To Program Tones or Not to Program Tones

[mike_webb59]

I've been messing with my BC246T and CTSS/DCS Search. I know that one can use tones to isolate commonly used frequencies.

Is it possible to "filter" by tones to separate PD/SO from FD/EMS on Public Agency frequencies? I was wondering if it's SOP that the dispatchers used CSQ for regular traffic and then used tones only for FD/EMS, and then if I had identical frequencies, one locked on the tone and one locked out; I can scan for Public Safety on one, and Rescue on the other.

The question is if that process of CSQ/Tones is common in the Conventional Band, or if an agency, *if* it uses tones, uses it for everything.

For example, let's say that there's an entry for Dry Gulch, TX on 155.455, no tones indicated in the RR Database. I plug in CTSS Search, during normal traffic I don't catch a tone and when they dispatch EMS I catch a tone. I copy the frequency and add the tone and call it "Dry Gulch EMS;" and on the remaining copy of the channel I lock out the tone and call it "Dry Gulch SO." Will that work?

Thanks, Mike

 

[pacrat551]

Is it possible to "filter" by tones to separate PD/SO from FD/EMS on Public Agency frequencies?

Yes, provided they are actually using separate PL tones for each agency. Filter = programming the same frequency in differnt channels and adding the appropriate PL tone to each channel

I was wondering if it's SOP that the dispatchers used CSQ for regular traffic and then used tones only for FD/EMS, and then if I had identical frequencies, one locked on the tone and one locked out; I can scan for Public Safety on one, and Rescue on the other. The question is if that process of CSQ/Tones is common in the Conventional Band, or if an agency, *if* it uses tones, uses it for everything.

Typically No. A system will usually have the same PL tone for everybody operating on that particular frequency. This is the reason trunked systems came about, so that multiple agencies can use the same frequencies without talking over each other, or waiting till the frequency is clear.

For example, let's say that there's an entry for Dry Gulch, TX on 155.455, no tones indicated in the RR Database. I plug in CTSS Search, during normal traffic I don't catch a tone and when they dispatch EMS I catch a tone. I copy the frequency and add the tone and call it "Dry Gulch EMS;" and on the remaining copy of the channel I lock out the tone and call it "Dry Gulch SO." Will that work?

Thanks, Mike

Not really, you can't "lock out" a tone. If you leave it CSQ, you will hear everything.

 

[captclint]

I was wondering if it's SOP that the dispatchers used CSQ for regular traffic and then used tones only for FD/EMS

Not typical, but quite possible.

For example, let's say that there's an entry for Dry Gulch, TX on 155.455, no tones indicated in the RR Database.

Don't assume that NO tone in the DB means that there is none. It may be the person that entered it did not bother to list, or had an old scanner that doesn't search PL's

I plug in CTSS Search, during normal traffic I don't catch a tone and when they dispatch EMS I catch a tone. I copy the frequency and add the tone and call it "Dry Gulch EMS;" and on the remaining copy of the channel I lock out the tone and call it "Dry Gulch SO." Will that work?

Yes, this is the best way to handle. Apparently, Aaron answered this while I was writing. Some scanners CAN lock out a PL. This only a problem if you are close enough to another agency that uses that freq and a different tone, OR you pick up skip during the summer months. Best to confirm that there is no tone for the non EMS traffic yourself.

 

[mdulrich]

Not really, you can't "lock out" a tone. If you leave it CSQ, you will hear everything.

At least since the 250D, the Unidens will allow you to lockout a tone.

Mike

 

[pacrat551]

At least since the 250D, the Unidens will allow you to lockout a tone.

Mike

I stand corrected!! Time for me to try out a new Uniden!

 

[kd7rto]

If you are not consistantly seeing the same CTCSS tone, it is possible that what you are monitoring is a frequency used to signal fire pagers.

 

[mike_webb59]

It's a BC246T. I have several area Sheriff's (LCRA Conventional) Agencies in a "Public Safety" System Group that chatter w/no tone, then if they call out the local Fire/EMS, the CTCSS/DCS Search picks up a tone. I note/capture the tone, copy the frequency into a "Fire and Rescue" System Group, add the tone; then use "lockout" for just that tone on the original channel the "Public Safety" System Group.

My scanning preference/plan is to separate PD/SO from FD/EMS. Seems to work.

Also as discussed, I pick up tones that are used all the time; and that will allow me to program duplicate frequencies as I can discern who is talking on that tone.

This was good information. And that feature is really cool.

TX, Mike

 

[crazyboy]

Are you only getting the tones when the ems dispatch has the dispatch tones going or when there is voice for the ems dispatch too? If its just the dispatch tones then they may be falsing you pl decoder. If it shows during the voice, try clearing it right after the tones and see if it reappears.

 

[BirkenVogt]

Here in california, where there are multipe mountaintop repeaters on the same freq, we select which one we want to use by making the radio transmit a different tone for each mountain.

The mountaintop repeaters USUALLY all transmit the same tone, so that everybody's receiver can be protected from interference.

Sometimes, so that the dispatch center can tell who it is that's talking to them, each repeater will transmit the same tone as its input, on its output.

Also, it is possible for a repeater to transmit multiple tones AT THE SAME TIME. Not sure how a tone sniffing scanner would deal with that. This is commonly done on an old system that used non standard tones, being brought up to the standard, and the old tone will also be left on so that the old radios will not need reprogramming.

Birken