Tuesday, 11 October 2016

On Air via Twisted Pair

Today, with some time spare, and having obtained a drum of D-10 twisted pair field telephone cable from Dom at LRSeries-surplus, I finally got to try out the HSR (Handset, Remote) that I picked up at this years Finningley rally. There are two curious aspects of the Clansman system that sometimes puzzle people -1, almost everything is designed with an audio socket to let you plug in a handset! and 2, almost everything is fitted with a D-10 wire stripper!

Also arrived this morning was the replacement 10m audio extension cable. I was just about to get dressed after a nice lazy morning when I saw a parcel van pull up, and knew by the marking on the carton that it was for me!  This replacement is due to the original cable being found to have slipped by with a deep cut that had severed many of the wire cores. Testing both, the replacement proved to be just perfect, but interestingly the damaged cable by sheer luck (bad/good?) had the wires to the earpiece intact! I suspect that any quick test of the cable by just listening for noise, which is how i'd have done it if i had a lot to test, would result in a pass!

I cut off around 15ft of D-10 for the HSR test. I found that I couldnt easily strip it using the stripper mounted on the PRC-351, so cheated there and used pliers. But by a 50/50 chance managed to connect the wire correct way around first time. Attaching the handset is easy, you simply feed in the wire, then pull it back and the Insulation Piercing contacts do the rest. 

Setting the radio to R, a quick check on * showed the audio was working, and going to transmit revealed good sidetone.  Setting to I (intercom) allowed for a successful but tricky test with just one person! A final check on C (Call) showed that the call tone worked just fine.

I only have one PRC-351 so cannot test it on auto rebro. Perhaps when the CRS L/R box comes...

I would have liked to test it on air as well, but as usual theres no 4m activity!

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