lg opine logo     Updated 26 September 2001       URL is http://our.tentativetimes.net/opine/surplus.html

Here is W9PPG's column on using surplus radio equipment. Article ©1998 Wm. J. Weinhardt, write for permission to reprint! Email wswart@parlorcity.com

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RADIO SURPLUS, BACK IN THE EARLY 1950'S

In the early 1950's there was a large quantity of World War II surplus equipment still available at bargain prices from a multitude of surplus equipment dealers.

The most popular and most numerous of the surplus equipment was the ARC-5 Command set series of transmitters and receivers. For their day these were small, well-engineered pieces of equipment which were used on military aircraft during the war. Hams quickly found that they were easy to modify and use as ham equipment. The equipment had originally been designed by Aircraft Radio Corporation but during the war years was also produced in large numbers by the Western Electric division of ATT and Colonial Radio Corporation.

The transmitters used a 1626 triode as the vfo with a pair of 1625's (12 volt version of the 807) in parallel as the final amplifier. There was also a modulator using a pair of 1625's on a separate chassis. There were five transmitters covering different frequency segments as follows:

2.1 - 3.0 MHz, 3.0 - 4.0 MHz, 4 -5.3 MHz, 5.3 - 7.0 MHz, and 7.0 -9.1 MHz.
There were two of these that hams immediately found could be put on the ham bands. These were the ones whose frequency range covered the 80 or 40 meter ham bands. The 2.1 -3.0 MHz transmitter could without too much difficulty be retuned to cover the 160 meter ham band. During the late 40's and early 50's, there were large numbers of these transmitters in use by amateurs. The 4.0 - 5.3 MHz and 5.3 - 7.0 MHz transmitters were kind of outcasts and many of these were dismantled for parts for other building projects.

Then in the early 1950's single side band began to gain popularity in ham radio. Much of the early ssb was generated at an RF frequency of 9.0 MHz. Hams soon found that the two aforementioned transmitters with slight modification made great 5.0 - 5.5 MHz vfo's for mixing with the 9.0 MHz ssb signal to put them in either the 80 or 20 meter bands depending on whether the next stage was tuned for the sum or the difference mixing product. The ham radio magazines often had articles about conversion and modification of these radios to various ham bands.

There were five main receivers in the series covering the following frequency ranges:
190 - 550 Khz, .52 - 1.5 MHz, 1.5 - 3.0 MHz, 3.0 - 6.0 MHz, and 6.0 - 9.1 MHz.
It is my understanding that there were small numbers of higher frequency range units manufactured at least experimentally but I myself have not seen any. These receivers were 6 tube superhets with one RF amplifier, mixer/oscillator, two if amplifiers, detector/bfo, and audio amplifier. Like the transmitters, they had tubes with 12volt filaments but wired in series so that they could operate the filaments directly from the aircraft 24volt dc system. For high voltage they used a 24volt dynamotor mounted on the rear of the chassis. The dynamotor provided approximately 180volts dc for the high voltage.

The most popular receivers were the two that covered the 80 and 40 meter amateur bands. It was soon found by amateurs that the 190 - 550Khz receiver was of great use to improve the selectivity of many commercial and home brew amateur receivers then in use. Most of the commercially available ham receivers of the day had 455Khz if amplifiers and most lacked selectivity on crowded ham bands. The if frequency of the 190 - 550Khz command set was 85Khz and had far better selectivity.

After conversion to AC power and the addition of a switch for the BFO, it was a simple matter to couple the antenna input of the command receiver to the output of the last if stage of the ham receiver. With the command set then tuned to 455Khz, the ham now had a very selective receiver. Since these radios were available often for $5.00 or less, it was not terribly expensive even considering that an AC power supply had to be provided.

My first station as a ham used a BC-454 3.0 - 6.0Mhz Command set as receiver back in 1951. This got me on the air on the 80 meter novice band and I made many contacts with it. Many hams used this receiver with converters in front of it to cover the higher frequency ham bands including 6 meters and 2 meters. While it lacked selectivity, it certainly was an inexpensive way to get started.

Both the transmitters and receivers turned out to be valuable sources for parts for other building projects. QST and CQ magazines of this era had articles every month or two of conversions and modifications of these radios or building projects which used these as a source of parts. There was a phasing type SSB exciter which used either the 4.0 - 5.3 or the 5.3 - 7.0 MHz transmitter as its basis. The roller inductors and variable capacitors from the transmitters found use as components for building many different transmitters and antenna matching units.

Two other very popular receivers that were available in fairly large numbers were the BC-348 and the BC-342 series with their various subdesignations. The BC-348 covered 1.5 to 18.0Mhz and had a 200 -500Khz range as well. I used a BC-224 (a version of the BC-348) for a period of time in the mid 50's. While I am not personally familiar with the BC-342 I know it covered 1.5 - 18.0Mhz but I don't know if it had a low frequency range. For 10 and 15 meter coverage, a converter could easily be added to convert the 10 or 15 meter signal to one of the BC-348 or BC-342 tuning ranges. These made far better ham receivers than the command set series and they had the advantage that they would cover several of amateur bands.

For the VHF enthusiast, there was the SCR-522 transmitter and receiver. These were rather easily converted to 2 meter am operation and there many of these in use. As 2 meter fm was more popular in the Lafayette area, I was more into conversion of some of the early commercial VHF hi-band equipment to the 2-meter band so I never became familiar with this line of military surplus.

While there was certainly other WWII surplus equipment that found its way into ham usage, I have discussed what was the most numerous and popular. I am currently restoring a BC-348 and a complete line of the command set series of transmitters and receivers. Occasionally, this equipment can still be found at hamfests.

Some of the surplus gear available wound up being mainly a source of parts. A prime example of this was the BC191/375 transmitter with its associated tuning units. This GE built gear was a dinosaur of a radio and was replaced by the ARC-5 series. Few of these were put on the air by hams but many were dismantled for the parts they contained. The tubes in these weren't of much use since they were pretty much obsolete, a number 10 oscillator and 211 triodes for the amplifiers and modulators. I think it might be interesting though to build a 160 meter CW transmitter using 211's as the amplifier....should be a real shack warmer. These units were a real treasure trove of parts. The variable capacitors, high voltage micas, meters, ceramic multi-position switches, ceramic coil forms, etc. were used in many building project of the day. Poking around the boxes under tables at hamffests I still frequently recognize parts that probably came from one of these monsters.

I eventually will have a station back on the air using some of this restored WWII equipment.

73's...W9PPG

article ©1996 William Weinhardt, email me for permission to use

W9PPG, Bill Weinhardt's Radio Columns
1. Why use CW?
2. Learning Morse Code
(the easier way)
3. Great Fun
with CW

4. Antenna Ideas
5. Old Equipment
I've bought and made
6. More Radio Nostalgia
7. W9ASX, My Elmer, Glen Rogers
8. Surplus Equipment
9.Questions from my e-mail, with answers
10. Antenna design; then Indiana's Historic Radio Museum
Science Fair Project, Keyer
Who saved my life?
All columns ©copyright Bill Weinhardt 1996-1999

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