Kenwood MC-60 to ICOM IC-746
Last Updated: 19 Jan 2005
At a Ham Fest last year I purchased a Kenwood MC-60 microphone with the intention of using it with my ICOM IC-746 transceiver. Figuring out the microphone and PTT connections was pretty straight forward. However making the Up and Down switch work with my ICOM was not that straight forward. Kenwood uses separate lines for the Up and Down functions while ICOM uses one. Having other things to do at the time, I simply hooked up the microphone and the PTT switch and used it without the Up/Down function.
Now I'm sorry I took so long to get back to the project. After doing some investigation I figured out (using the original ICOM microphone) that the Up function on the ICOM was achieved by grounding pin 3 on the ICOM microphone connector. The Down function was done by grounding pin 3 through a 470 ohm resistor. The solution was simple. Add a 470 ohm resistor across pins 3 and 4 on the back of the connector in the base of the MC-60 and connect pin 4 of the microphone to pin 3 on the ICOM.
Headset Microphone Jack
I have recently performed another modification to my MC-60. I had been wondering how the headsets that Radio Shack sells for cordless phones would work with my ICOM. I wanted to use the VOX capabilities on the ICOM while calling amateur nets. The Kenwood desk microphone picks up too much background noise for that purpose. I finally decided to take a chance and bought one of their noise canceling headsets (RS Part: 43-1952). I was not disappointed. I have gotten very good remarks on my audio quality and the headphones are great for picking out the hard to hear signals.
I had made a simple adapter to connect the headset to the radio but I then decided it would be better to add a quick connection to the desk microphone. I was unable to get a 3/32" stereo jack that would disconnect the desk microphone when plugged in, so I changed the plug on the headset to a 1/8" stereo plug (RS Part: 274-284). I then used a 1/8" closed circuit jack (RS Part: 274-246). See the diagram below for wiring.
Note: Other Radio Shack headsets may work with the ICOM but I have not tested these.
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