[MRCA] MRCA Meet Recon Patrol Operations

[Gene Smar]

Gents:

     FWIW:  There is a special cable that is/was used with a pair of 
PRC-25 -77's to retransmit audio from one to the other.  The cable includes 
a connection that utilitizes the grounding of pin E of the connector from 
the opened squelch to activate the PTT of the other unit.  Could one 
possibly use this same signal on pin E to activate the PTT of another, 
non--25 or -77 radio?  And vice versa?

     Here's the e-mail I wrote on the subject on August 31, 2009:

All:

After a bit of reading in my TM for the PRC-77 I see that the
CX-4656/GRC cable assembly uses Pin E in one radio's connector to pull to
ground the PTT line in the opposite connector when the first radio's squelch
opens. Pin E becomes active in this way when the -77 (and -25, I assume) is
placed in retransmit mode. The cable assembly includes a box that has small
capacitors to ground and steering diodes for the PTT lines, plus
inductors/chokes in series with all lines (audio and control.) Should all
be easy enough to fabricate if one wanted to.

There is one issue with using this assembly with two -77's in
retransmit mode: The two antennas and their TX freqs must be far enough
apart that desense is minimized. The TM recommends a minimum channel
separation of 3.5 MC (physically, the units with their antennas are to be
placed 50 feet apart - the length of the cable.) For us to be able to use
this technique at Gilbert or elsewhere we would need one freq just below 54
MC (say, 53.90) and another at around 50.40. This is permitted by FCC Rules
but it eliminate 51.00 from possible use.

That's enough for tonight. G'night, all.


73 de
Gene Smar AD3F
----- Original Message ----- 
From: "Ken Downs" <krtdowns at myfairpoint.net>
To: "W2HX" <w2hx at w2hx.com>
Cc: <mrca at mailman.qth.net>
Sent: Sunday, August 26, 2012 8:51 AM
Subject: Re: [MRCA] MRCA Meet Recon Patrol Operations


> Back in 1980-82 when I was stationed at Ft Lewis, WA with the SHORAD 
> battalion (1/67th ADA),  a higher HQ ran a division-wide air defense 
> warning net using a crossband setup. They tied an RT-524 VHF rig and a 
> GRC-106 HF rig together somehow. It worked pretty well, but I think it was 
> one-way cross-band - VHF in and retrans out on HF until they figured out 
> how to get the HF rig to key the FM set. I believe the GRC-106 has no 
> squelch, or if it does, they could not get things going very well 
> HF-to-VHF. They may have eventually come up with a custom outboard VOX 
> box. I was not directly involved with it and do not remember how they did 
> it. The concept was brought to Germany for a test (along with some other 
> stuff) during an exercise at one point and seemed to work pretty well. 
> Might be fun to play with using two back-pack rigs.
>
> Ken, W1KRT
>
> On Aug 25, 2012, at 3:25 PM, W2HX wrote:
>
> Ok, I've never attempted the retransmit idea, but I'll see if I can figure 
> something out between my HF sets and VHF set (PRC-119 with or without amp)
>
>
> 73 Eugene W2HX
>
>
> -----Original Message-----
> From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] 
> On Behalf Of Radio Station KW1I
> Sent: Saturday, August 25, 2012 3:19 PM
> To: mrca at mailman.qth.net
> Subject: Re: [MRCA] MRCA Meet Recon Patrol Operations
>
> Gene, Eugene and Al
>
> Al is correct.  The 51.1 mHz is a typo.  FM liason comms will be on the 
> 51.0 mHz frequency we have used in the past.
>
> Eugene,
>
> If you can engineer the HF to 6 meter link, go to it.  It would add a new 
> dimension to our "scientific inquiry" efforts.  I think most if not all 
> the stations will be able to copy each other on HF if we have good NVIS 
> conditions.  As Al reported Penns Peak and Big Pocono have line-of-sight 
> to the fairgrounds.  Beltzville can copy both Penns Peak and Pocono and if 
> I recollect some ability to get into the fairgrounds.  Lake Minsi and 
> Jacobsburg are pretty isolated on 51.0 and may have no FM comms to any 
> other station.  FM coverage comments from previous MRCA radio ops at those 
> sites are invited.
>
> Dale
>
>
>
>
> ______________________________________________________________
> MRCA mailing list
> Home: http://mailman.qth.net/mailman/listinfo/mrca
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:MRCA at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> MRCA mailing list
> Home: http://mailman.qth.net/mailman/listinfo/mrca
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:MRCA at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> ______________________________________________________________
> MRCA mailing list
> Home: http://mailman.qth.net/mailman/listinfo/mrca
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:MRCA at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html