Mass production was key to survival during the Second World War. So much stuff was made that there continues to be volumes of new unpacked stuff left over and tons of used equipment for sale at reasonable prices. Availability of this war surplus provided experimenters in the mid 20th century with access to high performance test equipment, radio equipment, and high quality components for the first time.
Even today this old stuff continues to motivate and inspire the young generations because of its high build quality, unique electro-mechanical approaches, and overall innovative designs which continue to be relevant into the 21st century. In this post we will show you how to get started in the hobby of resurrecting WW2 radio equipment and putting it back on the air.
The ARC-5, Your First Receiver
Many amateur radio operators became interested in the hobby after being given an old ARC-5 ‘command set’ receiver. These radios were typically used for communication between aircraft within a formation, hence the name ‘command set’. There are many different receivers and transmitters within this line covering frequency bands from 190 KHz to 146 MHz, most of which are capable of tuning in AM, CW, and SSB (by adjusting the BFO).
I recently purchased the receiver shown above at a military antique store in Lake George, NY. This radio was interesting for two reasons, it was completely original and never modified for amateur use (over the years amateur radio operates hack these radios to suite their needs at the time), and it had a build date of Feb 1942.
Rather than replacing all of the old capacitors as is usually required when restoring antique radio gear, I tested each and every one of them and only replaced the bad ones. Of those that I replaced, I re-stuffed the original cans that held the old capacitors so that it did not look like anything had been changed.
I also restored the old Dynamotor, which is a unique motor-generator device used during the second world war to generate high plate-voltage from the 28 VDC aircraft bus. These radios make for a great first-WW2 radio restoration because they are simple, extensive documentation exists, and you can buy an ARC-5 receiver at just about any hamfest for less than $50, or in my experience they are often given away to anyone who shows genuine interest.
Robotic Radio Equipment and Servo Control
Once you’ve cut your teeth on a command set it is time to step up into the big leagues. Dhalgreen440 shows us some very impressive restorations of WW2 radio gear including many of the auto-tune systems, where servo motors would automatically tune the transmitter or receiver (or both) to pre-set channels at the flip of a switch, like this ARC-1:
Here is an ARN-7 automatic radio direction finding set, that uses servo motors to lock-into AM broadcast (or other medium wave) stations, providing a real-time compass bearing to that station for the purposes of airborne radio navigation:
Ever wonder what it would be like to talk to your friends on a tank radio? Check out this demo of an SCR-508:
Just Turn the Crank
In addition to this impressive equipment there are many pieces that will simply just work right out of the box without the need for any restoration such as this BC-778-D emergency beacon. All you have to do is turn the crank and it will start transmitting an SOS automatically in Morse code (or the letter A for test purposes) at 500 KHz:
The Beginning of a Legend, Collins Radio and the ART-13
And of course lets not forget the legendary Collins ART-13 with auto-tune. The ART-13 is one of the most popular WW2 high frequency radio transmitters that you will hear on the air. Collins Radio was the first to commercialize auto tune-radio technology in the 1930’s, combining artful mechanical design with high performance radio receiver technology:
And there are many more examples of radio enthusiasts bringing back to life WW2 radio equipment. This technical community mostly revolves around the magazine Electric Radio and their work is proudly shown on YouTube.
You Can Do It!
So pick up some surplus WW2 radio gear next time you see it and press it back into service. It will be an intellectual adventure where you will learn about history, RF design, and servo-mechanisms along the way. (Each piece Gregory L. Charvat’s WW2 radio collection is fully operational and on the air.)