Batboard

What could cause a radio to receive multiple call alert tones? This is also intermittent.

All programming dealing with call alert is set up correctly in the subscribers radio. The symptom the user initially gave me led me to believe that the "call alert tone auto reset" was not enabled. After he sent me the codeplug, this was not the case and all call alert settings appear to be correct.

The user has an APX 6500 connected to a relay box, often referred to as a call alert box. This is connected to in station speakers, lights, and gas shut off valves.

The user says that when there is a double set of tones all functions via the relay controller function, but on a single set, the lights and gas won't operate normally, audio passes though along with the audible alert tones but no light control or gas control.

The pages are being sent via MCC 7500 consoles from dispatch using page groups.
All of the page groups are set up correctly.
Any ideas?

My first thought is maybe the audio level deviation might be on the high side and the decoder is having problems decoding a distorted tone.

This goes back to a repeater passing paging tones must not be into compression. This will cause distortion to the tones and might not be decoded correctly.

In many cases the radio techs set up the pass through audio level in a repeater to cause the audio being passed to go into compression. It will take 2 service monitors to make sure this is not the case. One to generate a signal into the repeater and the second to monitor the transmit audio out of the repeater. You don't want the page tones to be at full voice audio deviation. The tones want to be at about 60 percent of the voice level.

Another source of this problems is that if your using a wireline or microwave circuit going to the radio, you need to make sure the audio levels are set correctly. Normally the microwave would be set correctly, but it wouldn't hurt to double check the levels. It could also be a bad leased phone line if that is what you are using.

I sort of have put the horse before the cart here and should have started way back at the dispatch location. It is important to make sure the voice level is correct from the dispatch equipment. Then make sure the page encoder audio levels are again set to about 60 percent of the voice level.

This may not be your problem, but is worth checking. The radio techs that are working on this problem need an audio level meter like a TIMS unit or something that will measure the actual audio levels. Without a meter, your trying to paddle upstream without a paddle. Also make sure they use the meter in the bridged mode and not in the terminate mode. The terminate mode will cause the audio level to be too hot by 3 db when they remove their meter connections.

Let the group here know what you find out. Problems like this are always of interest to everyone.

Jim

Jim,

Thanks for the reply.

Currently the page group being sent via the console consists of "Call Alert" and the audible QC tone. The QC tone is not being sent for any other purpose other than the audio.

Here is a link to what the audio sounds like at the station that is having the issue.

https://drive.google.com/file/d/0B0Gp9M ... sp=sharing