[Milsurplus] ARC/GRC(27)

[Jim Whartenby]

Checking the manuals, the ARC-27 weights in at 70 pounds while the GRC-27, which has three components, receiver, transmitter and modulator / power supply has a combined weight of 385 pounds.  The respective volumes are 2.25 cubic feet verses 8 cubic feet.  The respective power levels are 9 watts and 100 watts nominal on any of 1750 frequencies between 225 and 400 mc/s.  This is a power difference of only about 10.5 dB.
 
I have never seen an ARC-55 either in USAF or at numerous Hamfests.  I have seen a few ARC-27 over the years, if fact I bought one with the mount for next to nothing 30 years ago in eastern PA.  So my guess as to why the ARC-27 over the ARC-55 is simply availability.
 
The ATC tower at Mactan did use one GRC-32 which is as already mentioned an ARC-27 plus the biggest 28 VDC power supply I ever remember seeing.  It was run outside of the case which was necessary since the tower had no air conditioning!  Base Ops had a GRA-53 or 54 which is also a UHF transceiver comparable the the ARC-27.
 
GRC-27s were used in permanent installations while the ARC-27 / GRC-32 were temporary installations although temporary could mean many years of service.
 
This discussion brings back many fond memories,
Jim



----- Original Message ----
From: Jim Haynes <jhhaynes at earthlink.net>
To: WA5CAB at cs.com
Cc: milsurplus at mailman.qth.net
Sent: Sat, March 6, 2010 3:37:26 PM
Subject: Re: [Milsurplus] ARC/GRC(27)

On Sat, 6 Mar 2010, WA5CAB at cs.com wrote:

> I am curious, though, as to why they would have used the ARC-27 instead of
> the unpressurized AN/ARC-55, which I presume would have been lighter,
> cheaper, and had ventilation.

I'm curious why they used the ARC-27 in place of the GRC-27 - but maybe 
the answer is that they had run out of GRC-27s and had tons of ARC-27s
left over from refitting the airplane fleet with later model radios.

Mention has been made of poor reliability of the ARC-27s compared with
the ARC-3s, yet Collins was pretty proud of the ARC-27.  So perhaps
the ARC-27 was better that previous equipment when used in airplane
service, but no in ground service.



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