Guard Channels (was [Milsurplus] RE: Nutso (RE: WW2 B-29 VHF radio?)

Tue, 5 Feb 2002 08:44:22 -0800

----- Original Message -----
From: "ROBERT W. DOWNS" <[email protected]>
To: "milsurplus" <[email protected]>
Sent: Tuesday, February 05, 2002 5:41 AM
Subject: Re: Guard Channels (was [Milsurplus] RE: Nutso (RE: WW2 B-29 VHF
radio?)

Hi,

I'm Rian and have worked on ARC-1s in the Navy years ago.  The guard channel
was 121.5 Mhz which is one of freqs. the PRC-17  and  etc. downed pilot
transceivers (emergency radios) are set up for.

The ARC-27 (the UHF listed in a previous message) had a guard channel of
243.0 Mhz which is the other freq. the emergency radios were set up for.
Most (all?) emergency radios have a xtal for 121.5 and doubled to 243 and
use AM.

73,
Rian

Mike, Marty, Group

The RT-18/ARC-1 and RT-58/ARC-12 both have two complete receiver front ends
(RF Amp, Mixer & HFO/Multiplier Chain), the outputs of which are paralled
into the 1st IF Amp.  However, nowhere in either manual can I find a
mention of the actual frequency or frequencies of the guard channels.  They
just say that the guard channel subassemblies cover a narrow range of
frequencies, and that the radios come from the contractor set up on the
guard channel frequency required by the contract.

The AN/ARC-3/36/49 manual mentions a modification to the R-77/ARC-3 and
R-428/ARC-36 adding a connector for the purpose of connecting the 12MC
output of the guard channel converter (no nomenclature given that I can
find).  The receivers became R-77A and R-428A.  That's all that I found on
the subject.

73
Robert Downs
<[email protected]>
Houston
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