[Milsurplus] The AN/ARC-65 (and AN/ARC-58)

[David Ross]

Mike & the gang -

   As far as I can tell, the only difference between the T-605/ARC-58 
and the T-730/TRC-75 is that the TRC-75 unit has a jumper across the 
baroswitch (the baroswitch prevents the ARC-58 unit from keying if local 
air pressure is less than a certain minimum).
   My guess is that this was done to prevent the ground-based TRC-75 
from unkeying due to rapid local changes is air pressure (explosions, 
artillery concussion, etc.).

   Mike mentions 'parallel multiple receiver circuits' in the ARC-58 
coupler.  Actually these are in the ARC-58's antenna coupler control 
unit, and amount to up to three cascaded receive multicouplers.  The 
multicouplers fit inside the antenna coupler control unit and come in 
two flavors -  one for HF only and another for HF & LORAN use.  I don't 
know for sure what (if any) AUX HF receiver was used with the ARC-58 - 
maybe an R-648/ARR-41?

   Yes, the ARC-58 components also show up in the TSC-15 "Communications 
Central" radio shelter.  The TSC-15 contains the TRC-75 black boxes with 
a second TRC-75 receiver/exciter used as the full-duplex receiver.  Also 
in the 6' long TSC-15 shelter are a five-line telephone switchboard, a 
five line teletype switchboard, a four-channel teletype mux & 850 shift 
TTY modem setup (TGA-1), a MITE teletype, and various test equipment.

   There is another ground radio, similar to the TRC-75 but one 
generation newer.  It sits across the back of a jeep just like the 
TRC-75 does -  it is a full-duplex radio, has a 618T-3 for receive & a 
618T-3 radio for transmit and yet another 618T-3 radio as an unpowered 
spare.
   The Cold War was a great time to own stock in the Collins Radio Company.

73
Dave Ross    N7EPI



Mike Morrow wrote:
>> Does the TRC-75 relate to the ARC-65?
> 
> The AN/TRC-75 is a modification of the Collins AN/ARC-58.
> 
> It is a US Marine Corps ground set that used the same receiver-exciter R-761/ARC-58, but used an amplifier-power supply unit T-730/TRC-75 instead of the T-605/ARC-58.  Also, I believe the coupler CU-749/TRC-75 varied from the ARC-58 version in not having the parallel multiple receiver circuits, and the C-3141/TRC-75 control box had control label letters in a circle in addition to the normal labeling found on the ARC-58 version.  There were other differences too, plus the large amount of 115 vac 400 cps power that the AN/TRC-75 needed could be supplied from 28 vdc through a large inverter unit, while the AN/ARC-58 expected to get its ac power from the aircraft directly.
> 
> There are details of the TRC-75, as part of the Vietnam-era AN/TSC-15, at:
> 
> http://www.hypertools.com/tsc15.html
> 
> I think the Collins AN/ARC-58 pretty much eventually won out over the RCA AN/ARC-65 in USAF service.  I know, from having visited the avionics repair shops many times, that the B-52 and KC-135 aircraft at Blytheville AFB were all using the AN/ARC-58 in the late 1960s.  The total AN/ARC-58 installation was much lighter and had significantly higher power output (1000 watts vs. 400 watts) than that of the AN/ARC-65.  I've read somewhere that an AN/ARC-58 installation cost more than $20,000 in mid-1960 dollars, or more than $100,000 in today's cost.  To think I got my T-761/ARC-58 and T-605A/ARC-58 for $100 total!  This system is difficult to locate all the necessary items, so I look upon my AN/ARC-58 gear as the ultimate USAF cold war radio relics.  Forty years ago, when looking at the units at BAFB, I never dreamed I'd be able to get ahold of this type of gear.
> 
> 73,
> Mike / KK5F  
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