Drake · HF transceiver · 1976–1978
Drake TR-4CW
Drake's TR-4 line packed a whole SSB station into one small box, with the power supply in its own cabinet. The TR-4 replaced the TR-3 in 1967 with a solid-state VFO, and Wikipedia says the line ended with the TR-4C and its variants in 1978. The TR-4CW is a TR-4C with one addition, a 500 Hz crystal filter on the sideband switch for CW. Drake's supplement sheet says everything else is the same, down to the alignment. Three 6JB6 sweep tubes run 300 W PEP input on SSB, and two 8-pole crystal lattice filters pick the sideband. It covers 80 through 10 m, with crystals available for the rest of 10 m. WB4HFN's serial-number log shows TR-4CWs tagged from late 1976 and a TR-4CW/RIT version from August 1977. Plan on an AC-4 supply at home or a DC-4 in a car.
TR-4CWTR-4CW/RIT (logged from 1977)
Spec at a glance
- Maker
- Drake
- Type
- HF transceiver
- Launched
- 1976
- Made
- 1976–1978
- Covers
- 80 to 10 m: 3.5–4.1, 7.0–7.6, 13.9–14.5, 21.0–21.6 and 28.5–29.1 MHz; crystals for the rest of 10 m
- Modes
- LSB, USB, CW, AM
- Power
- 300 W PEP input SSB; 260 W input CW and AM
- Finals
- Three 6JB6 sweep tubes in parallel
- Receiver
- Under 0.5 µV for 10 dB S/N; 2.1 kHz SSB and 500 Hz CW crystal filters
- Power supply
- External: Drake AC-4 (120 V AC) or DC-4 (12 V DC)
- Weight
- 16 lb
- Also listed as
- TR4CW, TR-4Cw, TR 4CW, Drake TR4CW
Bench check
Power, receive, finals and supply
- Transmit power
- Drake rates it at 300 W PEP input on SSB and 260 W on CW and AM, and rigpix lists 150 W maximum output. Ask for a wattmeter reading into a dummy load on 80, 40, 20, 15 and 10 m. A later Drake sheet for FCC emission rules caps plate current at 350 mA on 80, 40 and 15 m, so lower output there can be by design.
- Receiver
- Drake rates the receiver at under 0.5 µV for 10 dB S/N, with a 2.1 kHz SSB filter. Ask for a video of it hearing stations on each band. The stock 10 m segment is 28.5 to 29.1 MHz, and other parts of 10 m need accessory crystals, so a silent 28.0 MHz isn't a fault.
- Finals
- Three 6JB6 sweep tubes in parallel. Drake says to replace them as a matched set of the same brand, and to realign and re-neutralize if the brand changes. The manual warns that holding plate current above 0.1 A for more than 6 seconds while untuned ruins them fast, and says the pi-network wants an SWR under 2:1, lower on 80 m.
- Power supply
- There's no supply inside. At home it needs a Drake AC-4 on 120 V AC, which Drake designed to fit inside the MS-4 speaker, and in a car it needs a DC-4. A listing without either isn't ready to switch on. WA8SAJ notes later AC-4s used a 6 A slow-blow fuse and a 3-wire cord.
- Dial and display
- The VFO is a permeability-tuned oscillator read on a dial of two transparent discs, and Drake rates drift under 100 Hz after warm-up. Lamps show the sideband in use and when the VFO is running. If tuning feels stiff, WB0IQK's Drake PTO notes start with cleaning dried lubricant off the screw drive.
- Filters and options
- The 500 Hz CW filter is what makes it a CW, selected by a third position on the sideband switch, so look for it in the front-panel photos. Options included the 34-PNB noise blanker, RV-4C remote VFO, FF-1 fixed-frequency adapter and MS-4 speaker. A TR-4CW/RIT version, logged from 1977, adds RIT.
Should come with it
- A Drake AC-4 supply (or DC-4 for mobile) and its cable
- An MS-4 speaker, which can house the AC-4
- The TR-4C manual with the TR-4CW supplement sheet
- A high-impedance microphone
Check the listing photos against this list, and ask the seller about anything you can’t see. A missing piece should come off the price.
What to check
WB0IQK's notes on WB4HFN say a misbehaving TR-4 antenna relay should be cleaned first. Drake's manual warns that long tune-ups at high plate current wear out the 6JB6 finals, so ask how it's been tuned. The AC-4's old filter capacitors are the usual rebuild, and WA8SAJ reports doing about 500 of them.
- 01Power out: Ask for wattmeter readings into a dummy load on all five bands. Steady output on SSB and CW is what you want, not a radio that only lights up.
- 02Every band: Ask for a video of it hearing stations on 80, 40, 20, 15 and 10 m. Each band should come alive when the band switch moves.
- 03Finals: Ask how old the 6JB6 finals are and whether they're a matched set. A matched set, neutralized after any swap, is what you want.
- 04CW filter: Check the front-panel photos for the 500 Hz position on the sideband switch. That position is what separates a TR-4CW from a plain TR-4C.
- 05Power supply: Check the listing includes an AC-4 or DC-4 and its cable. Without one it can't be powered at all.
- 06Relay: Ask whether it switches cleanly between receive and transmit. A relay that chatters or drops out needs its contacts cleaned.
- 07Tuning: Ask whether the VFO turns smoothly across the dial. Stiff or jerky tuning means the PTO needs cleaning.
- 08Mic and manual: Ask which mic comes with it and whether the manual is included. Drake specified a high-impedance mic, so plan on one if none is listed.
- 09Model version: Read the badge in the photos for TR-4CW or TR-4CW/RIT. A plain TR-4C has no CW filter.
New to used rigs? How to check a used ham radio covers power out, receive, the finals and the display, and buying vintage tube gear covers old capacitors, tubes and first power-up.
Find one on eBay
We haven’t been through this model’s listings yet. Search eBay and run every listing through the checklist above. Ask for a wattmeter reading into a dummy load on a few bands (powering on proves nothing about the transmitter), whether it hears signals on every band, and what filters and options are installed. Pass on any seller who won’t answer.
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