For a majority of the current US Ham population, to that question we likely would hear a resounding NO. Most wouldn't even know what it is.
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A 3 to 6 MHz ARC-5, BC-454
My 40M ARC-5
Way before the US formally entered WWII there was a push to modernize our military communications hardware. The ARC-5 components were actually a system of small sized radios that covered a portion of the LF and HF bands (up to 9 MHz). Obviously, the intended use was in aircraft.
At this time the physical size of the ARC-5 radio sets were small in comparison to a SX-28 or HRO-5. The receiver portion of the system used 6 tubes and depending on the band used different IF frequencies. The BC-453 covered the LF band and had an IF of 85 kHz. The BC455 (6 to 9 MHz) had a higher IF in the MHz range.
The Transmitters were a bit physically bigger and had 4 tubes including a magic eye tube. The output stage used a pair of 1625's (12V version of the 807's) good for 100 watts on CW.
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Two seconds of thought should make clear that by choosing the variable IF a very stable LO could be built in a single conversion approach. The Receivers could receive AM and had a BFO for CW. The transmitters could do CW "as is" but there was an accessory Modulator Box (BC-696) needed for AM.
In normal operation in an Aircraft the ARC-5's operated from 28VDC using a strap on Dynamotor for the Plate and Screen voltage and the filaments were wired series parallel to operate from 28VDC -- aircraft power.
Post WWII the Receivers and Transmitters were highly prized by the ham community. In 1955, ten years after WWII, I bought a NIB BC-454 (3-6MHz covering 75/80M) for $3.50, and a purpose-built power supply (plug in for the Dynamotor) was another $7.50. So, for $11 I had a ham band receiver.
The units were built like a battleship with gear drives on the VFO's/LO's. The build included gluing down all VFO wiring using "Glyptal" so the was no component movement which would affect frequency. Surprisingly the dials were linear and repeatable!
[Glyptal has been used in ARC-5 radios primarily as an insulating and protective coating. It helps seal and protect electrical components from moisture, corrosion, and vibration, which is crucial for maintaining the reliability of these vintage military radios. Some enthusiasts and restorers use Glyptal to recoat transformers, coils, and chassis interiors to preserve their integrity and prevent electrical shorts. Courtesy of Microsoft copilot AI.]
The BC-453 (the LF variant) tuned at 455 kHz, suddenly became a very hot item. It was known as the Q5'er. The trick was to take an output from the IF of a commercial receiver at 455 kHz and feed that into the antenna of the BC-453. You now had a dual conversion receiver with a second IF at 85kHz and a very narrow bandwidth (Q5). A really enterprising conversion by two California hams made the BC-453 into a SSB Transceiver
A discussion of the ARC-5 system would not be complete without a mention of Tony Vitale, W2EWL who converted an ARC-5 Transmitter into a Phasing Transmitter in a seminal QST article entitled "Cheap and Easy SSB'. In the early days of SSB, Tony's rig was found in many Mobile SSB installations. Read about it here on N2CQR's blog.
My very 1st station was the BC-454 and a 6V6 built on a wooden chassis at 3709 kHz (then a valid Novice CW operating frequency). For a TR I used an "open" big old DPDT knife switch. More than once I got RF burns a result of touching the switch while I was still transmitting.
When I headed off to Penn State in 1959, my BC-454 was on the bookshelf along with the textbooks. It was a great way to keep a connection with hobby while I was away at school.
Et Al, the ARC-5 was a pretty rudimentary system and consider that they were mass produced, and their life expectancy was in terms of months not years. So not much in the way of frills.
For long haul communications in the Bombers, we would see the BC-348 or HRO for the receiver and of course the Collins ART-13 with autotune for the transmitter.
I have always had weird ideas about commercial or military radios. The 1625 transmitting tubes used in the ARC-5 were really cheap like 25 cents for a NIB and so there was much interest in building transmitters using these tubes.
One issue with the 1625 was that the Cathode was internally connected to one of the grids. Hams being hams simply sawed into the base of the tube and removed that connection. You ask why? The answer is SSB operation using the Cathode Driven (grounded grid) topology which wanted to see only the Cathode. A pair of 1625 suddenly was a 100-watt Linear Amp.
I went one step further and converted an ARC-5 Transmitter into a complete linear amp including building the power supply inside the case.
At the time I had a Yaesu FT-7 which is a QRP radio and with the ARC-5 Linear it was now an all band 100-watt Transceiver. When I sold the FT-7, the amp went with it. What a hoot.
So now you know a bit more about the ARC-5 radio system. Don't bother to look on eBay -- a decent ARC-5 is upwards of $200, and I paid $3.50 in 1955.
Finally, many conversions of the ARC-5 receivers involved rewiring the filaments for 12VAC. Actually, if you were the clever sort, you could have a twofer. If you purchased two 25.2 VAC Filament transformers one at 3 amps and another at 1 amp you had the makings of a complete power supply for the ARC-5.
Step one made the 3-amp version as the side connected to the mains. Off the secondary you would light the filaments as well as provide an input to the second 25.2 volt trans former. Essentially the secondary sides were connected back-to-back.
So now what was the primary on the 2nd transformer was now the secondary. That voltage was fed into a bridge rectifier and instantly about 160VDC for the plates and screens. Thus, a twofer with two transformers connected back-to-back.
Them that know can make it go.
73's
Pete N6QW