Am I correct in thinking to ground the PTT connection to get it to key up? Just looking at the diagrams I have, and seeing a voltage on the pin I would think so. Also Mic audio to ground or is it some other pin?
Thanks for the reply! Wade KC0MLT --- In [email protected], Brian Poellnitz <n4bwp...@...> wrote: > > kc0mlt wrote: > > > > > > > > Hello all, > > > > I am looking for some information on getting the maratrac to key up and > > the audio connections into the radio wjen using it as a repeater > > transmiter. I am powering it with a partial control cable and no control > > head. I would like to be able to use the partial contorl cable for all > > of the needed connections but I am willing to use the RJ45 programming > > port inside the radio if need be. Any help with the connections would be > > very appreciated! (what pin /wires, how to actually get the radio to > > transmit -gnd the PTT???) things like that. > > > > I use a Maratrac as my UHF repeater TX. Interfacing is easy, with a > couple of gotchas. First, the audio and PTT connections are easy. The > RJ45 programming connector at the front edge of the radio uses the same > pinout as most Radius mobiles. Pinout is here : > http://www.batlabs.com/images/maxrad.gif > > Second, programming tips. The best way I have found is to program your > unit for clamshell control head, and delete all modes (channels) except > Mode 1, which is programmed to your TX frequency in both TX and RX. The > gotcha is this: If you have an A7 (advanced) control head, DO NOT hook > it up after you program the unit for clamshell. You will BRICK your > radio, and I'm not sure if Motorola depot repair will take these radios > any more. > > Instructions on powering the radio without a control head are here: > http://www.batlabs.com/maratrac.html about a third of the way down the > page. Basically, pins 17 and 13 to negative, and pins 19 and 4 to +12V. > Make sure your power supply can handle the current draw at your power > level. Speaking of power levels... TURN THE UNIT DOWN to about 60 watts > (assuming you have a 100w drawer) and put a fan on it. This radio is > not designed for continuous duty. Give it all the help you can. Don't > go below 60w, as the radio will overheat due to inefficiencies in the > PA. I've found that dialing back the power and using fans works well in > a light-to-medium traffic machine. > > Oh, one more thing. The Maratrac uses a mechanical relay for TX/RX > switching. The relay will last for a while, but it will eventually > fail. I solved this by removing the T/R relay and running coax > directly from the PA output out thru the hole left by the SO-239 > connector, terminated in an inline SO-239. Of course, the antenna will > no longer be connected to the RX, but hey... we're using this as a > dedicated TX anyway, right? :) > > There you go. That should get you on the way to using your Maratrac as a > dedicated TX. I hope anyone with additional info will chime in as well. > > 73's and good luck, > Brian, N4BWP >
