vk6ada.com.au • Collins R-390A/URR Technical Series R-390A/URRFailure Prevention Kit — Component & Modification Design A complete engineering analysis of the ten predictable R-390A failure modes, with a structured two-tier component replacement kit and four preventive circuit modifications to eliminate them…
vk6ada.com.au • Collins S-Line Technical Resources Collins Radio Equipment ManualsCCA Technical Archive Directory A complete mirror index of all Collins Radio equipment manual PDFs hosted by the Collins Collectors Association. Links open directly on the CCA server. No login required.…
vk6ada.com.au • Collins S-Line Safety Series Collins 516F-2 & S-LineThe Switched Neutral AC Power Design Defect A comprehensive guide for operators worldwide: why the 516F-2 presents a live mains hazard when switched off, how mains voltage, plug polarity and wiring…
vk6ada.com.au • Collins KWM-2 Technical Series Collins KWM-2 / KWM-2AVietnam Modification (SCED 11b) Complete process plan — PTO voltage stabilisation using a 150 V zener diode. Includes parts list with suppliers, step-by-step installation procedure, Quality Assurance plan, and pre-power test protocol.…
vk6ada.com.au • Collins Radio Heritage Series • Second Edition Prolific Authors ofCollins HF Radio Equipment Eight writers who documented the most revered name in amateur radio — from circuit notes to biography, from service bulletins to space history. All known…
Collins KWM-2 PTO Frequency Jump Troubleshooting Guide By VK6ADA • March 25, 2026 This guide documents the troubleshooting process for an intermittent 9 kHz frequency jump in a Collins KWM-2/2A transceiver that occurs after 1-2 hours of operation. Based on…
Wulfsberg Electronics & Collins Radio:Research Note — Second Edition Paul Wulfsberg • P.G. Wulfsberg at Collins Radio, Cedar Rapids (IEEE, 1963) • Paul Wulfsberg at King Radio (NASA, 1970) • Arthur F. Wulfsberg at Collins Radio (Apollo) • K.N. Wulfsberg…
Collins Radio Avionics —Historical Introduction Dates & Archive Resources Collins • 618M • 860E-1 (1961) • 51R-7A • VIR-30 • DME-40 • 51RV • ARINC 410 • Pro Line I / II / 4 / 21 / Fusion • EFIS-85/86…
Collins KWM-2 / KWM-2ARestoration Deep-Dive Arthur Collins’ Masterpiece • 1959–1977 • The Compact S-Line That Went to War Of all the rigs to emerge from Cedar Rapids, Iowa during the golden age of amateur radio engineering, the Collins KWM-2 occupies…
Alpha 87A Linear Amplifier:Restoration & Service Guide 3CX800A7 Tubes • PIN Diode T/R Switching • Microprocessor Control • Fault Code Reference • Cabinet & Safety 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 1,500 W Continuous — 3CX800A7 💻 Microprocessor Controlled…
Alpha / ETO 91B Linear Amplifier:Restoration & Service Guide 4CX800A/GU74b Tetrodes • Grounded-Cathode Grid-Driven • Vacuum Relay QSK • Electronic Bias System • Cabinet & Safety 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 1,500 W — 4CX800A/GU74b Tetrode 🇧🇬 Assembled…
Alpha 9500 Linear Amplifier:Restoration & Service Guide 3CX1500A7/8877 Triode • Five I²C Microprocessors • Auto Mains Tap • Gigavac Vacuum Relays • Three Stepper Motors • Cabinet & Safety 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 1,500 W — 3CX1500A7/8877…
Alpha 8410 Linear Amplifier:Restoration & Service Guide 4CX1500B Bayonet Tetrodes • Manual Tune • Swamped-Grid Input • EBS • PIC Microcontroller • Dual Input Match Relay • Cabinet & Safety 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 1,500 W —…
Emtron DX-1A Linear Amplifier:Restoration & Service Guide GU74B (4CX800A) Tetrode • AMPC Control Board • TRIAC Soft-Start • EBS Jumper • Optional Jennings QSK • Emona Electronics Sydney • Cabinet & Safety 📝 VK6ADA Technical Papers 📅 March 2026 ⚡…
Emtron DX-1D Linear Amplifier:Restoration & Service Guide GU74B (4CX800A) Tetrode • RF Sub-Chassis & 9-Way Connector • Dedicated Display Board • SWR Protection • AMPC Control Board • TRIAC Soft-Start • TDA1085C • Dual Tank Coils • Emona Electronics Sydney…
Emtron DX-1SP Linear Amplifier:Restoration & Service Guide FU-728F (4CX1500B-class) Tetrode • 1,200 W CW / 1,500 W PEP • 8× 470 μF/500 V HV Bank • 40 A TRIAC Soft-Start • Dual-Polarity Screen Protection • Eimac 4CX1500B Compatible • OCC • FCC Approved 📝 VK6ADA…
Emtron DX-1V Linear Amplifier:Restoration & Service Guide 6-Metre (50 MHz) Specialist Variant • GU74B (4CX800A) Tetrode • Single-Band 50 MHz Pi-Network • AMPC Control Board • TRIAC Soft-Start • QSK Standard • Emona Electronics Sydney 📝 VK6ADA Technical Papers 📅 March 2026…
Emtron DX-2 Linear Amplifier:Restoration & Service Guide GU84B (4CX2500A) Tetrode • 27 V Heater • 1,500 W Carrier / 7 Bands • Ferrite Toroid “L” Coil • Two-Speed Blower • Ig2+/Ig2− Screen Current Metering • RF Sub-Chassis • 9-Way Connector • Emona…
Emtron DX-2A Linear Amplifier:Restoration & Service Guide GU84B (4CX2500A) Tetrode • 9-Band Full Coverage (160m–10m incl. WARC) • RF Module Schematic in DX-1D Documentation • Two-Speed Blower • Dual Temperature Sensors • All-Band Tank Circuit Upgrade • Emona Electronics Sydney…
Emtron DX-2SP Linear Amplifier:Restoration & Service Guide GU84B • 2,000 W Carrier / 2,500 W PEP • 4 kVA Transformer • Heavy-Duty H.V. Band Switch • Horizontal AMPC Board • Dual-Polarity Screen Supply • BTA40-600B TRIAC Soft-Start • 9 Bands 160m–10m incl. WARC • …
Emtron DX-2V Linear Amplifier:Restoration & Service Guide GU84B (4CX2500A) Tetrode • 6‑Metre Specialist (50 MHz) • 2,000 W Output • Single‑Band 50 MHz Pi‑Network • Dedicated 50 MHz Plate Choke • Parasitic Suppression Critical • QSK Standard • Debut: Dayton Hamvention 2010 • Emona…
Emtron DX-3 Linear Amplifier:Restoration & Service Guide GU78B (4CX3000A) Tetrode • 3,000 W Carrier / 4,000 W PEP • 9 Bands 160m–10m incl. WARC • Dual-Fan Cooling • 700 µH Plate Choke • Horizontal AMPC Board • QSKv3 (Two Relay Options) • 60–90 W…
Emtron DX-3SP Linear Amplifier:Restoration & Service Guide Two FU-728F Tetrodes in Parallel • 4,000 W Carrier / 5,000 W PEP • 3,400 V DC Plate Supply • 9 Bands 160m–10m incl. WARC • Three Bias Pots (POT3 + POT10/BS1 + POT9/BS2) • Safety…
Emtron DX-4 Linear Amplifier:Restoration & Service Guide Two GU84B (4CX2500A) Tetrodes in Parallel • 4,000 W Carrier / 5,000 W PEP • 3,100 V DC Plate Supply • Separate Standalone HV Power Supply (3 Variants) • Three-Interlock Serial Safety Chain • Auxiliary Transformer in…
Henry Radio HF Linear Amplifiers:Omnibus Restoration & Service Guide All HF Tube & Solid-State Models • 2K/3K/4K/5K/8K Series • 1963–2005 • Los Angeles, California • Grounded-Grid Triodes • 3-400Z • 3-500Z • 8873/8874/8877 • 3CX1200A7/D7 • 3CX3000A7 • 5CX1500A •…
Heathkit SB-200 Linear Amplifier:Complete Restoration Guide Circuits • Cabinet • Safety • Component Replacement • Modern Upgrades • SB-201 Coverage 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 572B Triode — 600 W Class ⚠ High Voltage Equipment Abstract. The Heathkit…
Heathkit SB-220 Linear Amplifier:Complete Restoration Guide Circuits • Cabinet • Safety • Component Replacement • Modern Upgrades 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 2 kW Class — 3-500Z Triode ⚠ High Voltage Equipment Abstract. The Heathkit SB-220 is…
Community Join the Vintage AmateurRadio Restoration Group A dedicated mailing list for amateurs who restore, study, and operate vintage HF equipment — Collins, National, Hammarlund, Hallicrafters, Drake, Heathkit, and beyond. Technical advice, restoration notes, and a community that values doing…
Collins 180S-1 Jumper Plug Engineering Design | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Collins S-Line — Engineering Design Document Collins 180S-1Jumper Plug Reproduction A comprehensive engineering design for fabricating reproduction jumper plugs for the Collins 180S-1 antenna tuner — including circuit…
Collins 180S-1 Antenna Tuner Restoration Guide | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Collins S-Line Accessories Restoration Series Collins 180S-1Antenna Tuner Restoration Guide A complete field guide to the cosmetic and mechanical restoration of the Collins 180S-1 pi-network antenna tuner —…
R-390/URR Restoration Guide | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Collins Military Receiver Restoration Series R-390/URR ReceiverRestoration Guide A complete field guide to the cosmetic and mechanical restoration of the Collins R-390/URR military HF communications receiver — covering disassembly, the critical…
R-390A/URR Restoration Guide | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Collins Military Receiver Restoration Series R-390A/URR ReceiverRestoration Guide A complete field guide to the cosmetic restoration of the R-390A/URR military HF communications receiver — covering disassembly, haze gray finish specification, panel…
Hammarlund SP-600 Restoration Guide | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Boatanchor Receiver Restoration Series Hammarlund SP-600Restoration Guide A complete field guide to the cosmetic and mechanical restoration of the Hammarlund SP-600 series military HF communications receiver — covering variant identification,…
R-388/URR Restoration Guide | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Collins Military Receiver Restoration Series R-388/URR ReceiverRestoration Guide A complete field guide to the cosmetic and mechanical restoration of the Collins R-388/URR military HF communications receiver — covering disassembly, paint stripping,…
Collins S-Line Cabinet & Trim Restoration Guide | VK6ADA VK6ADA vk6ada.com.au • r-390a.net Collins S-Line Restoration Series Cabinet, Bezel & Trim Restorationfor the Collins S-Line A complete field guide to restoring Collins S-Line cabinets, front-panel bezels, and all associated trim…
If you own or are restoring a Hammarlund SP-600, one resource you need to know about is Perry Sandeen’s An Anthology of Technical References for the Hammarlund SP-600 and its Variants. This is a comprehensive compilation covering the SP-600 receiver family…
VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins Vintage Radio › Collins KWM-2 / KWM-2A Serial Number Guide Collins KWM-2 / KWM-2A — Serial Number & Production Guide VK6ADA Technical Reference · Collins Vintage Amateur…
VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins Vintage Radio › Collins KWM-1 / KWM-1A Serial Number Guide Collins KWM-1 / KWM-1A — Serial Number & Production Guide VK6ADA Technical Reference · Collins Vintage Amateur…
Collins 75S-3 / 75S-3B / 75S-3C Receiver Serial Number Guide – VK6ADA VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins S-Line › Collins 75S-3 / 75S-3B / 75S-3C Serial Number Guide Collins 75S-3 / 75S-3B…
Collins 75S-2 Receiver Serial Number Guide – VK6ADA VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins S-Line › Collins 75S-2 (RARE) › Serial Number Guide Collins 75S-2 — Serial Number & Production Guide VK6ADA Technical…
Collins 75S-1 Receiver Serial Number Guide – VK6ADA VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins S-Line › Collins 75S-1 Serial Number Guide Collins 75S-1 — Serial Number & Production Guide VK6ADA Technical Reference · …
Collins 32S-3 Transmitter Serial Number Guide – VK6ADA VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins S-Line › Collins 32S-3 Serial Number Guide Collins 32S-3 — Serial Number & Production Guide VK6ADA Technical Reference · …
Collins 32S-2 Transmitter Serial Number Guide – VK6ADA VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins S-Line › Collins 32S-2 Serial Number Guide Collins 32S-2 — Serial Number & Production Guide VK6ADA Technical Reference · …
Collins 32S-1 Transmitter Serial Number Guide – VK6ADA VK6ADA · Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins S-Line › Collins 32S-1 Serial Number Guide Collins 32S-1 — Serial Number & Production Guide VK6ADA Technical Reference · …
◆ VK6ADA · r-390a.net · Topic Index Hollow State NewsletterComplete Topic Index The Community Archive — Unlocked & Indexed Editor: Les Locklear • Gulfport, Mississippi • ~1993–2001 53Issues 7Yrs Run 30+Contributors 18Topic Cats The Hollow State Newsletter (HSN) was the…
SDR Resource Guide · vk6ada.com.au OpenWebRX+ · Primary Websites & Resources Web-based Software Defined Radio — The Enhanced Fork OpenWebRX+ is an enhanced community fork of the original OpenWebRX web-based software-defined radio application. It extends the upstream project with additional…
Bill Orr W6SAI — Amateur Radio Legend | VK6ADA VK6ADA · Boatanchor Legends Series Bill Orr W6SAI Engineer · Educator · Author · Amateur Radio Legend 1919 – 2001 | W2HCE / W6SAI | DXCC Honor Roll | OSCAR-1 Pioneer…
Collins 30L-1 Serial Number Guide – VK6ADA VK6ADA Mike Peace · Vintage Collins Radio · r-390a.net Home › Collins 30L-1 Amplifier › Serial Number Guide Collins 30L-1 — Serial Number & Production Guide VK6ADA Technical Reference · Collins S-Line Vintage…
Collins 51S-1 / 1A / 1F / 1AF / 1B — AM, CW & SSB Receiver A comprehensive engineering analysis of RFI mitigation strategies, ferrite core selection, noise reduction techniques, and signal-to-noise ratio improvements for the Collins 51S-1 series receivers.…
Technical Whitepaper · VK6ADA · r-390a.net Rebuilding & Upgrading the Collins S-Line70K-2 Permeability-Tuned Oscillator (PTO) Modern Component Substitution · RFI Mitigation · Ferrite Core Techniques · Signal-to-Noise Improvement 75S-1 75S-2 75S-3 75S-3B 75S-3C/m 32S-1 32S-2 32S-3 KWM-2 KWM-2A AUTHOR Mike…