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Mic Wiring for use on 10 meter

Posted: Thu May 18, 2006 7:32 pm
by JTNeel
Hello Everybody,

New to the forum here.

Does anybody know if any of the following mics can be wired and used with 10 meter radios? Even on 11 meters?

Motorola Base Mic. HMN1005A
Handhelds: HMN1001B, TMN6013A, TMN6119A, HMN1010A

Radios in question: Voyage VR9000, Uniden 2510

Also, I have some Motorola Traxar radios and a Mostar radio. They are 862-865MHz. Anybody interested? :roll:

Any help would be great here.
Thanx in advance.

Jim

Posted: Fri May 19, 2006 4:17 am
by k2hz
Most Motorola microphones are electret type which require a bias voltage from the radio to operate. Older Motorola microphones used an internal preamp which also required a supply voltage from the radio.

Generally, Motorola microphones will not work with ham/cb radios.

Posted: Fri May 19, 2006 5:15 am
by va3wxm
They may work with Icom HF rigs then since they use electret mics.

Posted: Fri May 19, 2006 12:42 pm
by Will
No, the Motorola mobile radio mics do NOT work on the ICOM radios. ICOM requires/uses a low level audio voltage, and does not have the correct "bias" provision for the Motorola circuit.


Been there, tried to done that, done not work, not going there any more!!!!

You may be better off using the Mic part of a GP300 style speaker mic, it will provide about the correct audio level into the ICOM with the existing "bias" circuit in the ICOM radio.

Posted: Sat May 20, 2006 11:43 pm
by 440roadrunner
Be careful with stuff like Icom radios. The ham versions at least, put the mic voltage right on "top" of the audio--on one wire. You can fry an Icom mic input, by, for example, plugging in a low Z dynamic or other low Z/resistance mike which causes the mic DC to short to ground.

I've lost track of which radios--MO, KW, Icom, or Ysu, do this nasty little trick.


That's why, when you buy things like headsets from Heil, they come with different pigtails for different radios. It's not just the "pinout" at the plug.

WB7TUJ Icom 706IIg

Posted: Wed May 24, 2006 4:36 am
by wd9cms
WB7TUJ has interfaced a Motorola microphone with an ICOM 706mkIIg radio and describes how to modify the mic on his web site http://www.dapcom.com/mobileradios.htm

Posted: Wed May 24, 2006 4:25 pm
by wa2zdy
I used an older preap type M mic 25 years ago with my Icom IC255A without modification of either mic or radio.

I remember it being explained to me then that the bias voltage Icom put on the audio line for THEIR preamps worked just fine with the Ma M stuff.

I've never had occassion to try it since but I know it worked quite well then. The M mic was the only non-Icom mic that worked with Icoms of that era. I do understand that in the past several years Icom has changed their mic arrangements, but I have no Icom stuff except my 25 year old IC2AT, so I can't speak for now.