Motorola MX Portable FAQ
How do I know if my MX portable is programmable (synthesized)?
Can the MX portables be programmed with an IBM compatible computer ?
What is the difference between an "A", "B", "C" or "D" Memory Modules ?
How do I find where the memory module is located ?
I have a "A" or "B" version memory module. Do I have to buy a new module ?
What are the band splits for the MX's ?
Can my MX be programmed out of its band split ?
What is the maximum frequency separation for the MX's ?
Can the PL tones be programmed in the Memory Module ?
What is the "T" knob on top of
the radio?
How do I know if my MX portable is programmable (synthesized)?
The programmable (Synthesized) MX radios have a model number that has SSU or SXU for the 4 -6 digits. An easier method is to look at the top of the radio and see if it says "MX 300-S". Click here to see a picture of a MX-300-S
Can the MX portables be programmed with an IBM compatible computer ?
No - The MX radios require a Motorola R-1801 programmer to program them.
What is the difference between "A", "B", "C" and "D" version Memory Modules ?
There have been at least 4 different memory modules for the MX. They are denoted by the last letter of their part number.
"A" and "B" version memory modules are PROMS (Programmable Read Only Memory) which can only be programmed one time.
"C"
and "D" version memory modules are EEPROMS (Electrically Erasable
Programmable Read Only Memory) which can only be reprogrammed many times.
Follow this link to our MX Memory Module Removal &
Identification Page
I have a "A" or "B" version memory module. Do I have to buy a new module?
Possibly not. The "A" or "B" module may have some unprogrammed zones that can be programmed with the frequencies that you want. This is usually the case with a 12 channel radio. There can be as many as 3 empty channel zones available, that can be "selected" by installing the proper jumpers inside the radio.
In order to know which jumpers to install to access the unprogrammed zones, You will need to purchase a service manual for your radio. Call Motorola at 1-800-422-4210, or look on Ebay.
If you don't want to go to the trouble to order an manual, we can configure the jumpers along with tuning and aligning the transmit and receive of the MX for an additional $45.00 per radio.
How are the memory addresses divided?
The Memory Module is divided into 4 zones with up to 12 channel per zone (16 channels for certain SP models). Banks are selected by a either a toggle switch or an "A-B-C-D" zone selector switch located on the top of the radio.
How do I find where the memory module is located?
Follow this link to our MX Memory Module Removal & Identification Page
What are the band splits for MX Radios?
The band splits for MX's are determined by the components inside the radio. Band splits that I know of are :
VHF
136-150 mhz
150-162 mhz
162-174 mhz
UHF
403-430 mhz
450-470 mhz
470-512 mhz
Can a MX be programmed out of its band split?
Yes, to some degree. You can usually slide the operating "window" by a few Mhz by retuning the VCO and realigning the radio. A 450-470 MX can usually be retuned to cover the 440 mhz ham frequencies.
What is the maximum rated frequency separation for the MX's?
VHF Transmit - 10 mhzVHF Receive - 3 mhz with 3db degradation
UHF Transmit - 12 mhz
UHF Receive - 5 mhz with 3db degradation
Can the PL tones be programmed in the Memory Module
No - The PL or DPL tones are not programmable. They are selected by installing the proper Permacode tone element in the radio if the radio is equipped for PL or DPL tones.