G4WPW MICROPHONE CONNECTIONS
Apples and Oranges (Honda and Hyundai).
Possible, but you require knowledge (research) for proper DIY interfacing (and not damaging a > $100 Yaesu mic)
START by getting the manuals, schematics and spec sheets!!
IF you own an Icom radio, KNOW the facts about their audio and DC power on that microphone pin !
Icom radios since 1980 primarily use ELECRET microphone elements
INSIDE an ELECRET microphone element (dis-assembly) --
Elecret mic elements still sell for about $3 at your local Radio Shack
Dynamic versus Electret Condenser microphone elements
The output audio signal that a microphone produces will be related to the microphone (element) technology.
Two different classes of microphone are popular in this application area.
One is the dynamic element (e.g. Kenwood, Yaesu), and the other is the electret condenser element (e.g. Icom).
A dynamic element generates a signal which is approximately -55 dBV. An electret condenser element signal is approximately -35 dBV.
That difference, 20 dB, is a 100X difference. Please note that these signal levels do vary quite a bit from microphone to microphone.
Elecret elements require DC power to operate -- DC voltage is provided by Icom radios on the MIC + lead of the Icom radios.
This DC voltage CAN DAMAGE unprotected (DC blocking capacitor) microphone elements (e.g. dynamic, crystal, etc.) --
possibly the Yaesu MD-100 -- You will have to CHECK and see what Yaesu uses in that microphone.
ICOM has designed their radios to expect the higher electret condenser audio level -- and many of their desk microphones (SM-8, SM-20) have a small pre-amp in their bases.
Early iCOM (everything before the PRO series)
Last edited by W9GB; 12-14-2011 at 12:40 AM.
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