RX audio on XPR4500

[johnny1225]

We have a number of Mototrbo Portables with a XPR8300 Repeater UHF Repeater. The hospital is in digital format and radio's and the repeater seem to be working very well. The only concern is they have 1 XPR4500 mobile base station in digital format as well and they do not like the rx audio that is coming from the base. It sounds like you are under water or in a hollow tunnel. I noticed that the antenna is almost overtop of them on the ceiling. Is the antenna to close, should i move the antenna, or is there a programming option in the radio that i can programm to fix this annoying problem. Sometimes they say it sounds like a helicopter, coming in when they are receiving a call only thru the base. Any help would be greatly appreciated.

[wavetar]

I find with the digital radios (both TRBO and NexEdge), lower volume = better sound. The digital sound is naturally more 'bassy', with the high frequency voice (and noise) components not present. If you crank it, it'll quickly sound over driven.

The TRBO radios have digital AGC enabled by default. I have found this can cause the audio issues you describe...you can't set limits on it, so it can 'over drive' the TX audio & make things sound garbled on receive. You can disable AGC and manually set the mic gain until it sounds good when received on the base, but then you run the risk of not sounding as good on the portables.

You should try a good external speaker on the base. A larger speaker will sound louder at a lower volume level, and may solve your issue.

By the way, Motorola will tell you there's nothing to be done about the TRBO audio..."it is what it is". However, Kenwood has introduced 3 different TX filter settings in their later NexEdge firmware, which gives a distinctly different sound with each setting. Motorola could take a lesson from that, as well as to introduce AGC limiting in digital mode, similar to the Astro radios.