Batboard

hi I am new to this so bare with me. I have a cdm 750 in my boat that will not tx on one antenna but will on my other. when you key the mic it beeps twice and stops transmitting. it does the same thing with no antenna connected. also i have a maxtrac that when you tx for about a minute or more it beeps and stops. does anyone have any ideas why?

thanks
motoboat

well...

The MaxTrac will stop transmitting after a minute due to a time-out timer, which helps keep the radio's power amplifier from getting fried from continuous transmitting, which causes heat build-up.

As for the CDM mobile, the time-out-timer is clearly not the case. It could be caused by too low ampherage going to the radio, which will cause the radio to transmit a low battery chirp, and stop the radio from transmitting. Odd, but true... the CDM radios have a low battery beep, just like the HT portables.

-Josh

BAD antenna
BAD power source

Did you test radio on a known good dummy load?

thanks josh and will for your help. I think you may be right about the bad power source