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and M400
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Maintained by Robert Meister WA1MIK

Information and Modification Articles:

An Overview of the Motorola MaraTrac Mobile radio   by Robert Meister WA1MIK and Jim Kalkowski N1GTL
The MaraTrac is like a MaxTrac on steroids. Up to 99 channels, 100-110 watts, remote-mount. This article shows what's inside a UHF unit and a low-band unit. The Radius M400 is similar. There are some MaraTrac scans on the main Motorola page.
Activating the MaraTrac Remote Squelch Pot   by Robert Meister WA1MIK
It seems many of these low-band radios come equipped with the remote squelch pot, but the radio doesn't know it's there. This article shows what seems to be the problem and how to fix it.
MaraTrac Interface Signals for Repeater Use   by Robert Meister WA1MIK
MaxTracs can be used as repeaters, so why not their big cousins? This article identifies the signals available in MaraTracs (More Power!) and suggests an interface method. If you're going to build a repeater, use the MaraTrac as the transmitter as it's much better suited for longer transmit time. Use a MaxTrac as the receiver because it's much easier to get a COR signal out of. You can buy pre-made cables for this configuration on a popular auction site.
MaraTrac Manual Power Control   by Robert Meister WA1MIK and Dave Malicki N1OFJ
MaraTracs, like MaxTracs, are often used on frequencies slightly out of their normal ranges. They also suffer the same indeterminate transmitter output power problem. This article shows how to add a manual power control adjustment pot specifically for the MaraTrac.
Investigating the MaraTrac Squelch Circuit   By Robert Meister WA1MIK
The MaraTrac claims to have an adaptive squelch circuit that produces a longer squelch tail when the signal is noisier. A low-band radio is tested to see how this works.
How the MaraTrac Controls Transmit Power and Deviation   by Robert Meister WA1MIK
This article describes why the MaxTrac radios need manual power and deviation controls. Since the MaraTrac uses an identical logic board, the same techniques apply equally well. Here we tell you how a replacement program EPROM can fix this problem once and for all.
The Motorola Control Cable Connector Virus   by Robert Meister WA1MIK
While this happened to some MaraTracs, it can also happen to a lot of other remote-mount radios that have control head cables and connectors. This article tries to explain which came first: the bent pin or the bad cable connector. It shows the problem and how to fix it.
Replacing the Dallas Memory Module In the MaraTrac   By Scott Withrow KC9LQV
Radios that use the Dallas NVRAM will be losing their memory when the battery goes dead. They have about a 20 year lifetime, so any radio made prior to about 1992 will have this problem and the Dallas chip will need to be replaced. This article tells you what to do about it. While aimed at the MaxTrac, the MaraTrac suffers the same ailment.
Permanently Disabling the Extender on a Low-band MaraTrac Radio   By Robert Meister WA1MIK
A simple jumper disables the noise blanker. This is necessary for radios that will be used as base station or repeater receivers.

Manuals, Brochures, Guides, and other printed material:

MaraTrac VHF Low-Band Service Manual   6880102W95-O   10 MB PDF   Donated by Eric Lemmon WB6FLY.
MaraTrac VHF Low-Band Remote Squelch Supplement   FMR-1735A-1   3.7 MB PDF
Donated by Bob WA1MIK, scanned by Eric Lemmon WB6FLY. Supplement for the low-band service manual above.
MaraTrac VHF High-Band Service Manual   6880102W18-A   8.2 MB PDF   Donated by Eric Lemmon WB6FLY
Covers the radios with "AK" as the last two characters.
MaraTrac VHF High-Band Service Manual   6880102W94-O   16.6 MB PDF   Donated by Eric Lemmon WB6FLY
Covers the radios with "BK" as the last two characters.
Radius M400 Service Manual   6880901Z56-O   16.6 MB PDF   Donated by Eric Lemmon WB6FLY
This one manual covers all three splits / ranges on low-band, 150-174 MHz VHF, and 450-470 MHz UHF models. For all intents and purposes, the M400 radio is identical to the MaraTrac but it uses a different RSS. The M400 is to the MaraTrac like the Radius is to the MaxTrac; same hardware but sold through different channels.
This manual also has Installation Instructions.
An Official MaraTrac VHF Sales Brochure   1.2 MB PDF
An Official MaraTrac Accessories Brochure   90 kB PDF
A transcription of the Advanced Control Head (A7) Operating Manual (fold-out card)   125 kB PDF
Scans of the Hand-Held Control Head (HHCH, A5) installation diagram and control cable   185 kB PDF

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This page was created 08-Oct-2011 from stuff on the main Motorola page.

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.