Batboard

We have five MCC5500 dispatch consoles with CDM1250's attached with L3276 tone remote adapters. All the same band radios are programmed the same (cloned). One of the Vhf CDM's has poor quality audio to the consoles. It has static at the end of received audio and sounds overmodulated.When heard on the CDM's own speaker, the audio is fine. Another odd thing, even though the receive sensitivity is good, the signal strength meter doesn't start to register until around 3 uv is punped into the radio. If this CDM is swapped with a good CDM, the problem stays with the bad CDM.
Anyone have any ideas?

Thanks

Joe

JMINN wrote:We have five MCC5500 dispatch consoles with CDM1250's attached with L3276 tone remote adapters. All the same band radios are programmed the same (cloned). One of the Vhf CDM's has poor quality audio to the consoles. It has static at the end of received audio and sounds overmodulated.When heard on the CDM's own speaker, the audio is fine. Another odd thing, even though the receive sensitivity is good, the signal strength meter doesn't start to register until around 3 uv is punped into the radio. If this CDM is swapped with a good CDM, the problem stays with the bad CDM.
Anyone have any ideas?

Thanks

Joe

You need to supply some information on how your connecting the radio to the MCC5500. If your using the rear accessory connector, which pins are you obtaining the RX audio from?

If you go into the radio software in the "Radio Configuration". Go to the "Accessory Configuration" tab. Then go to the "RX Audio Type" line. I would suggest that it be set to "Filtered Audio".

There is the possibility that the radio frequency got programmed wrong slightly putting the receiver off frequency. The other possibility is that the RX audio output got blasted by something in the past. It will take some nosing around to locate the real cause of what your trying to describe.

Jim

All six of out CDM's are connected to the tone remote adapters via the the accy jack. All the cables are identical. All set ups are identical. The radios are cloned. Switching the radios around the problem stays with the radio, the cables, adapters, MCC,all work well with other CDM's. I have reprogrammed the bad one and it made no difference. Also all the CDM's have the same firmware version.

Joe

when you swapped radios betweeen positions, did you reprogram each one to the 'new' spot? or keep it at the original freq.?
Just trying to dub out if it is specific to the frequency?

Joe, I sent you a PM about this issue, as we are experiencing the same issue with all 10 or so of our CDM1250s via tone to the MCC5500.

My suggestion at this point would be to put the radio on a service monitor and make sure the radio is on frequency. Being off frequency can cause distorted audio.

With the distorted audio following the radio, off frequency can cause what your telling us. I would also try to measure the audio level coming out of the radio and going to the remote adapter.

One point that has not been clear, when you said you swapped the radio around. Is the move including the remote adapter or just the adapter? If your moving both, then the problem could be in the way the radio RX audio level is being set in the remote adapter. In this case you will need to measure the radio RX audio level leaving the tone remote adapter that is going to the console. This level being too high will cause audio distortion. You will have to use a service monitor and generate a signal into the radios. Set the signal audio level to about 80% deviation and then measure the line level leaving the tone remote adapter. You should see no more than between a -10 db and a -5 db or so tone level.

Jim

+1 what Jim said.

My read of the thread says the radio is broke - fix radio.

If all the other radios work well with the set up, *and* if the audio problem is fixed by swapping another radio into place, *and* the bad audio radio has bad audio when swapped into any other set up, then the radio needs service.

If you've done an accurate job of describing your process, then you've done your troubleshooting correctly. Send it in, get it done.

I flashed in the latest firmware and it corrected the problem.