Batboard

I have installed a VHF Maratrac in a 1993 Toyota Celica and am having problems with the radio. When I key up, it works fine for about one full second. My meter shows ~ 100 watts and the audio sounds fine. However, after a second, the power drops for the rest of the transmission. I can hear the signal using a handheld or other radio within about 100 feet of the Maratrac, but beyond that I cannot hear the signal at all. The power is so low that it doesn't even register on the meter.

I felt that perhaps the problem was the grounding and so I moved the ground connection from the chasis to the (-) battery terminal thinking that would take care of the problem if it were indeed a grounding issue. This did not help.

At this point I figured the problem had to be within the radio. I tried a different Maratrac drawer and experienced similar problems. With this drawer the power remained low during the entire transmission--so low that it also would not register on the meter. The only difference in drawer #1 and drawer #2 was the fact that #2 didn't transmit the full 100 watts for a second at the beginning of the transmission as drawer #1 did. Once again, I checked all connections. I tried a different antenna (knowing this probably wouldn't be the problem). Also, I went into the service section in RSS and checked the power output settings.

I have no idea what to do next. Perhaps both drawers are bad? The odds of that being the case seem low though. Is there any other possible solution? Any suggestions as to what I can check?

You could try running the orange and green 12v leads coming from the control head direct to the battery or whereever you have hooked up the heavy gauge red power cable that comes from the drawer connection.

Maratracs are fussy if there is any voltage differential among those three leads so its best just to give them all the same 12vdc source.

It specifacally states this in the Installation manual, and on a sticker on the radio 'drawer' top cover.

The Green lead MUST be tied DIRECT to the battery along with the big RED cable.

Radio is best grounded with the BLK cable to car/truck at or near the drawer.

Oh, there are two mods for this, voltage difference, problem.

In addition to the above, you could also have:

A corroded section of B+ (red) wire either at a butt connecter or cable nick, allowing water in to eat the wire practically into. A voltage check at the B+ contact inside the radio on transmit will confirm this. A noticeable drop on TX indicates a problem. Also check for a resistive fuse and/or fuseholder.

You said you've checked the antenna, but did you check the coax? It may have gotten crushed or cut.

Thanks to all for the advice.

Unfortunately, running the green/orange leads and connecting them directly to the battery did not make any difference at all. So, apparently it wasn't a voltage differential issue between the control head and the drawer.

I double checked the main wire to the drawer and it's in good shape. In fact, it's new and has no signs of wear or corrosion. I checked all the butt connectors, too.

I did check the coax as well. Both the antenna and coax are fine.

It must be a problem in the car's charging system. It seems that's the only thing it could be since I've checked just about everything else. What's odd is that despite a weak battery and/or alternator (if that indeed is the case) the starter still turns over just fine. One would expect that if it can turn over the starter it can certainly power a radio. I don't currently have the equipment with me to test the battery/alternator but will try that next.

Does anyone have any other suggestions?

I've installed quite a few Maratracs and have never ran into this problem before.

Thanks again to all who have posted.

Check the voltage right at the radio upon tx.
Run it into a dummy load.

There are some tweakers in the PA section for trimming the power etc, if someone has been messing with them, it will do goofy things. ( I know, as I tried to turn the power down on a VHF unit).
To adjust them, you need a manual so you can see what is going on.