[Icom] mic's

[Neil Schwanitz]

I agree that the Icom hand mic's are anemic. I rolled my own and used a 
David Clark H10 - 13.4 aviation headset/mic... being a pilot and having 
several of theses in my possession, I figured that I would give it a go.
The mic I am using is 150 ohms and the Icom is 600. 150 ohms and 600 ohm 
in the audio world are both Low Z and do not require any sort of 
impedance matching. Doing so is making more work for yourself and 
potentially upsetting the apple cart.
If I switch back to the Icom hand mic on the rigs... the locals can tell 
and bark about it. VOX performance is excellent too!

The performance of the M-7A noise canceling mic element is wonderful. I 
made an interface which has the up/down switches on it and a PTT switch 
that is (on) off on. This gives me latched in the on position, and 
momentary in the (on) position. I also wired up a foot switch for this.
I recycled a coil cord from an old Motorola mic and added the 8 pin 
connector to the end and then came out of that with a pigtail to connect 
to the HP jack and ran that to one conductor on the coil cord to get RX 
audio to the headsets. I also made an 8 pin to RJ45 pigtail.  Now I can 
use this setup with the IC-820H and the IC-706.

I have never used any of the Heil gear... but he does use Hi-Z (2,000 
ohm) elements and transformers them down to Low-Z.

Aviation headset have two different phone plugs on them, a 1/4" for the 
cans and a 3/16". The 3/16" jack is $$$ and hard to find so I opt'ed to 
use a Nexus jack (used in helicopters) and used my adapter. (I also have 
helicopter David Clark's) This lets me use any of the headsets I have.

These are wonderful for my needs, but at 13.4 ounces some would say that 
they are heavy. Well, they are... but I wear them all the time when I 
fly, so it feels natural to me (except the views from my shack are 
nowhere near as nice!) They are wonderful for nets and terrific for weak 
signal CW. The isolation from the natural world is -23dB. The only 
drawback to these is the XYL has "appeared out of nowhere" and scared 
the living hell out of me a few times because I never heard her coming. 
HI HI.
It is also true that you could buy 3 or 4 of Heil's headsets for the 
cost of a single pair of these... but, being a ham, I used what I had 
around me and enjoy the results.

-- 
Neil Schwanitz
Broadcast Engineer
AAR5OZ /T
WD8CRT




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