Out of Band Modifications
OK, here is an easier method to doing out of band modifications to the Maratrac than previously reported. And, even better, it includes information on all the available bandsplits.
Open the file indicated in your hex editor (such as Hex Workshop) and apply the changes you want, you do not need to correct a checksum once your changes have been made.
The tables below show the locations in the file corresponding to each bandsplit. The first set of locations listed correspond to what is displayed in the Radio Wide Configuration screen as the bandsplit of the radio. The second set are the ones that affect what the RSS will allow you to enter and program into the radio.
Radius M400 Version 2.00 Modifications
We only have the locations for the 450-470 bandsplit.
It appears that you can program the Maratrac with Radius M400 RSS.
The modifications apply to the M400OVL2.OVL file.
Displayed bandsplit:
Hex Offset Hex Value Decimal Value Frequency (MHz) B186 9411 4500 450.0 B18D 5C12 4700 470.0
Programming bandplit:
Hex Offset Hex Value Decimal Value Frequency (MHz) DBA8 9411 4500 450.0 DBAF 5C12 4700 470.0
Radius M400 Version 2.01 and 3.00 Modifications
The modifications apply to the M400OVL2.OVL file.
Displayed bandsplit:
Hex Offset Hex Value Decimal Value Frequency (MHz) B141 2901 297 29.7 B148 6801 360 36.0 B152 6801 360 36.0 B159 A401 420 42.0 B163 A401 420 42.0 B16A F401 500 50.0 B174 E100 225 22.5 B17B 2901 297 29.7 B185 5005 1360 136.0 B18C 1806 1560 156.0 B196 A005 1440 144.0 B19D CC06 1740 174.0 B1A6 BE0F 4030 403.0 B1AD CC10 4300 430.0 B1B6 9411 4500 450.0 B1BD 5C12 4700 470.0 B1C6 5C12 4700 470.0 B1CD 4C13 4940 494.0 B1D6 4C13 4940 494.0 B1DD 0014 5120 512.0
Programming bandsplit:
Hex Offset Hex Value Decimal Value Frequency (MHz) DD9D 2901 297 29.7 DDA4 6801 360 36.0 DDAE 6801 360 36.0 DDB5 AE01 430 43.0 DDBF A401 420 42.0 DDC6 F401 500 50.0 DDD0 E100 225 22.5 DDD7 2901 297 29.7 DDE1 5005 1360 136.0 DDE8 1806 1560 156.0 DDF2 A005 1440 144.0 DDF9 CC06 1740 174.0 DE02 BE0F 4030 403.0 DE09 CC10 4300 430.0 DE12 9411 4500 450.0 DE19 5C12 4700 470.0 DE22 5C12 4700 470.0 DE29 4C13 4940 494.0 DE32 4C13 4940 494.0 DE39 0014 5120 512.0
Maratrac Version 4.02 and 4.03 Modifications
The modifications apply to the MARATRC2.OVL file.
Displayed bandsplit:
Hex Offset Hex Value Decimal Value Frequency (MHz) 17080 2901 297 29.7 17094 6801 360 36.0 1709E 6801 360 36.0 170A5 A401 420 42.0 170AF A401 420 42.0 170B6 F401 500 50.0 170C0 E100 225 22.5 170C7 2901 297 29.7 170D1 5005 1360 136.0 170D8 1806 1560 156.0 170E2 A005 1440 144.0 170E9 CC06 1740 174.0 170F2 BE0F 4030 403.0 170F9 CC10 4300 430.0 17102 9411 4500 450.0 17109 5C12 4700 470.0 17112 5C12 4700 470.0 17119 4C13 4940 494.0 17122 4C13 4940 494.0 17129 0014 5120 512.0
Programming bandsplit:
Hex Offset Hex Value Decimal Value Frequency (MHz) 19B17 2901 297 29.7 19B1E 6801 360 36.0 19B28 6801 360 36.0 19B2F AE01 430 43.0 19B39 A401 420 42.0 19B40 F401 500 50.0 19B4A E100 225 22.5 19B51 2901 297 29.7 19B5B 5005 1360 136.0 19B62 1806 1560 156.0 19B6C A005 1440 144.0 19B73 CC06 1740 174.0 19B7C BE0F 4030 403.0 19B83 CC10 4300 430.0 19B8C 9411 4500 450.0 19B93 5C12 4700 470.0 19B9C 5C12 4700 470.0 19BA3 4C13 4940 494.0 19BAC 4C13 4940 494.0 19BB3 0014 5120 512.0
Now that you know what locations you have to change, you need to figure out what to put in. It is fairly simple to figure out, you can use either the Base Converter in Hex Workshop, or any ordinary calculator that can do DEC-to-HEX conversions.
For example, if you wanted to change the low end of the 450-470 bandsplit radio from 450 to 440... as you can see from the above pattern, you will need to convert 4400 from decimal to hex. When you do this you should get 1130. All you have to do is swap the high and low order bytes and you get 3011.
This is the number you would replace the 9411 with and there you have it, your radio will now be able to be programmed from 440-470. Note however, that just because you can program the frequencies into the radio, it doesn't mean that the radio will work well there, if at all.
Modifications for Effective 6meter Use
Some information regarding moving the Maratrac out of band (50 to 54 mhz):
The Maratrac is a real bear to modify for amateur use. Its front end is designed for 42 to 50, and that's about it. Above 50, it rolls off very steep and is useless in the FM portion of the band. Also neither the transmit or receive VCOs will lock reliably much above 51 so you'll need to change out the coils (available from Digikey). Fortunately, the injection oscillator, exciter, and power amplifier are pretty flat and you won't need to make any changes there. The one nice thing is that the only physical modifications that are needed are all on the RF board. You don't have to hack the radio apart. You can install a stock RF board and return the radio to stock condition. With the modified board, your radio will now operate from about 46 to 54 MHz and you'll lose the 42 to 46 MHz sensitivity (if you can lock the VCOs)
In addition to the VCO coils, you'll need to make extensive modifications to the RF board (like changing out 20 or so chip capacitors). Its a good idea to sweep the entire front end before making the changes to try and shift the front-end curve up by 4 MHz. When you finish, if you're lucky, the sensitivity should be about spec. (0.35uV for 12 dB SINAD).
It's a nice radio but a lot of work to convert, not to mention the need for the software that will allow you to program it out of band.
The bottom line is that, unless you like spending few bucks on parts and several nights working under a magnifying glass, stick with the crystal bound radios - this one wasn't designed for amateur use.
Converting to 99 Channels
Converting to 99 channels is fairly straight forward. First, you need the "advanced" control head (looks like a cheap X9000 head) and control cable. The radios are the same whether they are 8, 16 or 99 channels, it is onle the control head that is different.
Then, all you have to do is power up the radio, it doesn't matter if it has the advanced or clamshell head, go into the Service Menu, and change the radio control head type to Advanced.
That's it, go back in program in your extra channels.
General Information
Check out the programming cable. Now, don't email us asking why this is the cable since you can't find anywhere to plug it in to. You have to pop the lid on the transceiver and there is a jack on the front interconnect board where you plug in programming cable.
The 16 ch and the 8 ch camshell head are electrically the same. The only differnece is the label and what the switch label says. All you have to do is change it to clamshell with scan in the RSS and program the scan list and also the hang-up box, if used, has to go between pins 24/27 not 27/30.
You can find the pinout of the control head cable here.
The pinout of the VIP connector on the A7 head should be something like this:
Pins 4, 5, 20, 21, 37, 38 go to the Siren Interface Pin 4 = Mic High Pin 5 = Analog Ground Pin 20 = PTT In Pin 21 = Digital Ground Pin 37 = PTT Out Pin 38 = On/Off Pin 35 = Hub Pin 36 = Hub Ref Pin 19 = Emergency Ref Pin 3 = Emergency Pin 2 = Horn Relay Pin 34 = Light Relay Pin 1 = VIP Out Pin 18 = B+
The siren for the Maratrac can be used in a stand-alone application, you do need the DEK (direct entry keyboard) with the control buttons in order to use it though.
If you want to add PAC-RT operation to the Maratrac you need cable part number NKN6214B which has been modified for special application SP09. Click the link to see the wiring diagram of part number NKN6214BSP09.
If you are adding PAC-RT to the Maratrac, you will need to do the following modifications:
This modification routes mobile receiver audio to the PAC-RT using the transmit LED wire. Transmit light function is disabled. These modifications are from the Motorola service bulletin and are to be used in conjunction with the above cable.
