Batboard

I'm using a VHF motorola Astro Spectra to monitor local Fire Department operations. For some reason when the Dispatch sends out a tone the radio does not pick it up. It will only pick up the transmission when they announce the call (actual dispatcher talking). Monitor is on so it can't be a PL problem. It's wierd, I'm using a scanner along side of it and it picks up everything. Has anybody heard of this before?

Thanks

If you're working in analong, then probably your department's transmitted Secode tones are not sent with a
PL and the PL cuts in when the dispatcher starts the vocal alarm. I have
the same exact situation with a nearby Maryland county. Saves your having
to listen to all that boop beep crap all day long.

Since it's in monitor that rules out PL. I'm thinking maybe DOS (Data Operated Squelch). What kind of tones are they sending?

Is this fire department using Astro? If so, then the tones are going out in analog and the voice is astro. You probably have the personality set to ASTRO ONLY rather than MIXED MODE.

The tones are sent using analog and the voice is also in analog. It's strange why it won't pick the tones up....

???

Did you read what I wrote above?

It's not a PL problem. I have a scanner set to the PL (which is 136.5) and that picks up both the tone and the voice of the dispatcher. So when they Dispatch a deparment, both the actual department tone and voice is sent with the PL. The Astro Spectra i'm using does have the PL programmed into it but I'm using "MON ON" so it shouldn't matter either way. It's really strange.

Is it two tone signalling or MDC or what?

Are tones always sent before voice on that channel? You can check the RX Unmute Delay setting under RX Options for that channel, maybe the delay is set so it only unmutes after the length of time the tones take.

If that's not it you could try turning off DOS in the MDC settings.. that mutes when it detects MDC signalling so it shouldn't affect two tone, but it couldn't hurt to try.

He said tones. Not MDC.

Thanks guys for all the input. And just to clear it up it is two tone signalling, and all analog transmissions...both the tone before the voice and the actual voice. I brought it back to the radio shop today and I'm gonna have the tech look at it. Probably just a progamming issue. It's like the radio wants to mute out the tones. Oh well, it'll come out in the end. Thanks again!

Here's a hint: be sure your mobile is set for the same channel width as the department's base station. This has to do with how DSPs handle pure tones. There is a long story behind how I discovered this, but I don't have time right now (and it isn't all that interesting anyhow).

RKG wrote:Here's a hint: be sure your mobile is set for the same channel width as the department's base station. This has to do with how DSPs handle pure tones. There is a long story behind how I discovered this, but I don't have time right now (and it isn't all that interesting anyhow).

Hmm... I wouldn't have thought of that (I've been in analog mode too long) but it sure makes sense now that you mention it.

Hey guys...yup we found the problem. The previous owner had the first three channels programmed in narrow band instead of wideband and the radio shop tech didn't catch it the first time he programmed it for my channels. Works perfect now!