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From: kube@cogsci.berkeley.edu.BERKELEY.EDU (Paul &)
Newsgroups: net.aviation
Subject: military to civilian headset conversion
Message-ID: <11634@ucbvax.BERKELEY.EDU>
Date: Fri, 31-Jan-86 03:19:11 EST
Article-I.D.: ucbvax.11634
Posted: Fri Jan 31 03:19:11 1986
Date-Received: Sat, 1-Feb-86 07:16:20 EST
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: kube@cogsci.berkeley.edu.UUCP (Paul Kube)
Distribution: net
Organization: University of California, Berkeley
Lines: 36

Last year I submitted a request to the net for information on getting
a military-type headset to work with civilian radios.  No help from
the net, alas; but meanwhile I've been able to find out the following:

1.  The M87 microphone found on many military surplus headsets is not
a bad microphone; it's still used in military applications, and in
three commercially available headsets I now know about:  AudioCom,
Carter Engineering, and Sigtronics models.   The problem with it is that
it is a dynamic microphone (and a very low impedance one at that:
5 ohms), and your typical GA comm expects a carbon mike.

2.  It ought to be simple to build a M87-to-carbon converter with
an FET or two and a few passive components, but I wasn't able to find
a public domain design.  However, each of the companies making M87-
based headsets sells a converter, so you can take your pick
from the following list.  (I bought a couple AudioCom converters
because they were cheaper than the others; they also had the best
price on replacement microphones.  They work, but I don't have
anything to compare them to.)

	AudioCom Electronics
	2134 Dickerson Road
	Reno, NV 89503		(702) 747-5000

	Carter Engineering Co., Inc.
	232 South Glasgow Avenue
	Inglewood, CA  90301	(213) 649-0111

	Sigtronics
	822 N. Dodsworth Avenue
	Covina, CA 91724	(818) 915-1993

--------------------
Paul Kube
kube@berkeley.edu
ucbvax!kube