Below is a model list for the GTX radios. The model numbering system follows the standard convention for portables and mobiles, if you have a model not listed here.
|Model Number (H=Handheld, M=Mobile)||Radio Model||Conventional Channels||Trunking Systems||Trunking Talkgroups||Band|
*Motorola apparently came out with a new series of GTX portables for 800/900 use. This new GTX portable contains no display nor keypad. Channel selector on top is a 16 position channel selector but will (according to our documentation) only support 12 trunked channels and 4 conventional channels.
If you want to clone these radios, just use the clone feature in the RSS, that's what its for.
If you want to change the band limits for your radio, you need to refer to the Maxtrac page. You will use the same procedure to modify the gtx.mdf file for extended band limits.
900MHz Amateur Radio Conversion
It appears that the Motorola GTX900 radios can be used for Amateur Radio use. These are radios that have a "W" as the third character of the model number.
All you have to do is change the bandsplits in the gtx.mdf using the same procedure as detailed on the Maxtrac/Radius page to something that covers the Ham band, and program the radio.
We have been told that a mobile with the model number M11WGD4CB1AN is currently operating on RX of 927.6125 and TX of 902.6125 with receiver sensitivity of about .15uV and TX power of 15 Watts on 902.6125 and 18 Watts on 927.6125.
As for the portable, one that was converted, TX Power output is higher 1-3W radio wide, and RX sensitivity is better at the top of the band. Example, 927.6125 is 0.20uV or better, 925.0000 is 0.50uV.
Here are a listing of the Service Manual part numbers for this series of radios:
The programming cable for the GTX is the same as the GP300.
These radios are programmed using the GTX RSS.
The programming cable for the GTX is the same as the Maxtrac/Radius series.
The mic connector pinout is the same as the pinout of the Maxtrac/Radius series.
If you make a mic plug with a jumper from pin2 to pin5 (see the schematic above for numbering convention), you will make a "Test Plug" to put the GTX into test mode. Turn the radio on and in 3 seconds the radio's receiver will open up and your in the test mode.
The pinout of the accessory connector for the GTX is below:
|2||External Mic Audio|
|5||Flat TX Audio|
|6||SCI Data In|
|8||SCI Data Out|
|10||Ignition (+12V to turn on radio)|
|11||Flat RX Audio|
|12||General Purpose I/O|
|13||Internal Speaker or Ground or Sw +12V (see below)|
Pin 13 Configuration:
Note: Do not install R0425 if R0426 is installed, this will severely damage the radio!
Looks like the logic board in the GTX is similar to that of the Maxtrac, it may be possible to hack a couple more channels into conventional mode.