the frequency range of 60 — SOO khz with bandwidths of 0.2 — 16 khz. Most of those fi I ters operate at or near 455 khz . The fil ters come in three varieties: symmetric, USB, and LSE. The vast majority of such filters which are generally avai lable on the used and surplus market •are symmetric fi Iters. For tube type applications, source and load terminati ons of 100 K ohms or more ( >IOO K) are required. So our di scussi ons will be restricted to disc—wire, symmetric, 455 khz center frequency, > 100 K termination, Collins mechanical filters. Li sted bel ow are some common mechanical fi I ters of those kinds, and their speci f i cat i ons.

TYPE	PART NUMBER	PASS BAND ( khz / dB)	STOP BAND ( khz / db )	RES. CAP.
—N-20	526-9163-002	2.0/6	4. 0/60	110
F40U———N—40	526-9160-000	4.0/6	e. 0/60	110
	526-9161-002	8.0/6	16. 0/60	110
F 455—N-160	526-9162 _	16.0/6	32. 0/60
F450–FA-OS	526-9494—000		3. 0/60	130
F405—- FA-09	a. —9446—000	0.9/6	4.0/60	130
F4u5—- FA-IS	506—9495—000	1.5/6	3.5/60	130
F4S…J	526-9427—000		s. 3/60	130
F 405—	526-9500-000		6.2/60	130
F45S—FA-31	—9496—000	3. 1/6	6. 5/60	130
F 405—FA—4C)	526—9497—000	40 0/6	B. 5/60	130
	526-9498—000	6.0/6	12. 6/60	130
F4SS—FC-6C)	526-9522-001	6.0/3.5	25. 0/60	130
F4,.JU—Y-05	526-9521-010		3.0/60	130
F4SO	526-9337-000		5.3/60	130
F4S5— Y-31	526-9338-000		6.5/60	130
F4SS— 40	526-9339-000	4.0/6	e. 5/60	130
	526—9340—000	6.0/6	12.6/60	130
F4SS—Y-BO	526-9341-000	B. 0/6	1B.5/60	130
160	526-9343-000	16.0/6	27.5/60	130

N fi I ters are used in R—390A •s, and are perhaps the most common on the used ‘and surplus market. The last three digits of the part numbers of the N fi l ters may be different from the numbers gi ven above. Part numbers, pass bands, stop bands, and resonating capacitors values for the N filters are inferred from measurements, the 1970 NAVSHIPS manual drawi ngs and parts list, and individual filters markings. N filters have a metal case with flange. mount. Measured skirt attenuation i s typically well in excess of 100 dB.

FA fil ters originated in the early 1960’s as an “inexpensi ve” ham and experimenter filter, although some now sell in the $200 range for a new filter. They are occasionally available in Ham Trader Yellow Sheets for $30 — $60. FA fil ters have a plastic case, and it is important that the two ground I ugs have common si gnal ground. Measured skirt attenuation i s typi call y well in excess of 100 dB.

Y fil ters are seldom seen on the used and surplus market, and are included mainly for completeness. The Y case is a metal cyl inder, simi lar to the N case, but slightly smal ler, and with no flange.

Data for the FA and Y filters above is taken from various Collins publications. There i s also a series of FB filters which are identical to the FA filters above, except that the FB filters have measured pass band and stop band val ues marked on each fi l ter- Pass band and stop band lues may vary from filter to fi Itera The FA and Y values above are ni mum pass band and maximum stop band values respecti vely. For example, an indivi dual filter might typically have a 2.4/6 pass band and 4.6/60 stop band. Collins mechanical filters are very reliable, with a mean time before fai lure on the order of 2000 years based on field measurements. Insertion loss for the FA and Y filters is specified as 25 and 20 dB maximum respecti vely, but are typically much less, about B dB. I have no information about N filter insertion loss, but it is probably simi lar to FA and Y filter insertion loss,

THE O CONVERTER

Paul Gunn

Here is some information on what I think is one of the best units for SSE I have ever seen. The Hammarl und HC—IO converter is a compact uni t about 9″ wide, 9″ hi gh, and 7″ deep. It uses 10 tubes, and there are pl enty of controls for si gnal processing and shaping; SLOT FREQUENCY, SLOT DEPTH, AM & CW / SSE, PASSBAND TUNING, AVC OFF / SLOW / MED / FAST, POWER

OFF / ON, AUDIO GAIN, adjustable NOISE LIMITER, BFO tuning, SIDEBAND UPPER / LOWER / BOTH, and bandwidth O. S 1.0 / 2.0 / 3.0. The HC-IO is fed from the recei ver IF, and will accept any IF frequency between 450 and 500 khz. El completely agree with Paul that the HC—IO is an excel lent piece of equi pment It i s also ey:cellent for AM reception. The HC—IO is mainly the

60 khz IF strip, AGC, and audio circuit of an HO—IBO, preceded by a slot i l ter and converter which are adjustable in the 450 — 500 khz range. The —10 is easy to connect to an R—390A — you merely run a cable from the 455 z IF output (BNC connector) on the back of the R—390A to the input (RCA jack) of the HC—IO on i ts chassis rear. The HC—IO manual also describes how to connect it to some recei verse I have been very pleased with the HC— 10 when used with my R—390A. It provides more AM selectivity options than before (O. S, 3.0, and 6.0 khz at 6 dB down) , a slot filter for eliminating or reducing hets, and simplifies tuning SSB signals. I also find the audio quality of the HC—IO better (higher fidelity) than the R—390A. Ed.

SHORT 1 BUT 1 ONS

TORRESTRONICS TK-I DIGITAL DISPLAY KIT: 1 recently constructed the TK-I digital di splay kit for use with my HO—IBO. To minimize interference to the ‘ 180 1 had to build the buffer ampl i fier as recommended by Torrestronics. (Edward McFadden) [Would you mind sending an address for Torrestronics, and perhaps providing us with more detai Is? Ed.

POWER SUPPLY HASH: For i ndi vi duals who may have purchased 01 der tube type recei vers which have been converted to use a solid state 120 volt AC power , but seem unusually noi sy, try sol dering 0-01 mF 600 V (or more) disc capaci tors across each diode. Al so try soldering the same type capaci tors from each 1 eg of the AC 1 ine to recei ver/power supply chassis. This approach has worked well with power suppl i es for the BC—348, BC—453, and simi lar recei verso (Edward McFadden)

CEIVER DATA:

tic les are reprints and

For those interested i n modifying older receivers, a few avai I able through the National Radio Club. For a catalog of publications, send SO cents U.S. or 3 IRC’s to NRC

Publ icati ons, Dept. W, P.O. Box 164, Mannsville, NY 13661- The NRC

Recei ver Reference Manuals, Vols. 1 and 2, are $2.50 each, and contain all

sorts of i nformati on, i ncluding detai led revi ews of the R—38B and R—390A a survey of Hammarlund recei vers, construction and modi f i cation projects, and much more. (Wayne Hei nen)

AUDIO PROCESSING: You say that you are having trouble understanding the “muddy” audio with the 2 khz filter in your hol low state recei ver? My remedy is running the audio through a 10 band Radio Shack stereo equalizer, and then through a stereo amplifier. I can frequently improve intel ligibility by cutting down the bass, and raising up the midrange. My tape recorder is connected back through the amplifier using the tape moni tor button C? Ed. I equalize the audio I ‘m hearing, and the audio I ‘m taping, which permits me to equalize the audio on my playback of the taping. (Wayne Hei nen)

SATISFIED CUSTOMER: I finally came up with enough mad money to purchase an R—390A from Fair Radio after they sent me a flyer advertising excel lent, extra—cl ean units, checked, for $400 each. The unit I recei ved far exceeded my best expectati ons ! It is original in every sense, and appears to be unused. (Joe Bunyard, Nov D 84) C Thanks for the comments Joe. This kind of information is very useful. Let me add that I have generally been very sati sfied with my purchases from Fair Radio, and when there were probl ems with an order, they have always quickly and courteously corrected the probl ems. Fair Radio’s supply of R—390A’s fluctuates, and prices vary, depending on supply, demand, and equipment condi tion, so potential customers should write them for current prices and availability. Ed.

3TF7: Yes, we are still making a fuss about the 3TF7. Joe Bunyard noted in November 1984 that Fair Radio had a good supply at $10 each. Jay Mathi srud also noted last November that he was able to obtain ail R—390A tubes, including the 3TF7, for an average of $2 each, and suggests checking with different suppliers. In early 1985 my supplier, formerly D. R. P.

Electronics, was sold to Daily Electronics, and the price of 3TF7 ^es jumped from’ $2.50 to $10 each. I was also informed that when their current stock was depl eted, the price would rise to $38.900 (Dal las Lankford)

CAPEHART: As many R-390A fans know, Capehart assembled R-390A •s. But did you know that Capehart also manufactured jukeboxes and home phonograph systems, and that the founder, Homer E. Capehart, was a U.S. senator from Indi ana? (Jay Mathi srud)

DRAKE R—4C: The Drake R—4C is considered by many to be an excel lent recei ver E It sure is, see the receiver comparisons below. Ed. ‘. This last version of the 4—1 ine recei ver has 6 tubes and a number of semi conductors. It covers the ham bands, and has passband tuning. Radiokit, Box 411

Greenvi 11 e, NH 03048, (603) 878—1033, sells several modi ficati ons for the

R—4C, including a general coverage adapter kit, catalog i s 50 cents. R-4C’s are found at hamfests in the $200 range. Be sure to get the matching speaker. Earl ier ine recei vers (R—4/A/B) are I ess expensi ve. Drake still supplies parts and service for these recei vers- One QST ad suggests protecting your R—4C investment by installing a set of Tubsters for $138. A set of glass tubes can be gotten for around $12. Guess which i s the wi ser i nvestment? (Jay Mathi srud)

SOME MODIFICATION ARTICLES: In going over some of my remaining col lection of CQ magazines, I came across several articles which may be of interest to the gang. 1 . “Modifying the R390A/URR, ” CQ (Jan. 1965) , descri bes using a 7360 product detector, IF noise limi ter, and provisi ons to add a Q— mul tip 1 i era 2. “A product detector for mi I i tar y recei vers, ” CQ (Mar. 1967) , has step—by—step instructions for the R—3B8, and can be used for 7SA series or SIJ series mods. 3. “More on updated i mprovements

for the 51 J recei vers, ” CQ (Dec. 196B) , is an in depth article, quite good.

(Ed Kowal ski )

CHICAGO AREA NOVICE EXAM: 1 am a member of USAF MARS (Military Affiliate dio System) , and a ham radio operator. If any of the Chicago area aders would like to take their novice amateur radio exam, I am a qualified volunteer examiner and will be glad to give them the exam. To arrange an exam, write me at 8041 N. Haml in, Skokie, IL 60076—3403, and incl ude a phone number where you can be reached. We can then arrange for you to take the exam at my house. Have your appl i cation form from the FCC

in Chicago. You ‘I l get a 20 question multiple choice exam, and a 5 WPM

code test, no charge. (Larry Cotariu)

WANTED /

WANTED: Power transformer for R—3BB. Narr agansett, RI 02882.

WANTED: 51H recei ver C? Ed. ) in good, White, Box 1372, Burnsville, MN 55337. WANTED: Military gear: TRC-IO, PRC-I,

FOR SALE

Paul Zecchi no, 35 Pond Road ,

mint, or restorable conditi on. John

and MB”; al so origi nai manuals for

ARQ-I, and ARQ-B. Hugh Miller, 11206 – 1 NE, Seattle WA 98125.

WANTED: Q—mul tipi i er pl ans to add a notch to R—390A, and for exal ted carri er recepti on; a repl acement audio output transformer for a Hammarlund SP—200X and an RBC recei ver, Wayne Heinen, 4131 S. Andes Way, Aurora, CO 80013.

NTED:or HRO—SOO in good working shape, with manual , at a fair ice, Ed. Kowal ski , 3300 Chesterfield Road, Phi ladelphia, PA 19114.

SELL: Repl acement meters for R—3B9 and R—390A, $60 a pair, N. E. Litsche, P.O. Box 191, Canandaigua, NY 14424, (716) 394-014B Jay Mathisrud, who notes he has not tried the product].

EDITOR’S REMARKS: A good pl ace to buy, sell , and trade equipment and parts is the HAM TRADER YELLOW SHEETS, P.O. Box 356, Wheaton, IL 60189-0356: 24 i ssues (1 year) $10; mini —subscription $2 (4 issues) for potential subscribers. Among the best Q—multipl i er articles are CQ (Jan. 1955) , pp. 11-14, CQ (Mar. 1955) , pp. 29-30, 50, and QST (Apr. 1956) , PP. 39.

R–390A VERSUS 1 S

Dal las Lankford

If you have ever wondered how the R—390A dynamic range compares with other general coverage recei vers, Sherwood Engineering, 126B South Ogden St. , Denver, CO B0210, has provided some answers. The first page 0+ their general catalog lists 3B recei vers from which I have selected seven general coverage and seven Ham recei vers/transcievers, together with some of Sherwood s measurements,

The fol lowing abbreviati ons are used in the tables below; NF = noi se f 1 oor (dBm) B = blocking (dB) S = sensitivity (micro V) , FS = filter opband (dB) SS = test signals spacing, WDR = wide dynamic range (dB, kHz SS) , NDR — narrow dynamic range (dB, 2 khz SS) Sl – 100 khz SS, S2 – SO khz SS, = 5 kHz SS, S4 – 3 khz SS, = 2. S khz SS, F modified with Sherwood filter, Tl — receive tuning range 1 .5—5 and 6—30

T2 = recei ve tuning range 2—5 and 6—23 mhz , T3 receive tuning

GENERAL

COVERAGE RECEIVERS

range 3.4—5 and 6.5—29.7 mhz , H = Ham bands ^Ionly, andgeneral

Model	R-390A	NRD-SIS R-7 (A) FRS-7700 R-IOOO	NRD-93	R-70
	-137	-13B -135 -130 -130	-141	-129
B	130	103 145 123 119	12B	132
s	0.2	0. 1 0.3 0.2 0.2	o. 15 yeo	0.4
WDR		95 970 8302 76	94
NDR	79	77 75 6403 HAM RECEIVERS/ TRANSCIEVERS	63	620B
Model R—4CT		TS-B30^H901 -DM^HIC-720A^Ø	TS—82CP	75—S3BT3

coverage recei ve-

-i 39 -131 -129 -135 -137 -137 -146 133 117 122 124 13B 115 122

15 0.2 0. 1 o. 15 o. 15 0.2 0. 1

84 87 93 79

NDR 81 80 7B 7B 74

Dynamic range measurements were made using two equal strength test si gnals, nominally 20 khz apart for the wide measurements, and 2 khz apart for narrow measurements. In some cases, because of filter band widths or synthesizer noi se, wi der test si gnals separations were used. With al I other thi ngs being more or less equal, high narrow dynamic range is the deciding figure of merit for ranking a DX recei ver. Notice especially tha the wide dynamic range figures are frequently not good indicators of narro bandwi dth performance. As we see above, the R—390A wins first pi ace for narrow dynamic range performance against the best of recent solid state general coverage recei versa Sherwood Engi neering does not provide measurements for any other tube type general coverage recei vers-

1 SHER – S CORNER

Chris Hansen

Well, it’s back to the antique IBM as your Publisher welcomes Dallas Lankford as the new Editor of the Hollow State News letter. We hope to continue to serve you, but you have’ to cooperate. . . by contributing. Send your articles to Dallas at the address on the mas thead , Send address changes and subscriptions to Chris Hansen (me!) at the address also on the masthead. And now, the usual:

All articles and information shared through this news letter may be reprinted only with permission of the author. The publishing comrnittee assumes no responsibility for the accuracy or safety of untested modifications or the reliability of suppliers of services, parts, or equipment mentioned or advertised in HSN. HSN is available at the price of $4 for one year or $8 for two years. Frequency of publication is quarterly (roughly) by season. Back issues 1-2 and 4-10 are available from the publisher at $1 apiece. S les are available at the same price (the most recent issue will be sent), Inquiry sheets are available for a SASE. The above prices are for US/Canada/Mexico. Residents of other countries should double each price: $8 for one year, $16 for two, back issues $2, samples $2 or 4 IRC’s. Inquiry sheets available for 4 IRC’s,

NEXT ISSUE WILL BE THE WINTER “WONDERLAND” ISSUE. . . AVAILABLE AROUND JANUARY/FEBRUARY. HAVE A WONDERFUL DX SEASON, AND REMEMBER, YOUR CONTRIBUTIONS OF MATERIAL MAKE THIS NEWSLETTER POSS .

PHOLLOW

NEWSLETTER

EUEGB..L.E.LLQNE: $4 for one year (4 issues) , $8 for two years (B issues) , back issues $1 each (all currently avai i able) , send check or money order payable to Chris Hansen (address below) •

PUBLISHER: Chris Hansen, P.O. Box 1226, New York, NY 10159.

EDITOR: Dallas S. Lankford, P.O. Box 6145, Ruston, LA 71272-001B.

CONTRIBUTING EDITOR: Skip Arey, P.O. Box C-4, Cinaminson, NJ 08077.

The opinions expressed in The Hoi low State Newsletter belong to the divi dual contributors and do not necessarily reflect those of the edi tors or pubi i shera

MEET THE TUBE

Skip Arey

Greeti ngs campers. It is I your former Editor, turned Contributing Edi tor, and resident sage of tubetype i ore. Best of luck to our own Dal las Lankford as he renders forth with his edi toriai duties in the name of our obsession. This •pi sode of Meet The Tube brings us the 12SG7 or 12SQ7—GT. What? You don remember the tube?? Sure you do. Many of us encountered it or one 0+ the other twin— diode, high—mu, triode bottles as the main component of a code practice oscil Such a circuit using a 35Z5 rectifier is often found in the back of old RCA tube manuals. The metal type 12SQ7 and the gi ass—octal type 12SQ7—GT were used as combi ned detector, ampl i fi er, and AVC tube o O O in AC/DC radio recei verse Heater voltage is 12.6 volts AC or DC at O. 15 amperes. The only directly interchangeable tube for the 12SQ7 is the OBC3.

SHORT CONTR 1 BOT 1 ONS

R—390A PESIBN: The past week I recei ved a very exciting package in the mail which contained two Col lins engineering reports on the R–390 family of recei versa The reports have been reproduced and offered for sale by Frank eentges, AK4R, 9251 Wood ade Dr. , Breat Fai is, VA 22066. The engineering report on the design of the R—3B9, R—390, and R—391 is $15 postpaid, and the engineering report on the R—390A i $10. The first report contains all sorts of information, such as the development of the recei vers, why they designed them as they did, problems encountered and solutions, problems for future study, circuit descriptions and di scussions, and many photos. The report is about 3/8 inches thick. One example of what ‘s in the report — original specs cal led for the R–390 to be immersion proof . Initial tests found so much heat was generated inside the sealed cabinet that a cumbersome external cooi ing system was needed. Subsequently, this spec was dropped by the Signal Corps, and a separate recei ver, the R–392, was devel aped to meet the requirement. This report was just declassified in May through Frank Gentges’ efforts, and he deserves a pat on the back and a 3TF7 taking the initiative to reproduce these fine documents. The second report is mainly a Coli ins study to reduce the cost of the R–390, resulting in the R—390A. Again, lots of detailed information and photos. These reports are a must for the R—390 affieionado — fascinating reading, well worth the price. (Jay Mathi srud) t I certainly agree with your comments about these reports from what I have seen. The second report i s titled “Cost Reduction Program For Radio Receivers, ) /URR, ” Final Progress Report, Period Covered To: 20 Feb. 1956. The report is 31 pages of single spaced text, Pius 2B pages of pictures (35 figures) . From

comments in the text it is apparent that the period covered is actually to about Sept. 1956. Also, five figures are missing: functional di agram for the mechanical tuning of the R—390A and R—391A, schematics far the R— 390 (XC—3) and R—39i (XC—2) , and the final cost anal ysis for the R—390 (

) /URR. I guess the government is still keeping some details secret. (Ed. )

AM PRESS/ EXCHANGE: The AM Press Exchange i s the only amateur radio publ ication devoted to amplitude modulation. Each month there are articles on AM transmi tters, older receivers, surplus conversions, AM happenings on the Amateur bands, and free ads. It also keeps AM operators informed of threats to their operating privileges. Sample copies are $1, and subscriptions $9, from AM Press Exchange, Route 1, Box 281, Woodi awn, TN 37191. (Jay Mathi srud)

E….NU…..–…………—.-B-…-S: (1) Mike Consalvo, 721B Roanne Drive, Oxon Hill, MD 20745, send SASE for current list, (2) Wayne D. Russell , 9410 Walhampton Dr. , Loui svilie, KY 40222, send SASE for current list, (3) Military Technical

Manual Service, P.O. Box 15062, Long Beach, CA 90915—0062, send $3 for a 60 1

page catal (Joe Bunyard)

3TF7. PRICES: As of November 12, 3TF7 e $15 each, 26ZSW e $5 each, from Daily Elecrtonics, P.O. Box 5029, Compton, CA 90224. (Joe Bunyard)

ElJ_QUEä: Antique Radio Classified, 9511 Sunrise Blvd. , J – 23, Cleveland, Ohio 44133 publ ishes a very nice bui letin, $12 per year (12 i •sues) . The two issues I have recei ved so far were 24 pages each of reduced type, simi lar in format to many M” and SW club bulletins. The print quality and layout is very well done. A bul letin typically contains about half wanted/ for sale ads, and about half articles with pictures. Picture quality is excel lent. Emphasis seems to be on radio recei vers of the 1920 •s and 1930 •s, but tubes, speakers, headphones, and other parts ar also incl uded. If you are interested in anti qua radios, write them for

information and a subscription form. The information packet I recei vod also contained an address list of anti que radio clubs throughout the USA. In case you didn ‘t know, two useful guide books for anti que radios and parts are Vintage Radio, 1887 — 1929, and A Flick Of The Switch, 1930 — 1950, by M. E. McMahon. Both books are available for $9.9S each, plus ostage, •from Fair Radio, P.O. Box 1105, 1016 E. Eureka St. , Lima, Ohio

802, phones: 419/223-2196, and 419/227-6573. (Dallas Lankford)

PARTS SOURCES: (1) Electronictown, Inc. , 440 7th Ave. , P.O. Box 204B, San Diego, CA 92112, phone: 714/232-9379, ATTN: Murray Anker, very helpful on mil i tar y gear, has tubes, connectors, etc. , reasonable pri ces, (2) Unity Electronics, Inc. P.O. Box 213, 107 Trumbull St. , Elizabeth, NJ 07206, phone; 201/351-4200 and 212/571-oe70 for information, or 1-800/6317346 to pl ace an order (Joe Bunyard)

R-390A METER LIGHTING: I was unhappy with the lack of meter lighting in my R—390A, and feel ing adventurour, I instal led small S volt SO ma lamps inside the meter cases. A schematic of the meter i ighting mod is given bel ow. First, remove the metersfrom the receiver, tagging I eadse This can be done wi thout removing the front panel with patience. Remove the front pl ates from the meters, and then gently remove the circular glass plates. They may be cemented, so be careful not to break the glass. I used a tiny jeweler ‘s screwdriver to gently pry the glass plates loose. After the glass plates are removed, the meter movements can also be removed and set

aside out of danger.

In my meters it was necessary to clip off a small appendage on the 6.3 VAC movement spring to make room for the i amp near the very front of the case.

A smaii hole is drilled through the ar of the metal meter case for the re and i amp instal iation. 1 took AC power from the low vol tage end of R124 which is a dropping resi stor far the main dial lights. It is located on TBIOI on the front panel, and the connection can be made without front 50 MA panel removal . I used a series connection with a 12 ohm 1/2 watt series dropping resistor, hoping to reduce any heat generated (none is apparent) , and obtain long lamp life since repl acing them will obviously be a pain. I placed the 12 ohm resi stor

at the end of the line, and grounded is to a solder lug attached to the line
I evei meter mounting screws. Paint on the front panel must be scraped off to	P liq-q	POSITION

101

make a good el ectrical contact. Whew! It sounds complex, but it isn •t — just R don ‘t try to hurry. (Gerald Murphy)

6800

R-390A SPEAKER DISCONNECT: The original phone jack on the front panel can be repl aced speaker di sconnect jack. Just nsoider the wire from position 6 0+ moa

102 and run two switching wires to he front panel along the partition between the PTO and AF sections.

(Gerald Murphy)

R-S90A EXPERIENCES: Greetings from a R-390A afficianado. 1 am typing this from my home located on a salt pond in a marshy area near Narragansett, RI Reception here i s nothing short of excel lent. Equipment presently includes two R—390A’s and three R—3Be ‘s, and antennas are numerous ongwires and whips. There are ai so a few scanners, and the obligatory CG and Ham rigs. The 390 •s cap a dream I •ve had since being exposed to them at a Navy COMMSTA twelve years ago. Both came from Fair Radio Sales. One i s built by EAC, vintage 1960, and has always been good. The second was built by Motorola, ventage 1956, and has been to say the least been a dog. A 390 isn ‘t much to brag about if its sensitivity is only capable 0+ pul ling in the local AM ‘er on a twh hundred foot long wire. Si nce it was sold “checked” by Fair, and they are very good about that, I

started digging. t I wasn ‘t under the impression that Fair was ail that thorough, with “checked” meaning “someone turned it on and it seemed to work OK” A iot may be left for the customer to do, as is related in this experience. Ed. 2 Of course, ail tubes checked fine on a commercial tube tester, and about half later proved to be bad. I shudder to think how many tubes I •ve chucked out because the tester said they were “bad. ‘t The only way i s to substitute with a kno*l good tube. However, sensitivity was still poor, and improved only slightly after al ignment. Selectivity. and stability were excel lent. Then I read the HSN suggestion about substi tuting a 6BA6/S749 for the ‘DC’ RF amp (V201) • With this change, sensitivity improved dramatically. I made the substitution on the other rig with even better results. Al so, for greater audio gain, I substituted 12AT7’s for 12AX7’s t5B14A’s ? Ed. ‘ in the audio module. And one night while rummaging through a tube treasure box given me by my fine lady friend, I located several ‘J’/ 6101 tubes. These are twin triodes simi lar to the 6C4 mixers in the R—390A. I used 636 ‘s for V203 and V204, and wham, signals were jumping out of the set with formidable power. The substitute tubes run plenty cool, and there is no strain on the receiver.

Zecchi no)

I recently bought a much used HQ—ISO, IBOS, and made a few mods. The first priority was getting rid of the SU4—GB, and i ts fteen watts of heat. I couldn •t find any 2000 volt solid state diodes, so I went with RCA ‘s rated at 1000 V 3 A, mainly because it seemed they would di ssipate heat better than the 1 A units. The diodes were mounted topside using subminiature phone plugs soldered to one end each of the diode leads. These are then plugged into the SU4 socket at pins 4 and They just fit. The other ends are tied together and go to a 250 ohm 20 W resi star, again mounted topside with a 8/32 bolt through the center and chassis about 3/4 inch in front 0+ the 5134 socket. From the other end of the power resi stor, another lead goes to another subminiature plug, which in turn goes to pin 2 of the StJ4 socket. The B+ voltage was about 275 before the mod, and about 260 after the mod. The power resi stor di ssi pates about 4 W, so the mod should run cooi and last. (Ai Merri 1 i)

DI SC—WIRE F 1 L TERS

Dai las Lankford

There is apparently no uni versaiiy agreed upon schematic symbol •for mechanical filters, so we have adopted the symbol bel ow.

The FA, FB, and N series filters ail have

3 lugs at the input and output. Apparently it does not matter which end of these + i iter is used as input or output. The filters can be connected for bal anced or unbal anced operation at input or output.

There are two basic mechanical filter circuits, depending on whether AVC feed i s series or parai lei, which are shown below. L is an RFC choke of about 10 mH (the R—390A uses 12 mH) , RI is the usual B+ line resi stor (2200 ms in the R—390A) , Ct are the terminating capaci tors, including stray paci tance, which depend on the filter (130 pf for FA and FB filters, and 110 for N series filters) , R2 is part of the AVC circuit (22K in the R— 390A which uses parallel AVC, and 100 K in an HQIBO (A) which uses series AVC) , and R3 is part of the series AVC (100 K for an HQ—IBOA) . The terminating capacitors Ct usually consist of a fixed mica in paral i el with a 50 pf trimmer so that filter response can be optimized. In early -R— 390A’s, only fixed 110 pf micas were used, while in later R—390A’s fixed B2 pf micas in parallel with SO pf trimmers were used for the 2, 4, and B khz bw f i i ters, and a fixed 51 pf mica in parallel with a 50 pf trimmer was used for the 16 khz bw. Some other arrangements are also possible. Recently I encountered B and 16 khz bw filters made by Motorola (with a yel low label) which used no fixed mica, and which were tuned to resonance with only the SO pf trimmers. I have used the FA series filters in one of my HQ—1BOA’s with fixed 100 pf micas in parallel with SO pf trimmers. Ali capaci tors should be rated at least 500 VDC. The o e 01 mf filter input ground capacitor in the circuits below is my “fai I—safe” mechanical filter protection mod. Together with the 0.01 coupling capacitor, it provides double protection of the filters from B+ vol tage which would otherwise wipe

For current new prices (be prepared for a shock) and information on mechanical filters, write to Rockwell International , Electronic Devices Division, 4311 Jamboree Rd. , P.O. Box C, Newport Beach, CA 92660. Refer to 526 part number only. Used and unused f i are occasionally avai i able in the Ham Trader Yel low Sheets in the $20 — $50 range. A complete set of

four N—sories fi i ters (plus a lot of other R—390A spare parts) can be obtained from Baytronics by buying their incomplete R—390A for $75 Pius shipping (sans meters, PTO, and power supply) • If you already have an R— 390A, the filters can easily be checked by pulling the IF subchassis from the Baytronics unit, and putting it in your R—390A. The incomplete

Baytronics unit represents .a very good value for someone who wants several filters with a wide range of bandwidths. And for the adventurous, the R— 390A swi tching could be reused to add multiple mechanical filters to another recei ver. Or if one of your + i iters is weak (has excessive loss) , you mi ght want to trade i t out. + i iters are also sturdier than the others, and so are better suited for the experimenter

• S CORNER

Chris Hansen

Hi there, all you potential contributors ! ! Dallas is one of the best writers in the hobby today, and we ‘ve got him here, but he can’t do it all alone. If we were to add one issue to the subscription of every contributor to the Spring 1986 issue, would you go to your (typewriters/ legal pads /brown paper bags) and write something??? PLEASE! Seriously, we need your input to make HSN a bigger success than it already is, We await your contributions, and we will indeed add one issue to the subscription of

1 1

EVERY contributor, whether we use it in the spring issue or keep it in the bank for later when we are DELUGED with articles . On another subject, yours truly is going to survey tube retailers for the next issue of HSN, We ’11 have our Second Sort-Of-Annua1 Gaia Tube Issue at last! ! ! I ’11 try to get addresses, payment/ refund policies, and sample prices for tubes we all need and want. Look for it! I am in need of the knob for the BN Pitch control on my R390A and also the cable which goes from the IF stage to the IF Output jack (J 116) on ehe rear pane of the R390A. Naæ your price or I’ll trade a set of two meters for your R390/R390A in mint condition with hardware. Two other pairs are for sale. Contact your publisher at the address on the front of the newsletter. 1

AND WW, TIE USUAL: All articles and information shared through this news letter may be reprinted only with permission of the author. The publishing comiteee assumes no responsibility for the accuracy or safety of untested modifications or the reliability of sup- pliers of services, parts, or equipment mentioned or advertised in HSN, HSN is available at the price of $4 for one year or $8 for two years, Frequency of publication is quarterly (roughly) by season, Back issues 1-2 and 4-11 are available from the publisher at $1 apiece, Samples are available at the same price (the most recent issue will be sent), Inquiry sheets are available for a SASE, ‘me above prices are fot US/Canada/Mexico residents of other countries should double each price : $8 for one year, $16 for two, back issues $2, samples $2 for 4 D.C ^ts. Inquiry sheets available for 4 IRC’s, Please make all checks/money orders payable in US, currency to “Chris Hansen” BSN is not yet big enough for its own bank account,

FROM MY R390A MANUAL: Demolition of Material to Prevent Enemy Use: 11, 172: Methods of Destruction: Use any or all of the methods listed in a through f below to make the equipment completely useless a, Smash, Shash the controls, tuning mechanism, tubes, . . , b, Cut. Cut the power cord, the antenna lead in cable; use an axe, a handaxe, or a 1 mache te . c, Burn, Burn cords, cables, and manuals; use gasoline, kerosene, oil, flamethrowers, or incendiary grenades . d, Bend, Bend the panel, the cabinet, and the main

throw them into streams . . o: frame , e. Explos Ives If explosives are necessary, use firearms, grenades, or TNT,

Disposal, Bury or scatter the destroyed parts in slit trenches or fox holes, or

PI.EASANT DREA>S FROM: