Adding an Artillery Command Post to a Military Vehicle Collection – Part 5 – Progress with Testing

Snakes and Ladders with Radio sets

Now where were we?

VHF ATU and AdapterIn the last instalment I had collected a number of parts which would go towards the radio installation and I was waiting for the cabling which connects the VHF sets and their components together. This arrived last weekend so I thought I would have a go to see whether the 353s worked. There was nothing to suggest that they would not, as they formed half of a batch bought from a dealer and the other two worked fine.

IMG_2850Harness

The first concern was that although the plugs on the cables I had bought matched the sockets on the radio bits, the labels showed that most were in fact designed for other uses. I was slightly annoyed about this as the whole point behind using that supplier and paying the price asked was that he told me he had the correct cables. I could have bought other cables which would plug in for a bit less and been in no worse a position. The bright side was that one pair were actually labelled correctly so I have a known good pair and I have tested the pins to see how they are connected and can then compare those to the others.

Power Supplies

My first test was to power up – the power supply I had was a simple 24 volt charger connected via a made up lead, terminating in the two pin clansman connector. I assembled the parts, connected the power, turned on and nothing. I turned it on a couple of times but with exactly the same result. I could not hear anything moving or working. At this stage I ran out of time so set it aside for another day.

Apparently Dead

My next trial involved another set with the same ancillaries, but this time I set it up indoors. My reason was to see whether any of the set lit up as the first time I did it, I couldn’t see anything. I followed the set up in the user manual to the letter and turned it on. Not quite nothing, but as close as you can get. A few more tests and some close observation indicated that the lights in the frequency selection window were lighting up briefly and then there was a clunk and they went off. They did this within a second or so of the power being switched on so it was very difficult to tell what was happening. When the switch was turned to 28 volts, the meter showed that the power supply was in the green, but at any other position the set appeared to be completely dead.

 Reading The Manual

From the fault finding schematic in the user manual it pointed to the power supply unit in the radio tripping, and the advice was to switch on and off to reset. This merely repeated the process, and the worrying thing was that the next stage on the flow chart was that the set was faulty.

There’s Life Jim…

This is where the Clansman Radio User Forum came in. I posted a request for help and received some very good advice. The consensus was that the voltage from the battery charger was not “clean” enough for the radio. That is to say that there were fluctuations in the voltage that made no difference when charging a battery, but which were completely incompatible when used to power radio equipment. Stuart posted a link which explained the situation perfectly and set me looking for another way to power the set. (see here…) On the good side, it was felt that the radios were performing as expected by tripping when faced with an unregulated power supply.

Testing….

One. As I mentioned earlier, I brought a couple of signals batteries down from the vehicle to try to recondition them so I had these in the garage. I made a better power lead with terminals that connected properly to battery posts and a lead to connect the two batteries in series to give me a smooth 24 volt supply. In the assembly of the set I checked as much as I could and found that I only had eight volts across the two batteries. Whilst I was disappointed I was not surprised as I did not have a lot of confidence in the batteries. However, I connected one to the charger for an hour or so and managed to lift the voltage up to about ten and it was taking reasonable amperage so there is hope that once I get them up to charge they will have enough in them to run the set.

IMG_2851

I did get some life into the batteries and connected everything. Turned the sets on and Bingo – lights where there should be and clicks and whirrs all round. It worked with both sets, so I am fairly confident that I have the basis of a radio fit. Over the holiday I hope to change the components around to test cables and boxes. Plymouth Radio Club are having a 24 hour event on Good Friday, so I hope to receive some traffic on the 50Mhz band just to test reception.

Two. That apart there has been some progress with the RB44 and it is now booked in for its VOSA test in the middle of April. I have checked with DVLA and they tell me that the registration process should only take 48 hours before I get the authority to make the number plates which puts it on the road. The V5 will follow, but it will be taxed and insured and ready to drive. Looking at my diary I am aiming to take some time off around the 10th May and bring it home then.

Three. Not only that but I passed my foundation licence exam. I have not been allocated a call sign yet, but will look and see whether TUH is available, TUH standing for Truck Utility Heavy, the designation of the RB 44.

Even the sun is shining here!  Albeit a tad late 😉

 

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