[ARC5] 1960s-1970s US Army Aircraft Radio

[Mike Morrow]

Jeep wrote:

> I note that a number of US military aircraft (fixed and rotary wing)
> have both VHF and UHF, these days.

True, but not at all new.  Almost every US Army aircraft in the 1960s
and later carried:

VHF-FM ("1" on C-1611*/AIC interphone),
UHF-AM ("2" on C-1611*/AIC interphone),
VHF-AM ("3" on C-1611*/AIC interphone),
HF-USB ("4" on C-1611*/AIC interphone, ONLY those few A/C with HF-SSB)

In that era, in US Army aircraft:
 
VHF-FM was provided mainly by AN/ARC-54, AN/ARC-131, or AN/ARC-114*,
UHF-AM was provided mainly by AN/ARC-55, AN/ARC-51BX, or AN/ARC-116*,
VHF-AM was provided mainly by AN/ARC-73, AN/ARC-134, or AN/ARC-115*,
HF-USB was provided by AN/ARC-102.

It's amazing the amount of radio gear carried on every UH-1 in Vietnam.
Even the tight-for-space AH-1G Cobra carried VHF-AM, in addition to the
essential VHF-FM and UHF-FM.  Its control panel was in the front with
the pilot-gunner.  It provided an additional coordination link with
aircraft they were supporting.

I have UH-1/CH-47/AH-1 Army helicopter pilot friends who report effects
that surprised them when using their tactical VHF-FM (30 to 76 MHz)
sets in Vietnam in the late 1960s...like getting a response from an
Army unit in South Korea or the Philippines instead of local in
South Vietnam.  Many of us will remember the peak in solar activity
in the late 1960s for Cycle 20 and its effects on propagation in the
frequency ranges used by tactical VHF-FM sets. 

Mike / KK5F