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  A Transmit Audio Modification for Icom IC-02, 03 and 04 Handheld Radios
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This audio mod works on the 02, 03 and 04AT. It increases the level of the transmit audio (i.e. the modulation), as well as rolling off some of the lows. The result is that sounds much better on the other end. It involves the circuit around Q105.

Modification Steps:

  1. Replace C119 with a .01 uF cap (a disc ceramic is fine)
  2. Parallel R131 with a 1 uF cap (use a tantalum cap)
  3. Parallel R132 with a .01 uF cap (disc ceramic is fine)
There is another mod out there that involves changing C117. Don't do both.

I tried an AB-1 Audioblaster from Engineering Consulting, and was very unhappy with the results. This is much cheaper and sounds better.

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This page originally posted on 01-Aug-2006

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This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.