AN/ARC-5
It is described as "a complete multi-channel radio transmitting and receiving set providing communication and navigation facilities for aircraft.
The LF-MF-HF components are designed to transmit and receive voice, tone-modulated, and continuous wave (cw) signals.
"[1]: 1 Its flexible design provided AM radiotelephone voice communication and Modulated continuous wave (MCW) and Continuous wave (CW) Morse code modes, all of which are typical capabilities in other Navy aircraft communication sets of the period.
[1] The AN/ARC-5 command set was used by the US Navy from the latter part of World War II into the post-war era.
The designations ARA and ATA are a pre-World War II Navy equipment nomenclature.
Structurally and in appearance, they were virtually identical except for most later units being left unpainted aluminum in contrast to the black wrinkle finish of the Navy sets.
In late 1943, the U.S. Navy fielded an improved and more flexible set of its ARA/ATA radios under the new Joint Army-Navy (JAN) nomenclature of AN/ARC-5.
The latter allows a check of the dial calibration by giving a visual indication, viewable by raising a small cover, when the oscillator's frequency matches that of an internal crystal.
Electrically, AN/ARC-5 transmitters use high-level final amplifier plate modulation, and the output tank circuit is shunt high voltage fed.
The two earlier systems use less effective screen modulation, and the output circuit is series high voltage fed.
Unlike earlier systems, none of the AN/ARC-5 control boxes have audio jacks for the microphone, headphone, or key.
The output is sent to the broadcast band receiver tuned to the modulating frequency to further demodulate the carrier for voice messages or for a Morse code letter indicating to the pilot his bearing from the homing transmitter.
Western Electric developed a four-channel crystal-controlled VHF-AM receiver and transmitter for the U.S. Army's SCR-274-N system.
AN/ARC-5 navigation receivers are not so stabilized, and if installed in the rack a control that allows remote tuning is required.
During World War II, the Navy began a slow movement toward VHF-AM for command functions in theaters where it made sense, beginning with the Western Electric WE-233A commercial airline set which was later re-designated the AN/ARC-4.
This experimentation even caused them to contract for and officially nomenclature a continuously tunable AN/ARC-5 VHF capability from Aircraft Radio Corporation for evaluation purposes, shown in the above chart, but by that time (latter part of 1944) channelized equipment became the preferred technology to reduce aircrew "fiddling" with controls, so it was not pursued beyond the evaluation quantities.
By late war, the discovery of "ducting" in the lower VHF band (that allowed Japanese tactical radio intercepts over long distances under certain conditions) drove development of the AN/ARC-12 (UHF version of the AN/ARC-1) and AN/ARC-27 sets in currently-used UHF-AM military aircraft band.
However, it is important to understand that this gradual movement to VHF was not accomplished overnight, and there were still pockets of documented HF command set employment through war's end, especially in smaller aircraft.
In terms of longevity, the AN/ARR-2 continued into service well into the 1950s, and the beacon band R-23A/ARC-5 receiver was still to be found in some older US Navy aircraft as late as the 1970s.
After World War II, surplus HF receivers and transmitters of the AN/ARC-5 family were extensively used in amateur radio stations.
Green's magazine alone published some 47 articles on converting command sets to amateur use over the following 10 years, reprinting them in a compendium in 1957.[3]: pp.
[4] The T-16 and T-17 transmitters which operated in the standard broadcast band were very hard to find on the surplus market but were used by some as low power "pirate" AM stations with the addition of a modulation transformer in the B+ line and a suitable audio amplifier which was a 50 watt PA, guitar, or 'HI-FI home entertainment amplifier.
The tuning system would allow the rig to be loaded into almost any kind of vertical or dipole antenna for neighborhood and beyond AM broadcasting.
