A Pair of Vintage HF Stations
Including
Comments on Vintage Station Setup
K4MSG - Paul Bock of Hamilton, Virginia
Reported and photographed by Paul Bock - K4MSG
December 7, 2007

        In previous articles for the LARG Internet Site I admitted being bitten by the urge to assemble a vintage amateur radio station. "Vintage" is generally taken to mean a station consisting of equipment designed around vacuum tube technology as opposed to being designed around transistors, integrated circuits, etc. There are problems with assembling such a station, not the least of which is that vacuum tubes are becoming more difficult to find and significantly more expensive (I'll touch on this later). Notwithstanding the problems, a fair number of amateurs - myself included - have a love affair with this "old technology" and so embark on a vintage station project.

        One of the most fascinating things about vintage equipment is that to us "old-timers" most of it "looks like" radio equipment is "supposed" to look. I realize that this is a matter of generational perspective and it's not a really strong argument for sinking centabucks or kilobucks into something that's fifty years old (and sometimes much older), but there is a definite mindset as illustrated in the following personal story.

        Back in the mid-1970s I was helping avid fellow VHFer Bill Shaw, WA4MMP (SK), align his Clegg Venus 6-meter transceiver, a 40-watt masterpiece of SSB/CW tube technology sporting an Eddystone dial on the front panel. After we finished the alignment - the Venus was still out of its cabinet and sitting on its side, the meticulously hand-wired chassis and vacuum tubes plainly visible - I noticed a Drake TR-22, a very compact, solid-state 2-meter FM rig. When I commented on it Bill replied, "Yep, it's a great little rig, very convenient for me to carry in the car, a wonderful communications package.. I suppose that it's the way of the future, but to me THIS" - and he pointed to the Venus - "THIS is a RADIO!"

        Currently I have a dual-position vintage HF station as shown in the photo. The left half is 1950s-60s technology with a Johnson Viking Adventurer 50w CW transmitter, Johnson Viking 122 VFO, and Drake R-4A receiver & MS-4 speaker. The right half, 1960s-70s technology, is a Drake "4B line" consisting of an R-4B receiver, T-4XB CW/SSB/AM transmitter, MS-4 speaker and AC-4 power supply. Each station has its own key & bug and the right-hand station includes a vintage D104 microphone and modern antenna coupler for matching the T-4XB. There are some unique requirements as described in more detail below.

K4MSG's Dual HF Vintage Stations

        As noted in a previous article, I assembled a vintage station several months ago consisting of a Johnson Viking Adventurer transmitter (80, 40, 20, 15 & 10 meters) with a Johnson Viking 122 VFO and a Drake R-4A receiver including matching MS-4 speaker. This station forms the left half of the dual vintage station.

        The original VFO was replaced with an identical one that is nicer cosmetically even though functionally there is no difference. This station requires manual switching of the antenna between the receiver and transmitter as well as a couple of other switching functions and I built a simple relay box to take care of these needs. The box is mounted on the left side of the shelf as shown in the photo.

        The key and bug for this station are U.S. Army Signal Corps models, a J-38 straight key and Lionel J-36 "bug," the latter being a clone of the Vibroplex J-36 and Lightning Bug and dating from about 1944.  

J-38 Key & Lionel J-36 Bug

        This key & bug combination was common in the 1950s since a lot of WWII and Korean War surplus military equipment was still available at very cheap prices. The J-38 was my first key, a Christmas gift in 1955. 

1950s-60s Vintage 80-10m CW Station

        The use of a Drake R-4A receiver with this station is arguably mixing oranges with apples since it dates from 1967 whereas the Adventurer & VFO date from the late 1950s. However, performance won out over historical accuracy since the R-4A is a better receiver than most 1950s units.

        Note that there is no external antenna coupler. The Adventurer has a pi-network output circuit that can match a wide range of antenna impedances, typically 30 ohms to several hundred or even close to 1000 ohms. This means that the Adventurer, like most transmitters of its day, can tune dipoles, end-fed random wires and almost anything else.

        For some time I had harbored a desire for a Drake 4-line and as luck would have it I chanced upon an excellent deal for a 4B-line. Up until about a year ago this equipment had been owned by the same ham since new. The second owner was "underwhelmed" with it and sold it to me at a very good price. It consists of an R-4B receiver, T-4XB transmitter, MS-4 speaker and AC-4 power supply for the T-4XB (mounted inside the MS-4). Frequency coverage is 160, 80, 40, 20, 15 & 10 meters on CW, SSB and AM modes. Everything is in near-mint condition and works perfectly.

1960s-70s Vintage
160-10m CW/SSB/AM Station

        I added an MFJ-971 antenna coupler with homebrew antenna switch & MFJ dummy load as shown on the top shelf in the photo. Like modern solid-state equipment (and unlike the Viking Adventurer) the Drake T-4XB is designed to match a 50 to 75-ohm load and must first be tuned into a dummy load on the band of interest. The antenna switch is used to connect the transmitter first to the dummy load and then to the antenna with the MFJ tuner providing the necessary match to the latter.



        Tuning up the T-4XB is not unlike tuning up the Adventurer except that it is more involved and requires more steps. Modern hams who are used to today's broad-band radios that require no transmitter tuning, just antenna matching (and not even that with a modern auto-tuner), might well become frustrated with tune-up of a vintage transmitter like the T-4XB but that was the modus operandi of a lot of older radio equipment and illustrates one of the differences between "then and now."

       Since the T-4XB operates SSB & AM as well as CW I picked up a D104 microphone with the amplified T-UG8 grip-to-talk stand. It could be used with a modern transceiver were it not for the impedance mismatch, i.e., the D104 is a crystal microphone and high-Z (NOTE: Heil offers a replacement Heil element kit for the D104 that includes an impedance-matching transformer to allow its use with modern and vintage rigs).

       In a desire for period accuracy I used a chrome-plated Johnson Speed-X straight key from the 1960s and a Vibroplex "Blue Racer Standard" bug that was built in 1967 (one of the last of this model). Neither key has a shorting switch but the T-4XB has a "TUNE" position so this isn't a problem. A 1960s Telephonics headset completes the equipment.

1960s Speed-X Key &
Vibroplex Blue Racer Bug

       Although the Drake equipment pre-dates the 1979 establishment of the WARC bands on 30, 16 and 12m, both the receiver and transmitter provide the capability to operate on other 500 kHz portions of the HF spectrum between 1.5 and 30 MHz (except for 5-6 MHz) by using accessory band-set crystals. Ten (10) such crystals may be used in the R-4 series receivers and four (4) in the T-4 series transmitters. (NOTE: Although the receiver & transmitter have 1.5-3 MHz positions - i.e., 160m - on their bandswitch indicators, an accessory crystal is required for operation on this band. The same is true if one desires to cover more than 500 kHz of the 10m band. Crystals can be obtained from International Crystal Mfg.). The receiver and transmitter may be operated with the two units tuned separately by their respective PTOs, both tuned with the receiver PTO, or both tuned with the transmitter PTO. This allows transceive or split-frequency use for working DX.

       How does the equipment perform? Quite well given its age, although there are differences when compared to modern equipment, to wit:

              1. Keying of the Adventurer isn't always perfectly clean and chirp-free and sometimes the oscillator tuning has to be "tweaked" for best CW note. The VFO can be keyed on 80 meters fairly cleanly, but on 40 meters and higher bands it is best to let the VFO run continuously when in transmit mode and just key the Adventurer. The homebrew relay box I built provides the necessary controls for these different types of operation.

              2. The Adventurer/R-4A station requires manually flipping a switch on the homebrew relay box to go from receive to transmit and back, so break-in operation on CW is not possible. The difficulty this creates is that if you are slow on the switch (and sometimes even if you're pretty fast) you'll miss the first character or two sent by the other station, who is usually someone running a modern rig set up for fast semi break-in or full break-in.

              3. The Drake T-4XB does antenna switching automatically and has adjustable time delay on keying, so fast semi break-in operation is possible although not as fast as a modern radio. It provides receiver muting, a CW sidetone and PTT or VOX operation on SSB & AM.

              4. The T-4XB must have the driver & final amplifier tuning touched up if the frequency is changed more than about 25 kHz.

CLOSING COMMENTS

       While most vintage radios can be made to operate at their original level of performance there are some caveats. First, the "original level of performance" may not meet modern technical standards, so be careful. Chirps or clicks on your CW signal may net you an OO report or FCC Advisory Notice although one way to mitigate this is to stick to the generally-accepted "boatanchor" CW frequencies where the regulators tend to cut a little slack. Fortunately, the Drake T-4XB generally meets modern standards even if the Adventurer may not always do so.

       As far as parts replacement, the biggest problems with all vintage radio equipment are the electrolytic capacitors and, to a lesser extent, the so-called "paper" capacitors (foil separated by waxed paper). Over time they dry out or otherwise deteriorate and eventually fail, sometimes with devastating consequences to irreplaceable parts like power transformers. "Re-capping" has therefore become a way of life for vintage equipment owners. In my case the R-4A and Adventurer have been re-capped but the R-4B, T-4XB and AC-4 have not, so upgrading the 4B-line is definitely in the plan (the Viking VFO has no electrolytic or paper capacitors).

       I mentioned the cost of tubes and here are some examples based on current prices from Antique Electronic Supply.

              Adventurer: 807 amplifier tube: new, $20; used, $10. 5U4G/5AS4 rectifier tube: new, $30; used, $16. 6AG7 oscillator tube: new, $6

              Drake T-4XB: Most expensive are the 6JB6A power output tubes at $27 apiece. There are two and they should be bought as a matched set which adds $2 per tube to the cost. Used ones are $13 but not recommended.

              Drake R-4A & R-4B: Most expensive is the 12AX7A at $25 new or $13 used. Other tubes range in price from $4.00 to $13.00 per tube. A full complement of new tubes for a later version R-4A (11 tubes) currently runs about $110.00.

       Despite the shortcomings of older parts requiring replacement, tube prices, and questionable conformity to modern technical emission standards, repairing and using vintage vacuum-tube equipment can be an enjoyable pastime. It really is a step back in time.