[MRCA] Retransmit

[W2HX]

Ok, so I confirmed that the PRC-138 has the same pinout as the Rt-1439 (prc-119).  So I just bought some cables, CX-13298, which I believe to be cross over cables in the way Al has described below.  If luck is on my side, it may be as simple as connecting the two radios using this cable and maybe also setting a squelch level on the PRC-138.  If I can get this working, I can run the PRC-138 with my 125W amp and the RT-1439 with my 30W amp.  Fun fun!

BTW: I see the U-183 cable mentioned. But also on PRC68.com I see the following 
http://www.prc68.com/I/FillCbl.shtml
" This is a cryptographic fill cable with a U-183 (6 pin U-229) on both ends.  It has all 6 pins wired straight through."

Straight through seems to not be what we want.  But maybe there is another version of the -183 or maybe a misprint on the website.  According to the sincgars manual, the RXMT cable is the CX-13298 (I have two coming to me).

 
73 Eugene W2HX
 

-----Original Message-----
From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of Al Klase
Sent: Monday, August 27, 2012 4:53 PM
To: Military Radio Collectors Association
Subject: Re: [MRCA] Retransmit

Eugene,

From: http://www.prc68.com/I/Audio.shtml#Ret

QUOTE:
On some radios there is a connector labeled RETRANSMISSION that is used with other similar radios to make a simplex repeater.

The (U-183) retransmission cable used with the RT-1439 is cross wired as
follows:

B ->D
D<-B
E->C
C<-E
F--F (TTL Hi = Analog mode, TTL Low = Digital mode) A--A END QUOTE:

I think we can assume similar pinouts to the standard  to the standard
U-228/229 audio connectors;

Pin
Audio Function
A - Ground, Negative Battery
B - headphone audio
C - PTT (ground to send)
D - Microphone audio
E - Vehicle B+ on the PRC-68 & PRC-126,
Retransmission (switch to ground when receiver squelch opens) on PRC-25, -77, RT-246

There's a potential issue with audio levels.  Perhaps, the RF-1439 retrans connector takes care of that.

Al


On 8/27/2012 2:13 PM, W2HX wrote:
> Hey guys. I've been doing some research on interconnecting one of my harris HF units with my RF-1439 set up (VRC-89 I think).  The harris RF-5020 has this capability I have learned. J5 carries a retransmission key line output as well as 4 balanced audio signals. 2 RX audio and 2 TX audio. In addition, through menu options, I can set these audio levels to either 0 dBm or -10 dBm.  Interestingly, the PRC-138 does not seem to have a retransmission capability which is somewhat surprising.
>
> As Ray noted, the 1439 does also have retransmit capability.  However, despite the millions of pages of various TMs I have on singcars, I cannot seem to find any technical details of the pin outs for the RXMT connector (6 pin) and what audio levels it is expecting. Anyone have technical details on this?
>
> Also, while I'm here, anyone know the MS connector number for J5 on the harris 5020? I looked in my operations and maintenance manuals and there was nothing.  I've already floated the question on the harris reflector.
>
>
> 73 Eugene W2HX
>
>

--
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

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