Batboard

Hello,
I have a Pyramid repeater set up to crossband a cdm1250 uhf radio to a low band radio. Whenever I key up a uhf portable the pyramid keys up the lowband to transmit but when I stop transmiting the low band radio locks up and wont stop transmiting, I have to shut the radio down. It works fine when the pyramid is shut off. I'm guesing somethings wrong with the pyramid.

Any ideas?

What type of low band radio are you useing?

Try placing the low band radio on a dummy load and see if the same condition exists. If it operates properly on the dummy load you may have RF from the low band radio getting into the Pyramid repeater.

I would bet it is either what Sparks said, or it is the logic level from the pyramid not playing nice with the CDM's PTT circuit.

Pyramids interface with CDMs fine, I did a bunch of them a while back.

Sounds like lowband RF getting into the pyramid,like usual,lowband gets into everything! Try tuning the lowband antenna for a near perfect match....the dummy load might be a good test.
Also could be that the lowband radio has a harmonic at the Pyramids input freq.
mod