Page 1 of 1

CDM1550LS+ Transmit Problem

Posted: Thu May 08, 2014 10:20 am
by ffnremtwhitby
My CDM1550LS+ VHF radio receives very well, but transmitts very poorly. I have changed antennas with no change. There is a lot of crackling, static, and hum in the receiving radios when this one transmits. Sometimes, if you hold the transmit button for about 20 seconds or so, the problem goes away and transmission clears up. I have swapped mics as well with no change. I have also tried dropping transmission power without improvment as well. Any ideas?

Re: CDM1550LS+ Transmit Problem

Posted: Thu May 08, 2014 11:48 am
by jackhackett
Take the plastic cover off the radio chassis, and check that the bolts that hold the radio together are tight. You'll probably find that they're very loose.

Re: CDM1550LS+ Transmit Problem

Posted: Thu May 08, 2014 12:22 pm
by ffnremtwhitby
That was it. Thanks

Re: CDM1550LS+ Transmit Problem

Posted: Sat May 10, 2014 8:35 am
by mmckenna
Wow, good timing. The CDM1250 in my wife's car was starting to make odd noises on TX. I replaced the mic, checked the power feed, and a few others. Was just about ready to pick up another one. Ran across this post just in time. Tightened the screws and it's working top notch again. Thanks.

Re: CDM1550LS+ Transmit Problem

Posted: Sat May 10, 2014 11:23 am
by Bill_G
Usually it's the loose screw across the microphone, but not today ...

(big grin)

Re: CDM1550LS+ Transmit Problem

Posted: Fri May 23, 2014 12:35 pm
by AEC
I despise that carbon/rubber pad on the CDMs, a loose cover places the radio into 'test' mode.

Re: CDM1550LS+ Transmit Problem

Posted: Fri May 23, 2014 12:39 pm
by mmckenna
Bill_G wrote:Usually it's the loose screw across the microphone, but not today ...

(big grin)


Ah yes, like the "loose nut behind wheel" issue that I see happen with cars.

Re: CDM1550LS+ Transmit Problem

Posted: Fri May 23, 2014 12:53 pm
by Will
mmckenna wrote:Ah yes, like the "loose nut behind wheel" issue that I see happen with cars.


"the loose nut behind the microphone" for radio operators.... ...

Re: CDM1550LS+ Transmit Problem

Posted: Fri May 23, 2014 2:00 pm
by SteveC0625
Will wrote:
mmckenna wrote:Ah yes, like the "loose nut behind wheel" issue that I see happen with cars.


"the loose nut behind the microphone" for radio operators.... ...

The official term is "short between the headphones." :)