Batboard

The way that Maxtracs work the "user" or programmer can't specify the design band limits. I have run into this before with low band, vhf and uhf radios. The RSS will work for setting the power just fine, but when you go out of band (for example to 144.51 with at 146-174 split) the OS of the radio just lets the tx run wide open. The only fix that I was hoping someone may have found is to BIT BANG the PROM and tell the radio to use the normal power limiting from 903 to 927. As it is the radio quits controlling the tx about 903 up to 931. works fine above that and below that. I alreay have worked up the LM917 regulator in the CONTROLLED b+ line, I was just looking for a "prettier" fix.

It has been a while since I fooled with a Maxtrac. I will be working on several soon, however, so I will need to face the same problem . I recently ran into the same thing with a MTS2k. I actually found the test frequencies in the software and changed them. When I selected the service menu, it displayed the new frequencies I had edited. When it keyed the radio, it was still transmitting on the old frequencies. I believe those test freqs are in the radio firmware. I believe the same thing happens with the GTX also. What about Spectras?

As I said above the test freqs and the "control" band limits are in the radio OS (prom). Changing the freqs in the RSS just allows entry of the freqs to the memory of the radio. So it will operate on the "out of band" freqs but the control circuits don't function. I have found a very few radios that seem to work ok no matter where you program, but I am betting it is a different production run or someting. BTW I have an MCS2K on 900, works OK, but only the 902 & 927 areas. Won't do the whole band. And the squelch is VERY tight at min. So I just use the PL decode to gain the needed sensitvity.

The MTS2K I have won't do talk around. I am going to modify the talk around vco so it will. The receiver sensitivity doesn't seem to be as good as the GTX down at 927. I am going to remove the first preselector filter and jump it to improve it. This is not something I would suggest for everyone because it makes the frontend wide as a barn door. I have tried to find an alternate filter and have actually found one in Toko's catalog that looks like it would work. Doubt if I could get just one though. I was able to snag some of the small, surface mount 915E-10's off E bay.