Investigating the XB-70 cockpit equipment, I notice that it only had (two) UHF radios, of the AN/ARC-50 model, for the 225–399.95 MHz band. No VHF radio that could be used to talk to civilian ATC or civilian aircraft. Is that correct? Was that normal in those days?
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$\begingroup$ Based on aviationtoday.com/2005/02/01/militarycivil-interoperability , it does seem that interoperability with civilian radios was not a priority. Presumably not at all for an aircraft of which only two prototypes were built that were used as experimental aircraft and had a rather short time in service, and never left the US. $\endgroup$– tmlCommented Feb 10, 2022 at 21:47
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4$\begingroup$ Back in the sixties as it is today, most civilian ATC facilities have UHF frequencies available. $\endgroup$– user22445Commented Feb 10, 2022 at 23:30
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$\begingroup$ A related question is when did the military start using UHF radios? Were WWII aircraft all generally equipped with only UHF? $\endgroup$– Charles BretanaCommented Oct 12, 2022 at 13:51
4 Answers
I can answer for the USAF. In the early 70s, The T-37 and the T-38, (Undergraduate Pilot Training aircraft), did not have VHF, only UHF, and the F-4C/D/E had only UHF.
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$\begingroup$ Same for USMC and USN in the 80s, 90s, and 00s. $\endgroup$ Commented Feb 11, 2022 at 4:50
The RAF Dominie, from the sixties, had a single-channel VHF radio, a single-channel UHF radio, a single-channel HF, and some listen-only capability on the nav radios. And they could, of course, observe signal lamps.
Actually, that's slightly unfair. The UHF set could monitor Guard and also the selected channel at the same time.
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$\begingroup$ The Dominie was a version of the Hawker Siddeley (later BAe) 125 biz-jet, made for the RAF as an advanced navigation trainer. $\endgroup$ Commented Feb 11, 2022 at 14:44
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$\begingroup$ Yep, and the equipment fitted to it was completely different to the civilian HS.125 $\endgroup$ Commented Feb 11, 2022 at 14:48
Most of the military aircraft that I flew ( Jet Provost, Hunter, Phantom, Vulcan etc)in the 70’s only had UHF radios, usually an ARC 52 box. There was no requirement for VHF, the UK had total UHF military ATC coverage as did anywhere else that we were liable to take the aircraft. You have to bear in mind that airways flying would only have been done by air transport type aircraft which would have had VHF fitted for that purpose.
Typically, yes that’s true, most military are craft only had UHF radios aboared. This is not a problem for comms with ATC in the NAS, since they operate on UHF frequencies as well. It would make it difficult to communicate by radio with civilian airplanes.