Motorola Mostar Radios

FAQ

** Please note that much of the information on the Internet about the Mostar radios is incomplete at best and in many cases inaccurate.**

** What frequency bands did the Mostar radios cover?

The Mostars were offered in 3 different frequency bands:

  • 800 mhz trunked (3rd digit in model number will be a "5")
    • These are pretty much useless for any use other than for use on an 800 mhz trunking system
    • They can not be converted to amateur use !!!
  • UHF Conventional (450-470 mhz) (3rd digit in model number will be a "4")
    • These can be converted to 440 mhz amateur frequencies with proper programming, tuning and alignment
  • VHF Conventional (150.8 -174 mhz) (3rd digit in model number will be a "3")
    • These can be converted to 2 meter amateur frequencies with proper programming, tuning and alignment

 

** What are the different UHF / VHF Mostar models?

The UHF / VHF Mostar radios were offered in 2 different production models:

  • NVR Model (early)
    • NVR stands for Non Volatile Ram
    • The upper (command) board on NVR Mostar models can be identified by its red color
    • The NVR Mostar models use a 70C020 Non Volatile Ram to store the codeplug data
    • The NVR Mostar radios came with the following channel configurations:
      • 1 channel - (no buttons / channel select switch)
      • 2 channel - (uses a push button switch to select channel 1 or 2)
      • 8 channel - (uses a rotary channel select switch)
  • Display Model (later)
    • The "Display" name means that the radio is capable of having a display. It may or may not actually have a display!!
    • The upper (command) board on the Display models can be identified by its green color
    • The Display models use either a 2804 eeprom to store the codeplug data in a radio with up to 16 channels
    • The 32 channel Display Mostar uses a 2816 eeprom to store the codeplug data
    • The Display model Mostar was offered with the following channel configurations:
      • 1 channel - (no buttons / channel select switch)
      • 2 channel - (uses a push button switch to select channel 1 or 2)
      • 8 channel - (has a single digit LED readout and up / down channel select buttons)
      • 16 channel - (has a two digit LED readout and up / down channel select buttons)
      • 32 channel - (has a two digit LED readout and up / down channel select buttons)
    • The number of channels a Display Model Mostar can suport is hardware by the microprocessor.
      • The 1, 2 and 8 channel Display radios use microprocessor # 51-97003C11
      • The 16 and 32 channel Display radios use microprocessor # 51-97003C09  

 

** How can I tell if a radio is one of the dreaded 800 mhz models?

There are several ways:

  • Look at the 3rd digit in the model number
    • 5 = 800 mhz trunked
    • 4 = UHF (450.0 - 470.0 mhz)
    • 3 = VHF (150.8 - 174.0 mhz)
  • Look at the front of the radio
    • An 800 mhz Mostar will not have a squelch control knob
    • An 800 mhz Mostar will not have an LED display
  • Look at the rear of the radio
    • The antenna connector on the VHF and UHF radios is one side of the heat sink and the power connectior is on the opposite side
    • The power connector for the 800 mhz models is in the center of the heat sink  

 

** What is the difference in a "NVR" Mostar and a "Display" Mostar?

  • NVR Mostar
    • The NVR radio (NVR stands for Non Volatile Ram) and was the first production version of the Mostar.
    • The upper (command) board on NVR Mostar models can be identified by its red color
    • The NVR Mostar models use a 70C020 Non Volatile Ram to store the codeplug data. The memory capacity of the NVR limited the number of channels to a maximum of 8.
  • Display Mostar
    • The "Display" Mostars were the later production radios.
    • The upper (command) board on the Display models can be identified by its green color
    • The Display models use either a 2804 or 2816 eeprom to store the codeplug data. The choice of eeprom is determined by how many channels the radio has.
  • General Differences / Similarities
    • The later Display Command Board is fully interchangeable with the earlier NVR Command Board. In fact you will see many Mostars that have a red RF circuit board but have the newer green display command baord.
    • The command boards are not band dependent, you can swap a UHF to VHF radio (or vice a versa) and load the proper codeplug and you are off running.

** What do the model numbers mean?

 

** How many channels can my Mostar have?

The number of channels depends on the command board in the radio (NVR or Display), the microprocessor, the eeprom and the method to select channels: 

  • A single channel radio can be converted to 2 channel radio by adding a push button switch. 
  • A single channel radio can be converted to 8 channels by adding either a rotary switch or an LED readout, depending on the model. 
  • A NVR model (red command board) radio can have a maximum of 8 channels
  • A Display model (green command board) radio can do either 8, 16 or 32 channels depending on the microprocessor and memory eeprom.


** Can you increase the number of channels in a Mostar?

Yes, we offer several enhancements to the Mostar.  Please visit our Mostar Enhancement Page for more details. 



** Why is it so hard to get a Mostar programmed?

The Mostar was one of Motorola's earliest synthesized (programmable) radios and were sold during the 1980's. They can be programmed by several methods:

  • A Motorola R-1801 suitcase programmer with the appropriate software / programming adapter card / cable. 
  • Motorola (Epson HX-20) laptop with the side car adapter / appropriate software and cables.
  • An IBM XT compatible PC using RSS software and a Mostar Interface Box (MIB) 

We have all three programmers available in our shop, while most other two way shops disposed of their Mostar programming equipment years ago. The programming equipment does show up from time to time on ebay or govdeals..

 

 

**What is a MIB (Mostar Interface Box)?

  • The Mostar Interface Box is used with the PC Radio Service Software to program the Mostar. It only works with the Mostar
  • The MIB provides the necessary interface to program the codeplug information into the NVR / eeprom.
  • Externally the MIB looks identical to the later RIB (Radio Interface Box)
  • Internally the MIB and RIB are totally different.



     

     

**Do you have the schematic for a MIB?

    • Short answer is yes, we have a schematic, but it is not for sale.
    • If you would like a schematic for the MIB, we suggest that you do what we had to do - buy a MIB and spend several weeks reverse engineering the board.

 



** Can you program the Mostar with ham frequencies?
  • Yes, but the radio will need to be tuned and aligned to operate properly.

     


** Can you program the Mostar with GMRS frequencies?

The Mostar is FCC type accepted for Part 95 (GMRS), but it can only be programmed on the following GMRS frequencies:

         
  462.5500 mhz  462.575 mhz 462.600 mhz 462.625 mhz  
  462.6500 mhz 462.675 mhz 462.700 mhz 462.725 mhz
  467.5500 mhz  467.575 mhz 467.600 mhz 467.625 mhz 
  467.6500 mhz  467.675 mhz  467.700 mhz 467.725 mhz 

The Mostar will not accept any of the 12.5 khz splinter channels such as 462.5625 mhz, 
462.5875 mhz, 462.6125 mhz, 462.6375 mhz, etc.


** Can you program the Mostar with FRS frequencies?

No.  The Mostar is not type accepted for FRS.


** Will the Mostar accept splinter frequencies?

The VHF can be programmed with splinter frequencies.  The UHF radio will
not do splinter frequencies.

** Is the Mostar capable of narrow band operation?

No, the Mostars are wide band only.

 

** Can the Mostar do different PL or DPL tones on transmit and receive?

 Yes, you can do different PL or DPL tones on transmit and recieve.

 

** What is the maximum frequency spread for a Mostar?

Per the service manaul the maximum frequency spread for a Mostar is:

 
Band
Receive
Transmit
 
VHF
4.0 mhz
10.0 mhz
 
UHF
1.5 mhz
6.5 mhz

Normally we can tune for 6 mhz on receive and at least 10 mhz on transmit with a slight reduction in receive sensitvity / transmit power

 

 

** What are the pin outs for the 15 pin accessory plug?

The "standard" pin out for the rear connector is:

  • Pin 1 Int speaker high / speaker B / PL / DPL  (jumper selectable)
  • Pin 2 Mute
  • Pin 3 Volume High or DPTT (jumper selectable)
  • Pin 4 GND
  • Pin 5 Switched A+
  • Pin 6 Carrier
  • Pin 7 Filtered A+
  • Pin 8 GND
  • Pin 9 Buffered Detector Output
  • Pin 10 Ext PA Speaker / ID data ( (jumper selectable)
  • Pin 11 Mike PTT
  • Pin 12 Monitor
  • Pin 13 Mike Audio
  • Pin 14 Int PA speaker / Mike Mute (jumper selectable)
  • Pin 15 Receiver (Speaker) Audio

An external speaker is normally connected to pins 8 and 15

The functions of pins 1, 3, 10 & 14 are determined by jumpers on the command board.