Pro- 96 tones

[jgarber311]

Hey guys- I have my Pro 96 programmed for many FD's along with their respective pl or dpl tones. When one of them is toned out I hear the first tone, then only part of the second tone. It is as if during the second tone- it switches pl tones or something. I have a commercial radio with the same tones programmed in as well as several HAM transceivers with the same tones programmed in- but this doesn't happen to them. Why does this happen to the Pro 96?

Thanks!
Jamie KB8TTR

 

[BoxAlarm187]

Hey, not sure why this thread was started in the Canadian forum, but I'll bite. I've had the same exact problem with my Uniden 796D's, so I'm also interested in any theory y'all might have!

 

[jgarber311]

I'm not sure why I put this in the Canadian thread either- or even how I did it! LOL

Sorry

Jamie KB8TTR

 

[mlevin]

While vacationing on the Oter Banks of North Carolina, I also experienced the same thing. However in my area I don't have that problem. I would also be curious as to why the scanner cuts off the tone.

 

[bcradio]

If you're talking about the CTCSS tones, I've noticed our local fire paging system uses multiple tones. The Tone (beeeeep) itself will be tone X, while the voice page is on tone Y. Not sure why that is, but that's what's happening here.

 

[BoxAlarm187]

I have one locality in particular that does it for me. Chesterfield County, VA uses a P-25 800MHz system, but simulcasts it's dispatch traffic and tones out its volunteers on 154.160MHz. However, this is CSQ, so different PL's definately isn't an issue. :?

 

[rdale]

"When one of them is toned out I hear the first tone, then only part of the second tone."

I have the exact same thing... Must be a Pro96 bug, since my Uniden is sitting right next to it, and programmed with the same freq and PL, and gets the entire transmission.

 

[N_Jay]

"When one of them is toned out I hear the first tone, then only part of the second tone."

I have the exact same thing... Must be a Pro96 bug, since my Uniden is sitting right next to it, and programmed with the same freq and PL, and gets the entire transmission.

Sounds like the high modulation paging tone is confusing the PL decoder (or decoding algorithim) in the scanner.

Or it is some funky "feature" designed to keep you from getting blasted by paging tones.

 

[K7TKR]

Are you sure you're hearing PL tones? PL tones are sub-audible which means you can't hear 'em. A lot of departments across the country use DTMF tones for incident paging. Could be some other type of tone paging but not PL tones I think.

 

[N_Jay]

Are you sure you're hearing PL tones? PL tones are sub-audible which means you can't hear 'em. A lot of departments across the country use DTMF tones for incident paging. Could be some other type of tone paging but not PL tones I think.

I think he is talking about paging tones sent with PL, and losing PL during the second tone (therefore muting the receiver)

 

[K7TKR]

I havn't heard of dual PL tones on a single frequency though I suppose it's possible and, I don't know how a PL would interfer with other audible tones. Put the radio into CSQ mode and see what happens while scanning for PL and maybe that would shed some light on the problem.

It's a strange. I don't belive my Pro-96 has experianced this kind of problem.

 

[Voyager]

Hey guys- I have my Pro 96 programmed for many FD's along with their respective pl or dpl tones. When one of them is toned out I hear the first tone, then only part of the second tone. It is as if during the second tone- it switches pl tones or something. I have a commercial radio with the same tones programmed in as well as several HAM transceivers with the same tones programmed in- but this doesn't happen to them. Why does this happen to the Pro 96?

Thanks!
Jamie KB8TTR

Wow. Lots of replies, but few answers. The paging tones are 'talking down' (industry term) the CTCSS or CDCSS tones. It is basically overpowering the decoder and the decoder is losing the tone or code.

It's not happening with voice since there is enough 'low level' time to recover the tone decoding. BUT, if someone were to say "FIIIIIIIIIIVE" (or any long sylable) for a long enough time, I'm sure I would happen then, too.

It doesn't happen on commercial radios, or even most ham radios, because they filter the low end of the audio spectrum before sending that filtered audio (typically below 300 Hz) to the decoder. I've seen this same thing on recent GRE and Uniden models. They must not be filtering the audio before sending it to the decoder. They must be sending all the audio (including voice and tones) to the decoder, and that is causing the problem.

This sympton became worse when decoders switched from reeds to microprocessor decoders, but that's another thread.

There is little you will be able to do to solve the problem until the scanner manufacturers add low pass filters to the audio going to the decoders.

BTW, all commercial radios and many ham radios also high pass filter the audio before sending that to the speaker - removing the audio below 300 Hz. Modern scanners are doing that now, too, but if you ever listen to a conventional transmission on a BC210, for example, you can clearly hear the CTCSS or CDCSS. I think most modern scanners do that for convenience to the user (so you don't hear the hum of CTCSS or warble of CDCSS), but filtering the audio going to the decoder has never been as big an issue.

Joe M.

 

[INDY72]

And for the response aboput multiple PL's on one freq... If for example say county X has multiple repeaters for the entire county's VFD's.... and has them seperated so that they are in different districts assigned to specific repeaters,... then you will find distinct CTCSS/CDCSS for each repeater. The mobiles can be set up to switch tones for interoperability.

Example: Lincoln County
EOC operates on 155.8950 MHz, utilizing TWO repeaters - North Tower, and South Tower, at opposite ends of the county. North Tower has a CTCSS (PL) tone of 203.5, while South Tower has a PL of 173.8.

Hope this helps guys.

 

[K7TKR]

And for the response aboput multiple PL's on one freq... If for example say county X has multiple repeaters for the entire county's VFD's.... and has them seperated so that they are in different districts assigned to specific repeaters,... then you will find distinct CTCSS/CDCSS for each repeater. The mobiles can be set up to switch tones for interoperability.

I just assumed that he was describing a problem with the Pro-96 and a single repeater. I know of an area up in Northwest Arizona where the county sheriff uses several repeaters but one frequency and multiple PLs as you said but, I havn't had the problem he described.

But he also described hearing the tones-which suggests DTMF to me. And if so, might there be a case of the reciver being overwelmed which you suggested I belive.

Maybe one could run the signal through an external filter before the receiver and see what happens.

 

[nmfire10]

I agree with the others... The paging tone is simply pissing off the scanner's PL decoder. There is probably very little you could do to prevent this... it is just the nature of the decoder.

 

[mlevin]

Fascinating!!!!!!

 

[james32746]

Seminole County, FL does the same thing (on it's conventional 154.235 alert tone channel)

Voice and most fire station alert tones are CTCSS-103.5
but a few fire stations their tones are CTCSS-67.0

 

[nmfire10]

Seminole County, FL does the same thing (on it's conventional 154.235 alert tone channel)

Voice and most fire station alert tones are CTCSS-103.5
but a few fire stations their tones are CTCSS-67.0

What the hell are you talking about???

And please, spare us the huge text, it is not neccessary.

 

[BoxAlarm187]

I agree with the others... The paging tone is simply pissing off the scanner's PL decoder. There is probably very little you could do to prevent this... it is just the nature of the decoder.

I'll bite, seems like a good theory. However, what about when it happens on a CSQ frequency? The scanner's not decoding any PL/CTCSS if it's CSQ...

 

[N_Jay]

I agree with the others... The paging tone is simply pissing off the scanner's PL decoder. There is probably very little you could do to prevent this... it is just the nature of the decoder.

I'll bite, seems like a good theory. However, what about when it happens on a CSQ frequency? The scanner's not decoding any PL/CTCSS if it's CSQ...

Did someone say it was happening on a CSQ channel?