Microphone switch

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  • Updated 2 years ago
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This isn't necessarily a Flex related project, but I thought it was worthy enough to post here on the Flex Community board just the same.

A couple of weeks ago I went to a Hamfest and found a 4 position DB25 switch.  These things can be found all over the place including Good Will.  The one I found was in nearly perfect condition and after bringing it home and cleaning it up, I was quite happy with my $3 purchase.  This is a really nice 4 position switch that was used to switch modems or some other such equipment that used the DB25 connector.  It is in a very nice metal enclosure with all of the DB25 connections coming out of the back of the box.  Believe it or not, the switch actually controls all 25 pins of the DB25.

Initially I had planed on removing all of the wiring, add a new back panel with 8 pin plugs and wiring it up as so I could use my PR40 microphone to go to all of my rigs.  I figured with a little bit of work, I could get rid of all of the microphones in the shack and have a single PR40 with a foot switch/thumb switch for all of my rigs.

Just prior to gutting the wiring inside the box, I happened to be at Fry's Electronics and noticed they had these really nice (male) DB25 to RJ45 adapters.  The best part was that pins for the RJ45 portion of the adapter were loose and could be plugged into any pin position of the DB25. (programmable). I saw this and though, it was just way to easy to set up adapters so that I could use standard Ethernet cables to go to just about any radio in my shack.  So, I purchased 4 adapters at $3.89 each, brought them home and started to configure them.  The adapters are large enough to accommodate just about any additional components you might need.  In my case, I added a 1.0 uF capacitor on the MIC+ line to prevent bias voltage from coming up into my PR40 Dynamic Microphone or shorting out the MIC+ line of my Icom radios. There is lots of room in these adapters, so an old guy like me can even feel pretty confident in wiring them up. 

I came up with a standard of my own on the DB25 cable to accommodate just about any data I could possibly use in the future.  Since I didn't care about up/down and some of the other features, I did keep the bios voltage line in case I wanted to ever use a ribbon or electrolytic mic and I reserved 3 wires within the DB25 to carry the CW paddle, bug or straight key.  So not only does it switch the mic and PTT, it also switches the paddle to any of my rigs.

I now have a very nice box on my desk that enables me to use my PR40 on a boom with a foot switch and my cw paddle, bug and straight key to any of 4 radios in my shack.  No more microphone and wiring clutter on my desk. No more un-plugging and plugging in my key or paddle from one rig to the next.  Everything looks clean and very tidy!   All of this for under $20.  So keep an eye out for what is in those junk boxes at the Hamfests!

Norm - W7CK
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Norm - W7CK

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Posted 2 years ago

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Photo of EA4GLI - 8P9EH - Salvador

EA4GLI - 8P9EH - Salvador

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Pictures please!!