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  Conversion of Motorola Mitrek Mobile to 6 Meters
by Wes Nicholas KD3IJ
This page was developed by Mike Morris WA6ILQ from an email posted by Wes Nicholas KD3IJ on the Repeater‑Builder Mailing List
Thanks go to Wes for permission to present his work.
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Notes from the Editor (WA6ILQ):
The model number mentioned in the email below is for a carrier squelch radio with the extender option.   The modfication below should work on all high-range low band Mitreks.
For information on the various model numbers and chassis numbers please look at the Mitrek Model and Chassis Numbers web page.

This is a simple modification that consists of moving the top end of the RF circuits from 50 MHz to 54 MHz.   No changes are made in the audio or control circuits.

From: Wes Nicholas KD3IJ
Date: Mon, 22 Sep 2003
Subject [Repeater-Builder] Mitrek 6 meter mods

Hi all, there was a request for some info on converting a Motorola Mitrek to 6 
meters,and after I volunteered I had done it I got lots of requests for some 
info. So here is what I did to "move" mine up the band.

First I have a Mitrek model number T51JJA2900AK 4 channel 60 watt mobile with 
KXN1085A RX channel elements and KXN1087A TX channel elements.

All capacitor values below are in pf (picofarads).

RX Preselector changes: 
                         C104 was 22PF now 10PF
                         C106 was 22PF now 10PF
                         C108 was 22PF now 10PF
                         C110 was 22PF now 10PF

Local oscillator/multiplier changes:
                         C152 was 16PF now 8PF
                         C153 was 68PF now 33PF
                         C155 was 13PF now 7PF
                         C157 was 14PF now 7PF

TX Exciter changes: 
                         C701 was 16PF now 8PF
                         C703 was 24PF now 12PF
                         C707 was 33PF now 18PF
                         C710 was 22PF now 12PF

There was a "hidden" adjustment in the channel elements, a "tank" coarse 
setting possibly? that needed to be adjusted to get enough signal to the 
injection amplifier.The elements were tuned to operate at 46 MHz and had 
to now operate at 53 MHz.

My radio was the high-split 39-50 MHz version. When I was finished the RX 
sensitivity was 0.16uv for 12DB sinad and 60 watts output. RX specifications 
call for 0.3uv. These mods were made by trial and error, but turned out very 
well. I basically went about half of the cap values and had lots of adjustment 
range in the tuning cans.

I hope that this helps!

Oh, by the way, I do have a real Mitrek manual (60 watt version).

73, Wes KD3IJ


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Original text (the white background) © Copyright Wes Nicholas KD3IJ
HTML by Mike Morris WA6ILQ
this page last updated 23-September-2003

Mitrek® is a registered trademark of Motorola Inc.

The information presented in and on these conversion pages is © Copyrighted 1995 - 2003 by Kevin Custer W3KKC and multiple originating authors.