Maxtrac and Radius Mobiles

MAXTRAC/RADIUS

In typical Motorola fashion, the Maxtrac and Radius line of mobiles are really the same radio! The only real difference is the actual firmware of the radio. All of the info provided here should work with varying degrees of success depending on the features of the original radio. The Service Manual is crammed full of stuff and would be well worth ordering if you plan to do any experimenting with the radio. The part number of the Service Manual is 6880102W84 for the Maxtrac and it contains info on all models of the radio (Low, VHF, UHF, and 800 MHz).

Do you need a pinout for the 16 pin ccessory connector, the 5 pin accessory connector, or the mic connector, or how about the programming cable?

Do you want to program frequencies outside of the normal bandsplit? For a Maxtrac look at Maxtrac, for a Radius look at Radius.

Do you want to convert a 900 MHz Maxtrac to work in the 902-928 MHz Ham Band? Take a look at this text file. You may find that the Murata filter has been discontinued. You can use a TOKO p/n 6DFB-915E-10 as a replacement (available from AVNET electronics). If you don't mind playing with small components, you could also use a TOKO p/n 4DFB-915E-10 which is a SMD dielectric filter with the identical specifications, it is available from DIGIKEY. The conventional firmware part number you may need is FVN4019A.

If you're playing with Trunking Maxtracs and TrunkTrackers, you may be interrested in this conversion spreadsheet. It is a Microsoft Excel document. It converts Motorola Talkgroup ID's to Maxtrac ID's and TrunkTracker ID's.

You've got a Maxtrac/Radius that you want to tune up on 6m... check here.

Having RSS errors? Look at the Radius Series RSS Error Codes

Need to connect a couple of Maxtrac/Radius radios together? Here is a schematic of the R.I.C.K. to get you started. Order the service manual part number 6880901Z79 from Motorola.

An alternative method of linking 2 Maxtrac/Radius type radios together can be found here.

Some people's voices just suck when broadcast over a Maxtrac/Radius due to the the cutoff frequencies used in the TX Audio stage. Here is modification to make the audio more pleasing to the ear.

The Maxtrac/Radius Series are 9600 baud packet capable. They do need a minor modification though. For RX, its no big deal, just take RX audio from PIN 11 of the Accessory Connector and swing JU551 to the (A) position (Flat RX Unmuted). For TX audio, you will have to run a jumper to the junction of R223,C228,R222 on the RF board to inject the data (if applicable you may need to set the deiation pot in the radio to maximum). You might want to put a pot on your TX line somewhat like the setup Motorola uses (voltage divider) to adjust the deviation. It would be wise to do some measurements to make sure you have the deviation correct. You might also want run the RX and TX pins to the unused pins on the front mic connector after the mods are done.

If you are playing with a Trunked Maxtrac, here is the information on putting the radio into test mode.

You can convert a trunking Maxtrac or Radius back to conventional operation. You will need to replace the trunking firmware in the radio with conventional firmware. You will then need to blank the logic board with Lab RSS, and re-initialize it as a conventional radio. Note that before changing the firmware and blanking the board, you should write down all the alignment settings in the radio.

If you have a TDN8310A DTMF microphone from a Maxtrac and are looking for a schematic for it... look no further. We do not know of a proper source for the schematic (which service manual), however, it is almost identicle to the VLN1017A DTMF microphone for the MCX1000. You can look at the Tone/Logic Board and the Microphone/Beeper Board schematics. Note that the part designations in these schematics are slightly different for the TDN8310A, but it is better than nothing. This board layout will make locating the proper jumpers a bit easier.

Do you want to use a PAC-RT with a Maxtrac? You will need the following cable:

MaxTrac					PAC RT
Acc Conn.	
	3  -------------------- 6
	13 -------------------- 1
	11 -------------------- 21 (Shielded Cable)
	2  -------------------- 19 (Shielded Cable)
	7  -------------------- 8 
			  ----- 2
			  |
			  ----- 16
			  ----- 10
			  |
			  ----- 17

Cable shields are connected to PAC-RT Pin 18 (Ground) and not connected at radio. There are two jumpers inside the PAC-RT Connector, Pin 2 to 16 (B+) and 10 to 17 (PTT Ground).

For on-off control:
PAC-RT	Pin 2 B+ to on/off switch  
	Pin 9 & 15 other side of on/off switch 
(Pin 9 = PAC on/off, Pin 15 = Portable in/out) 
Both must be connected to B+ for unit to turn on,
Pin 22 ground (not required, unless you want an indicator lamp, or something).

Information Common to Both Maxtrac and Radius

Since these radios are so much alike, lets start with some things you and do that apply to both series of radios.

Codeplug Checksum Location

If you happen to be messing around in the codeplug file, be aware that the first 0x2D bytes need to have the proper checksum (stored at offset 0x2E).

For example, if you wanted to calculate the checksum of the following header in a codeplug file:

You would select the bytes and do a 1's Complement Hex Checksum calculation.

The Checksum-8 value is the one you want to enter into offset 0x2E. In this case you can see that they already match.

We've been told that the same applies if you are changing the serial number of the radio using the EEPROM access feature of Lab RSS. The nice feature of using the Lab RSS is that it has the option to correct the checksum for you.

Location of Model Index in Codeplug

First, lets take a look at an example from a .mdf file:

The highlighted entry contains all the info for a specific model of radio.

For the particular model selected, the index that refers to this radio is this:

Now, if you open the saved file (codeplug) for your radio, you'll see something like this at the beginning of the file:

Now, the tricky part of this is, the index isn't stored in one location. The red bytes are the index. Notice they match the index bytes you found in the .mdf file.

The significance of knowing the index number for your radio comes to when you start modifying the .mdf file for specific features in your model of radio. If you were to search for your model number in the .mdf file, you will have more than one hit, but, they each have unique index numbers...

Add Channels by Editing the .MDF File

This information is common to both the Maxtrac and Radius lines. Depending on which logic board and firmware is in your radio, this may or may not work. The example screenshots shown are for the Maxtrac version R06.01.00c RSS.

Open the MAXTRAC.MDF or RADMBL.MDF in your Hex editor, Hex Workshop is an excellent program for this. The Maxtrac and Radius RSS don't do any checksum checks of the file so you don't have to worry about correcting the checksum later.

Search for your model number in the file, you probably will come accross more than one entry so you can either change them all or use the information above to locate the proper index to change a specific model.

Once you find your model entry you should see something like this:

If you look at this model entry, the third byte after the model number (offset 0x1036) is a 0x20.

This is the hex representation for the number of channels in the radio, in this case 32 ch. Depending on your radio you might want to try changing this to 0x10, 0x20, or 0x28, or higher to give you 16, 32, and 40 channels respectively.

Also note the 0x02 at offset 0x1034, this is the bandsplit identifier for this radio and corresponds to the table entry at the top of the .mdf file.

The 0x01 at offset 0x1035 refers to the power level of the radio.

To find out if you picked the correct model number to edit, save the .mdf file and load your radio's codeplug into the RSS. Try adding channels with the Mode Utility and see what happens.

One thing you have to be careful of is that the RSS will let you put as many channels into it that you want, what the radio will accept is another thing. It appears that once you exceed the maximum number of channels for a radio and try to program them in, the firmware will "wrap" the extra data around to the beginning and start programming from channel 01. You will be able to tell if you have exceeded the maximum number of channels by trying to program in one channel at a time until it "wraps", ie. if the maximum number of channels your radio will take is 16 and you try to program 17 channels into it, once programming has finished you will find your radio will only show 1 channel. Another thing that might happen is that if you exceed the number of channels programmed into the radio, the display will show funny things as you scroll through the channels, it depends on the firmware in the radio.

Codeplug Hacking

Well, if you are brave enough to mess around in the codeplug using the EEPROM Access feature of the Maxtrac Lab RSS, there are some things you should know.

With version R07.02.00a Maxtrac RSS and newer, the codeplug errors you may get when reading the radio have been expanded from the usual Error #58 into a bunch of different codes. Depending on what the code is, determines the block of data in the codeplug which is corrupted. The blocks we have identified so far are as follows:

Address B600h to B62Dh, checksum at B62Eh, Error #58
Address B62Fh to B639h, checksum at B63Ah, not checked
Address B63Bh to B67Eh, checksum at B67Fh, Error #59
Address B680h to B68Bh, chechsum at B68Ch, Error #60

If you use the Fix Checksum option (F6) the software will correct the checksum for first block listed (B600h to B62Dh).

So, if you are hacking around in the codeplug (or changing the serial number), the locations of the checksums for each block will be important.

To calculate the checksum for a block of data, you will have to enter the data into Hex Workshop (version 2.54) manually. Once the block of data is enterred, highlight all the bytes except the checksum byte and hit F12 (Calculate Checksum). Make sure the Selection, Hex, and 1's Complement options are checked off, and click Generate. The value that is generated in the Checksum-8 field is what you want to use for the checksum for the block of data when you modify it in the RSS.

MAXTRAC: Try using the "Shift method" same as with the Radius and see if your version of RSS supports it. Otherwise, well, you will either need to do some Hex editing of your saved file or get a copy of the LAB RSS.

If you are going to use the Hex editing method, see the steps below.

In the MAXTRAC.MDF file make a Checksum-16 of the whole file (the F12 option in Hex Workshop), in our case we ended up with 0x4528 (RSS V 06.00), write this down, you might need it later.

Look starting at about offset 0x2BA, you should see something like:

The highlighted area contains all the bandsplits recognized by this particular RSS.

A single bandplit entry in the table looks like:

If you look carefully at the highlighted portion, you should notice the following items>

02 00 = Bandsplit identifier (Note: it is at the end of the frequency assignments)

E4 05 = 1508 in decimal, ie 150.8000 MHz

54 06 = 1620 in decimal, ie 162.0000 MHz

Note there are 3 occurances of the strings E4 05 and 54 06, and another set of limits, 50 05 and 72 06. The first set is the limits displayed in the Radio Wide menu (F4-F2). The second set are the TX limits for the radio. The third set are the RX limits for the radio (note that if the TX and RX limits are not set the same the RX limits are screwed up). The fourth set are the limits that the radio is spec'ed to go and that Lab RSS would let you program (only giving an "Outside of FCC Limits" error), in this case the limits translate to 136.0000 MHz to 165.0000 MHz.

If you program outside these limits the Lab RSS reports that the frequencies are "Outside of FCC and Radio Bandwidth Limits". In other words, if you want to have your radio operate properly, don't exceed the limits in the "Lab" field.

To figure out what hex to enter for your bandsplits you can either use the Base Converter (in Hex Workshop), or use a calculator with a HEX --> DECIMAL conversion function.

If you are using a calculator enter your limit (ie 1360 for 136.000 MHz) and convert it to hex, you should get 0x0550. When you enter the data into the .mdf file you have to reverse the bits such that you would actually enter 0x5005 in the field you are changing.

If you are using Hex Workshop, launch the Base Converter utility and select "Intel Byte Order". Then, enter your desired frequency and write down the hex result.

You can then directly enter the hex result (0x5005) into the bandsplit field.

In this example we are changing the lower bandsplit of a 150.8-162MHz radio to 136-162MHz.

Save the new file (you might want to make a backup copy of the original if you haven't already.

Some of the RSS packages (we don't have codeplugs for everything, so we can't check them all) check the checksum of the .mdf file when you try and load a codeplug and return an error if the checksum of the .mdf file doesn't match the one stored in the program. Try running the RSS with the new .mdf file, if you don't get an error when you run the RSS and load a codeplug then you don't have to worry about the next step.

Correcting the .mdf File Checksum

If you get a corrupt .mdf file error then you will have to go back and correct the checksum in your edited .mdf file. Load the file back in your hex editor and make a Checksum-16 of the file. If you compare the new checksum

with the original one

You will find they are probably different.

The only way we have to correct the checksum of the file at this time is to keep editing bits and making Checksum-16 calculations until the edited file's checksum and the original match. You can either edit the Copyright statement or some of the model descriptions in the file. Just take one or a few of these insignificant bytes (some experimentation may be required depending on by how much the cheksum is out) and add or subtract a few bits of the numbers make a Checksum-16 of the file. You should notice the checksum has changed by the number of bits you added or subtracted. Keep going until the checksum's match.

Once the checksum's of the files match you should be able to run the RSS, load the codeplug, and enter the frequencies within your new bandsplits with ease.

Changing Band Limits in Maxtrac RSS Version 5.03

Search for F6 46 FE 01 75 03 in file MOBILE5.OVL and change the 0xF6 to 0xC6.

Search for B8 00 00 76 01 and change the 0x76 to 0xEB.

You can now program any frequency in, it is a matter if the hardware will do it.

Adding Type II/IIi Trunking to a Type I Maxtrac

First off you must start with a B5 B6 or B7 model (has to be 16 pin ACC)

The second step is to obtain a type II firmware chip for a Smartnet Maxtrac, the part number is HLN9383.

Next, you need to blank the logic board using Lab RSS.

Re-program the logic board with your trunking RSS so that it is now a Smartnet radio (either a C3, C5, or C6).

Realign the unit and you now have a unit capable of type I,II, and IIi.

Making a Maxtrac do Pac/RT

The only information we have received so far is that this can be economically achieved by using a RICK unit, or building one yourself and plugging it into a second MaxTrac.

The second MaxTrac can be a simple 2-channel unit (or not) and will two-way repeat the first one and vice-versa.�You can also construct this device to one-way repeat (just eliminating the second TX line) to contruct a GMRS repeater out of two MaxTracs.

RADIUS:

Life can be a lot easier for Radius owners. All you have to do is load your file into RSS, go the channel you want to program, when you are in the field you want to change, use the shift key and the numbers across the top of the keyboard to enter the frequency. Fill the entire field and make sure you release the shift key when you enter the decimal point. ie. 139.5500 would be !#(.%%)) Its as simple as that.

If the above method doesn't work, then you'll have to do some hex editing.

In the RADMBL.MDF file make a Checksum-16 of the whole file (the F12 option in Hex Workshop), in our case we ended up with 0xA402 (RSS V 08.00), write this down, you might need it later.

Look starting at about offset 0x29E, you should see something like: