© 2003-2011 by Harold Melton, KV5R. All Rights Reserved. Rev.06/11/05
Micorphones and the Icom 706MkIIG
If you really want to connect another mic:
The 706 uses an 8-pin “modular” RJ connector for the microphone. This is the same as used by CAT-5 computer LAN (network) cables. The connector costs $4+ each and requires a rather expensive assembly/crimp tool. My way is, of course, much better.
- Go to office/computer supply store.
- Buy a nice soft CAT-5a LAN patch cable, one with nice molded strain relief plugs. Get a 10-footer.
- Cut off one end, or cut in half to make two mic cables.
- Ring out and document pin numbers to wire colors.
- Solder the conductors into your mic or other audio accessory.
You can find an old, classic mike and replace the element in it with a modern electret condenser. (See photo) ElectroVoice Mercury and Shure Unisphere A. The Shure has been modified with a dual-element electret, PTT switch, and CAT-5a cable.. I don’t use it because the sound quality is inferior to the stock mic…
- The supplied HM-103 hand mike is the best one you can run on the 706. I do NOT recommend using other mikes on the 706, except the Heil iCM series. Other mikes, including Icom desk mikes, will have a sound clarity that is inferior to the stock hand mike (yes, really)… The HM-103 sounds best when you talk across it. Never place it flat against the mouth as this will cause considerable distortion.
- Rewire the mic’s on-off switch for PTT.
- Wire the element always “hot” or you won’t be able to use VOX.
- On the other hand, a mic off switch is useful when running SSTV where you need to talk then transmit SSTV.
- Obtain a quality electret condenser mic assembly, designed for 8 volts DC phantom power. A setreo mike element, used on cam-corders, may be wired in parallel, and you’ll get lots of output that’s needed by the “pre-Pro” Icom radios. These will not sound as good as the stock hand mike.
- Bob Heil will not sell you a bare iCM element, even if you beg!