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DIY PCB conversion MTM800/GM360 for remote head

Posted: Mon Jul 23, 2018 10:48 am
by wkb
Got the suggestion @EEVblog forum to go ask in this forum as the Motorola wizzos gather here. So..

I am in the process of fitting a remote head ("control unit") to my Motorola MTM800 Tetra mobile radio. On these radios you
can remove the head unit from the radio, add an interface box to the radio, another interface box to the head unit and fit a RJ50 (10 wire) cable
to link them together.

OK.. the problem at hand is that I have a remote head including the interface PCB. I lack the interface PCB that goes onto the radio body.
Having borrowed a specimen of the latter I learned that both ends of the cable use the same base PCB. It is just that the module that goes onto
the radio body has more parts fitted, like for example a voltage regulator.

Right.. I have some spare PCBs of the "remote head" variant, so the lesser populated version.

What I lack are the schematics of the modules to determine which parts need to be fitted to morphe my "remote head module" into a "radio body module". I am specifically interested in the SOT23 parts.

Who can help me to the schematics??

Pics are at http://www.eevblog.com/forum/rf-microwave/looking-for-schematic-for-motorola-mtm700mtm800gm360-remote-head-pcb/msg1677197/#msg1677197

NB1: GM360 analog radios use the same module type it seems.
NB2: there are multiple variants of these modules, I found schematics for the other module types, just not for the ones I have
NB3: the MTM800 works fine with a straigh-through 8 wire cable with RJ45 plugs fitted. So standard UTP cable will do, just make sure it is a 1:1 cable.
NB4: where I live we have a DMO Tetra repeater operating in the Dutch 70cm ham band allocation.

thanks, 73,
Wilko