[MRCA] Military mobile repeater

[Mike Morrow]

The heart of Korean War-era FM sets capable of retransmisson (AN/GRC-3 to -8; AN/VRQ-1 to -3) is the C-435/GR retransmission control that installs in the MT-297/GR or MT-298/GR.

The AN/GRC-3 to -8 uses one RT-66, -67, or -68/GRC plus RT-70*/GRC.  The manual contains detailed charts of the frequencies for the two RT units which are compatible in retransmission service...many many combinations are not.

I have a complete AN/GRC-7 including R-110, RT-68, RT-70B, PP-112, PP-282 (x2), AM-65, C-375, C-435, MT-297.  It was magnificent world-class state-of-the-art technology for 1949, and today it still looks magnificent all put together...all 240 pounds of it.  I have found these sets to be fascinating ever since I saw my first RT-68/GRC in 1968.

I have the 1960s (and later) era AN/VRC-47 (R-442A, RT-524A), but I don't find mostly solid-state stuff nearly as interesting.

Mike / KK5F

-----Original Message-----
From: Robert Downs <wa5cab at cs.com>
Sent: Aug 12, 2021 2:02 AM
To: 'Ronnie Thomas' <sgtthomas75 at gmail.com>, <mrca at mailman.qth.net>
Subject: Re: [MRCA] Military mobile repeater

There were probably some informal or ad hoc setups during WW-II using two SCR-508, SCR-608 or one of each but AFAIK they did not assign a specific nomenclature to the set.  But the AN/VRQ-1, -2 and -3 along with the MT-298/GRC were specifically for repeater service.  The MT-298 held two of the large RT/s and two of the Vibrator Power Supplies.  Although I don&rsquo;t think that specific nomenclature was assigned, there was nothing preventing you from using two different RT;s instead of two of the same model The only restriction would be that the higher frequency RT couldn&rsquo;t be on a harmonic of the lower frequency one.  
 
And note that this makes a bi-directional repeater, not the type commonly found today in the USA on 2-Meters.  Perhaps Relay Station might be a better description of the function.
 
The same thing could be done with the AN/VRC-12 family sets except that there was not a mount made to carry two of the RT&rsquo;s.
 
At a halt, two of the RC-292 low VHF ground plane antennas were commonly used with AN/VRQ-1,2,3 or the VRC-12 equivalent/
 
Robert Downs
 
From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of Ronnie Thomas
Sent: Monday, August 9, 2021 12:02
To: mrca at mailman.qth.net
Subject: [MRCA] Military mobile repeater


I have read that the Army at one time used mobile repeaters in the field. I was wondering if anyone has any information about this. I would like to know if it's possible to set one up. 
Thanks 

Ronnie 





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