Collins Collectors Association
Technical Bulletins, Archives, and Community Resources — A Practical Guide
The Collins Collectors Association (CCA) is the primary preservation organisation for Collins Radio technical documentation. It holds an active licence from Rockwell Collins to reproduce and disseminate Collins copyrighted materials related to amateur radio products — the only organisation with that authority. This guide maps every CCA resource, explains what is behind the member portal and what is open, and points to the key external resources that every Collins owner and restorer should know.
The Collins Collectors Association (CCA) is a non-profit, all-volunteer organisation dedicated to the preservation, documentation, and community support of Collins Radio equipment. Founded and operating through collinsradio.org, the CCA holds a unique licence from Rockwell Collins to reproduce and distribute Collins copyrighted technical documents — covering not only amateur radio products but all Collins commercial and military equipment usable for amateur radio purposes. For any serious S-Line, KWM-2, 51J, or 75A owner, the CCA website is the single most important online resource.
This guide documents every CCA resource category, the current Technical Bulletin series, the complete KWM/HF-380 service bulletin listing, the archive structure, the key external resources, and how membership relates to access. All URLs were verified against the live site in April 2026.
The CCA is licensed by Rockwell Collins “to reproduce and disseminate in electronic and written format, any such Collins copyrighted documents related to Collins amateur radio products. Such documents include, but are not limited to, product manuals, schematics, test methods, service bulletins, advertising materials, product catalogs, maintenance information and other technical and product information related to Collins amateur radio products.” Rockwell extended the licence in 2001 to include all Collins commercial and military equipment usable for amateur radio purposes. This licence is what makes the CCA archives legally distributable; without it, sharing this documentation would be a copyright matter. Supporting the CCA through membership directly supports the continuation of this licence and the ongoing digitisation work it enables.
Section 1 — CCA Technical Bulletins
The CCA Technical Bulletin series addresses specific knowledge gaps for Collins equipment owners and restorers. As of April 2026, two bulletins have been published. Full downloads require CCA membership; the bulletin titles and topics are publicly listed.
Access: collinsradio.org/listing-of-cca-technical-bulletins/ (member login required for downloads)
- Topic area
- Collins S-Line transmitter protection
- Relevance
- Addresses the well-documented but poorly understood transmit spike phenomenon in the S-Line transmitters (32S-1/2/3/3A and KWM-2/2A). Transmitter spikes are a leading cause of damage to downstream equipment and linear amplifiers in S-Line stations. This bulletin is essential reading before connecting an S-Line transmitter to any solid-state amplifier or SDR front end.
- Access
- CCA membership required for download. Title confirmed at collinsradio.org.
- Topic area
- Collins mechanical filter identification and specifications
- Content
- Reprints the original Rockwell International specification sheet 526-9605 (Electronic Systems Group, released 20 May 1982, 7 sheets) in full. Covers the upper sideband mechanical filter with 456.45 kHz centre frequency and 1.7 kHz bandwidth — the filter used in later Rockwell Collins commercial and military equipment that may be encountered in late-production KWM-2A units. Also includes the complete Collins mechanical filter general catalog page (all 455 kHz filter types) and the Collins case style drawings with confirmed physical dimensions.
- Why it matters
- The 526-9605 spec sheet was not publicly available before TB-2 reprinted it. It established corrected test conditions for this filter (3 V RMS max input and 100 kΩ source/load — quite different from the standard S-Line 2 V / 5 kΩ figures), the operating-temperature electrical performance column, the three dash-number variants (-010, -020, -030), and Case Style I physical dimensions. The catalog page confirmed several N-case and FC-case part numbers not previously documented in public amateur radio references.
- Access
- CCA membership required for full download. The filter specification is also available via the CCA Collins Technical Archives PDF linked at collinsradio.org (TB-2 PDF) — verify current link status as archive URLs may change.
Section 2 — Collins Radio Service Bulletins and Information Letters
The CCA has digitised the original Collins Radio factory service bulletins and service information letters (SILs) covering the KWM/HF-380 transceiver series and S-Line equipment. These are the documents Collins issued to authorised service agencies to address known issues, modifications, and improvements. They are the closest thing to factory engineering direction that exists for this equipment.
Access: collinsradio.org/cca-collins-technical-archives/collins-radio-service-bulletins-and-information-letters/ (member login required)
KWM / HF-380 Series Service Bulletins
Bulletin |
Description / Purpose |
|---|---|
| SB-1 | Transceiver interconnect cable |
| SB-2 | Correct MIC audio at output |
| SB-3 | Correct PBT operation |
| SB-4 | Improve 160-metre transmit |
| SB-5 | Reduce 2nd harmonic of transmitted carrier |
| SB-6 | Improve ALC time constant |
| SB-7 | Add transceiver relay driver output |
| SB-8 | Improve frequency display |
| SB-9 | Stop PA oscillations |
| SB-10 | Add WARC band transmit |
| SB-11 | Add receiver low-pass filter |
| SB-12 | CW waveshape improvement |
| SB-13 | Improve receiver AGC action |
| SB-14 | Ensure transmit audio response |
| SB-15 | Add anti-static discharge path |
| SB-16 | Improve frequency synthesis |
| SB-17 | Add external tune line for CU-380 |
| SB-18 | Eliminate RF pulse |
KWM / HF-380 Service Information Letters (SILs)
SIL |
Description / Purpose |
|---|---|
| SIL 1-81 | Provide mute function for external receiver |
| SIL 2-81 | Connections to Collins S-Line phone patches |
| SIL 1-84 | Product improvement — remove RFI susceptibility on microphone input and speaker talk-back during transmit |
Accessory Service Bulletins (CU-380 / Noise Blanker)
Bulletin |
Description |
|---|---|
| AC-3803-SB-1 | Control Interface CU-380 — improve RFI filtering and coupling |
| AC-3801-SB-2 | Noise Blanker — improve performance and add blanking |
Section 3 — Amateur Service Agency Bulletins
The Amateur Service Agency Bulletins are a separate archive from the factory service bulletins. These were issued by Collins Radio to its network of authorised service agencies and cover modifications and fixes across a wider range of equipment than the KWM/HF-380-specific service bulletin series. The CCA has digitised this entire archive with permission from Rockwell Collins.
Access: collinsradio.org/cca-collins-technical-archives/amateur-service-agency-bulletins/ (member login required)
The Amateur Service Agency Bulletins contain many of the factory-directed modifications that experienced restorers have been implementing from printed documentation for decades — but in their original factory form rather than as community interpretations. For equipment like the 75S-3 receiver, the 32S-3 transmitter, and the 75A-4, these bulletins can resolve long-standing questions about whether a modification found in a unit was factory-sanctioned or a previous owner’s work. This distinction matters for both restoration decisions and equipment valuation.
Section 4 — CCA Collins Technical Archives
The CCA Technical Archives are the heart of the collinsradio.org resource structure. The archive is divided into a Technical section (operational and service documentation) and a Historical section (company history, equipment history, people). The Technical archives are the primary destination for restorers and operators.
Archive home: collinsradio.org/cca-collins-technical-archives/
collinsradio.org → Equipment Manuals
collinsradio.org → 1959 and 1964 Catalogs
collinsradio.org → Service Bulletins & SILs
collinsradio.org → Fundamentals of SSB
collinsradio.org → Collins Surveys
collinsradio.org → Collins Signals 1930s
Section 5 — CCA Collins Historical Archives
Separate from the technical archives, the CCA maintains a historical archive covering the company, its equipment, and its people. This section is particularly valuable for understanding the context behind the engineering decisions in the equipment being restored.
Historical archive home: collinsradio.org/cca-collins-historical-archives/
Section |
Content |
URL |
|---|---|---|
| Company History | Corporate history of Collins Radio from Arthur Collins’ early experiments through the Rockwell acquisition and beyond | collinsradio.org → Company History |
| The Equipment of Collins Radio | Equipment-by-equipment historical documentation including photographs; includes the pre-war historical equipment section with early Collins gear | collinsradio.org → Equipment History |
| The People of Collins Radio | Profiles of the engineers, designers, and leaders behind the Collins product line | collinsradio.org → People of Collins |
Section 6 — CCA Signal Magazine, Nets, and Community
CCA Signal Magazine
The CCA Signal is the association’s quarterly full-colour publication, distributed to members. Back issues through approximately 2013 are available as scanned PDFs to all visitors without login.
Access: collinsradio.org/signal/
The pre-2013 Signal back issues contain a significant body of technical articles, restoration accounts, equipment surveys, and community knowledge that predates the modern internet forum era. Many restoration techniques in common use today were first documented in Signal articles. The scanned PDFs are searchable and represent a substantial supplement to the formal technical archive.
CCA Weekly Nets
The CCA operates several weekly nets for technical discussion and equipment trading. These are a direct channel to experienced Collins owners and restorers.
Net |
Focus |
|---|---|
| Sunday Net | Dedicated to technical discussion and Collins equipment buy/sell/swap listings |
| Three Weekly 75-Metre Nets | Informal open discussions; general Collins topics |
| Theme Weeks | Popular scheduled events focusing on a specific piece of equipment or technical topic; dates announced on the reflector |
Net schedules and frequencies: collinsradio.org/information/cca-nets/
CCA Reflector
The CCA operates an email reflector for ongoing community discussion. Past postings are archived and searchable through the listserve.com provider. The reflector archive at mailman.listserve.com/pipermail/collins/ is publicly accessible without membership and contains an enormous depth of technical discussion accumulated over decades. If you have a specific technical question about Collins equipment, searching the reflector archive before asking is strongly recommended — the probability that the question has already been addressed thoroughly is high.
Reflector subscription and information: collinsradio.org/information/cca-reflector/
Section 7 — Additional Resources: RX For Your Collins, CCA Grading Standards, and External Sites
RX For Your Collins
A dedicated resource section on the CCA website covering receiver-specific restoration and operational guidance. Access at collinsradio.org/rx/.
CCA Equipment Grading Standards
The CCA publishes a standardised grading system for Collins equipment condition assessment. Using the CCA grading scale when buying, selling, or describing equipment provides a common reference that is understood across the community. Access at collinsradio.org/information/gradingstandards-thks-gary/.
Electric Radio Magazine — Collins Compendiums
Electric Radio (ER) magazine produces the Collins Compendiums — three-ring-bound reprints of all technical service bulletins for the S-Line, KWS-1, and 75A-4 (three volumes). These are the printed equivalent of the CCA’s digitised service bulletin archive and are valuable for bench use where a printed reference is preferable to a screen.
Item |
Detail |
|---|---|
| Collins Compendiums | Three volumes: S-Line, KWS-1, and 75A-4 service bulletins in binder format. Available from Electric Radio. |
| ER Magazine subscription | US$34/year domestic; US$45/year first class. Editor: Ray Osterwald N0DMS. |
| Website | ermag.com |
Section 8 — Complete URL Reference Table
All URLs below were verified against the live collinsradio.org site in April 2026. Some sections require CCA member login for full content access.
Resource |
URL |
Access |
|---|---|---|
| CCA Home | collinsradio.org | Public |
| Technical Bulletins listing | collinsradio.org/listing-of-cca-technical-bulletins/ | Titles public; downloads member only |
| Technical Archives home | collinsradio.org/cca-collins-technical-archives/ | Index public; content member only |
| Equipment Manuals | collinsradio.org → Equipment Manuals | Member only |
| Service Bulletins & SILs | collinsradio.org → Service Bulletins | Member only |
| Amateur Service Agency Bulletins | collinsradio.org → Service Agency Bulletins | Member only |
| 1959 and 1964 General Catalogs | collinsradio.org → General Catalogs | Member only |
| Fundamentals of SSB | collinsradio.org → Fundamentals of SSB | Member only |
| Rod Blocksome’s Collins Surveys | collinsradio.org → Collins Surveys | Member only |
| Collins Signals 1930s newsletters | collinsradio.org → Collins Signals 1930s | Member only (watermarked previews public) |
| Historical Archives home | collinsradio.org/cca-collins-historical-archives/ | Partial public access |
| Signal Magazine archives | collinsradio.org/signal/ | Back issues to ~2013 public; current member only |
| RX For Your Collins | collinsradio.org/rx/ | Public |
| CCA Grading Standards | collinsradio.org → Grading Standards | Public |
| CCA Nets | collinsradio.org/information/cca-nets/ | Public |
| CCA Reflector | collinsradio.org/information/cca-reflector/ | Public subscription info; archive public |
| Reflector archive | mailman.listserve.com/pipermail/collins/ | Public; searchable |
| Favourite Links | collinsradio.org/information/favorite-links/ | Public |
| CCA Membership | collinsradio.org/membership/ | Public |
| Electric Radio Magazine | ermag.com | Public; subscription US$34/year |
| WA8DBW Collins page | wa8dbw.ifip.com/CollinsRadio.htm | Public |
| QRZ Collins Forum | forums.qrz.com | Public (search “Collins”) |
Section 9 — CCA Membership: What It Provides
CCA membership provides access to downloadable Technical Bulletins (currently TB-1 and TB-2), the full Collins Radio Equipment Manuals archive, the complete Service Bulletins and Information Letters archive, the Amateur Service Agency Bulletins, the 1959 and 1964 General Catalogs, the Fundamentals of Single Side Band document, the Collins Surveys, the Collins Signals 1930s newsletters in full resolution, current Signal Magazine issues, and full-resolution historical archive images. Membership also supports the ongoing digitisation and preservation work and the CCA’s continued licence agreement with Rockwell Collins that makes all of this legally distributable.
Membership information and registration: collinsradio.org/membership/
The site is operated and maintained by Scott Kerr KE1RR of TrackerSoft LP. The CCA Board of Directors is listed at collinsradio.org/information/board-of-directors/. The organisation is a non-profit run entirely by volunteers with a genuine passion for Collins Radio preservation.
Sources and Notes
- Collins Collectors Association website, CCA Collins Technical Archives — About the Licence. The Rockwell Collins licence text quoted in Section 1 is reproduced from the archive home page. collinsradio.org/cca-collins-technical-archives/. Verified April 2026.
- Collins Collectors Association, Technical Bulletins Listing. Confirmed two bulletins (TB-1 and TB-2) as of April 2026. collinsradio.org/listing-of-cca-technical-bulletins/.
- Collins Collectors Association, Collins Radio Service Bulletins and Information Letters. Service bulletin and SIL titles confirmed from the CCA archive index. collinsradio.org.
- Collins Collectors Association Technical Bulletin TB-2, Collins Radio Mechanical Filters Specification 526-9605, Issue 2, October 26, 2024. Primary source for the mechanical filter specifications documented in the vk6ada.com.au Collins S-Line and KWM-2 Filter Comprehensive Guide. The corrected test conditions (3 V input, 100 kΩ source/load), operating temperature performance column, dash number variants, and case style physical dimensions were all sourced from TB-2.
- Electric Radio Magazine. Collins Compendiums and publication details confirmed at ermag.com.