Thursday, October 11, 2012

A Simple Manual Antenna/Radio Switch

Now that I have three RockMites and one FT 1000MPV to play with I wanted to make it easier to switch from each radio, the simple solution was a basic antenna/radio switch.  
I had an old 3 way Altai switch from years ago but quite honestly it was a cheap bit of kit and anything above 50 watts it would probably burn out. So I decided to build my own using various bits of junk I had in the shack.  
I pinched the four SO239s from the Altai which were fine but interestingly on further inspection the Altai was definitely on its last legs, the plastic switches on it were virtually worn away. After rummaging further in the shack I managed to find another SO239 to make 5 connectors in all.
I also had a small aluminium/aluminum enclosure which would do nicely for the case and being metal would take care of the groundings and any stray RFI. I found a one pot 4 way rotary switch, but it was plastic job, fine for a guitar or something similar but I doubt would have lasted very long for what I wanted.
So I decided to buy something heavy duty and after trawling around the web I found a UK company that sold 1960s rotary switches and I spotted a good solid 1 pot 4 way switch that would be just the job.

It cost me £6 but when it arrived I knew I’d bought the right switch, it was a good solid bit of kit, nice and heavy with a break before make connection.
I soldered some 14 gauge wire to the SO239s and fitted them to the enclosure, after cleaning up the switch I drilled another 16mm hole in the top of the enclosure and fitted it in to place. 

Finally I connected up all the 14 gauge wire from the SO239s to the switch and gave it a smoke test. The SWR was good on all five connections and another useful bit of kit was completed. 

The nicely thing now is that I'm not chopping and changing antenna connections to different radios all the time, with a simple twist and satisfying "clunk" of the heavy duty switch I can connect to each radio with ease.

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