[MRCA] AN/PRC-77 RELEY, RETRANSMITT

[Gary Decker]

 I looked up a cable for the PRC/77 re-trans and they want a $109 for it plus 60+  $'s shipping from Poland. It would be interesting to setup the British radios to do this. I have a bunch of them to bring if needed. Yes, Walt seem like a simpler set-up being that you do not need that expensive cable. Would like to see it in action. Always liked the idea of setting up a portable repeater.  Gene, I did read about the PR 25/77 used to link to helicopters using re-trans to communicate up to distance of 100 miles. Not sure how the Helo config looked since you don't have the antenna separation, unless it was done between two helo's.
    On Wednesday, September 29, 2021, 11:16:24 PM EDT, Walter J Skavinsky <walter.skavinsky at comcast.net> wrote:  
 
 It seems  retrans on the British radios is a simpler process.  There is no requirement for specialized connector cables.  The wireline connection on the side is used.  D10 wire (aka is wd1) is used to connect the radios.  Min Distance is not mentioned in the manual however this requires the use of the surf unit on the radio.  Surf is the “selective unit radio frequency”.  It’s basically an input filter.  This allows the radio to operate in close proximity to other radios on the same bands.  It is possible to operate with his little as 2 MHz separation And requires both units to have properly tune surf which can be done in the field.  

The radios can even be separated in a retransmit station as far as 3 km via wireline so it’s possible that radios from two Forward operating bases that are connected via wireline can be used in a re-transmit operation.  But the co-locating abilities of the 351 is superior to the PRC 77 in its simplicity.

Several years ago I want to say around 2014-ish maybe earlier we set up a re-trans station in the picnic Grove up from the fire company and were able to re-broadcast back to Gilbert.  That day we were actually using both PRC 351 and we even did a cross band re-trans using the PRC 344 on 2:20 AM

I have gained a healthy appreciation for the design and simplicity of the British radios


73 
Walt








> On Sep 29, 2021, at 22:49, Gene Smar via MRCA <mrca at mailman.qth.net> wrote:
> 
> Thanks, Gary.
> 
> It would be fun to try this ourselves but we'd need to find a way to transmit within the 6M amateur band exclusively.� TM 11-5820-667-12 for the PRC-77, p 6-1, states that Cable Assembly, Special Purpose, Electrical CX-4656/GRC is needed to interconnect the two -77s.� It also states that the two freqs must be at least 3 Mc apart.� We'd have to check for interference between our selected freqs by checking the freq compatibility table also in the TM above.� Lots of spurs possible with synthesized radios, I guess.
> 
> I read somewhere, and include this bit of info in my PPT presentation on squad radios, that this relay arrangement was used in Vietnam to enhance comms between troops on the battlefields and artillery batteries miles away.� The relay, I had read, was inside a fixed-wing aircraft orbiting at some low altitude between the battlefield and the artillery.� Can anyone confirm this from his own experience?
> 
> 
> 73 de
> Gene Smar� AD3F
> 
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