maratrax repeater

jeff8153 · Post by **jeff8153** » Tue Jan 04, 2005 10:02 am

We are looking to connect two motorola maratrax mobiles to form a repeater system for our portable radios for use by our drug task force. Has anyone done this before and if so do you have information on how to accomplish this?
Jeff Glenn
Steeleville Police Dept.

Post by **wavetar** » Tue Jan 04, 2005 12:49 pm

Do you mean Maratrac, or Maxtrac?

Todd

jeff8153 · Post by **jeff8153** » Tue Jan 04, 2005 2:12 pm

the units say that the model is maratrax

Max-trac · Post by **Max-trac** » Tue Jan 04, 2005 4:24 pm

Give us a URL to a jpeg.
No such animal that I know of.

psapengineer · Post by **psapengineer** » Tue Jan 04, 2005 6:43 pm

Yes, we've done similar using the GM300, a kin to the Maxtrac. The Maxtracs should have the 16 pin rear accessory connector on each radio. Of course there's programming and set up for both the repeater and any portables you intend to use on it; they will likely need another "mode/channel" programmed for this application.

We used a Motorola RICK to do the interface though you will find cheaper solutions here in Batlabs. We turned down the output power so as not to damage the Tx radio and we used an Astron power supply. You will need a "duplexer" if the radios are operating in the same band.

One word of caution, even though it's "your" channel you will need an FCC license specifically showing this kind of operation, in order to be legal.

Good Luck.

psapengineer · Post by **psapengineer** » Wed Jan 05, 2005 4:14 pm

Try using the Motorola gallery on Batlabs to ID the radio:

http://www.batlabs.com/mgallery.html

Good luck, Bob

kb0nly · Post by **kb0nly** » Wed Jan 05, 2005 7:05 pm

Never heard of a Maratrax. If you can, take some pictures of it and drop me a PM i will give you an email address to send them to, then i will host them and post em for all to see.

I don't know everything about Moto radios, but i sure do know that i have never seen a radio with that model name.

Most likely a Maratrac and the name is fudged or something. Is it trunk mount or a dash mount? Whats it look like, does it resemble any radios in the Moto gallery at the link posted above?

jeff8153 · Post by **jeff8153** » Thu Jan 06, 2005 6:38 am

the radios i am wanting to use in my repeater setup are motorola maratrac. they are remote head mount type radios

jeff8153 · Post by **jeff8153** » Thu Jan 06, 2005 6:58 am

URl for my radio is attachedhttp://www.motorola.com/cgiss/docs/MaraTracMobileRadio.pdf

kb0nly · Post by **kb0nly** » Thu Jan 06, 2005 1:05 pm

Ok, thought so. The Maratrac is easy to make into a repeater. I've done it, nothing to it really. The Maratrac basically has Maxtrac guts running a 100w PA. Most commonly it has a 5 pin logic board. If you follow the instructions available for bringing COS out of a 5 pin Maxtrac its the same for the Maratrac. You can also obtain the RX and TX audio connections as if your connecting together a pair of Maxtracs.

Now, the Batlabs site needs some revisions. Because i noticed that it states "M400 uses a MaxTrac / Radius type VCO board, whereas the Maratrac uses a unique VCO board specific to it", thats bull in my book. I have yet to see a Maratrac with anything other than a Maxtrac board in it. As a matter of fact most of the ones i have seen look like a 5 pin Maxtrac chassis mounted in the Maratrac chassis using the mobile mount holes on each side.

Like so:

The area inside the red square is the Maxtrac chassis. I took a dead UHF Maratrac apart, just removed the screw in each side of the Maxtrac chassis after removing all the connections, and put it to use as a repeater receiver after blanking and reinitializing the logic board as a Maxtrac. Of course i also had to put in a Maxtrac firmware eprom as well.

Anyway, the point i'm trying to make is that its easily done if you treat it like a Maxtrac. You can even eliminate the control heads and cables. The one i built for a local club was with two Maratrac VHF drawers, and a couple ends off some cheap Mitrek cables to supply power and bring out the signals needed for the controller, of course you could also chop up a couple cheap Maratrac clamshell cables, the advanced cables are to expensive to cut up for this use. Program the drawers with one channel and then you dont need the control heads, program them the same, and modify both radios exactly the same. That way if one acts up and your in a pinch to get time to repair it you could just swap the radios around to bypass the bad receiver, or bad PA, etc.

And as far as transmit power goes, keep it set to about 50%. I had them set to about 45-50w, and with a couple fans controlled by a close on rise fan control switch it keeps it running cool enough. The one i use most commonly is a White-Rodgers 3F01-111 from Grainger. It closes at about 110 degrees, and opens at 90 degrees. They also make a surface mount bracket for it, just drill and tap a couple holes in the PA heatsink and mount it on there with a bit of thermal grease. It works best if you take a bit of sandpaper and clean the paint off to get to bare aluminum first. You might want to experiment and find the location that gets the hottest after transmitting a few minutes or better and mount it there. Make sure the metal is thick enough in that location. The best spot i found was on the side of the drawer, just to the back side of the pa compartment.

If you want to go a little more sophisticated, you can get the White-Rodgers 3F05-1, which has an adjustable turn on range of 90-130 degrees, and the turn off is 20 degree less than what you set it to. So if you set it to turn on at 90 it would turn off at 70. But it costs about $20, compared to the set range 110 degree unit that only costs about $9.