Pl tone

[rmquinn3419]

What is a Pl tone?

 

[SAR923]

See a good explanation at http://www.radioreference.com/wiki/index.php/CTCSS . This is part of the RadioReference Wiki and contains many answers for new scanner owners.

 

[LarrySC]

PL tone is a squelch lock. If 3 fire depts are in a triangle from your location on the same frefq you would hear all three. If you PGM freq and PL tone for the one you want to hear, then you will not hear the other 2. Short answer.

 

[nexus]

To further back up what others have said, PL is a Motorola trademark name meaning PRIVATE LINE. PL is the same as CTCSS. Just a different term used in motorola radio gear.

CTCSS (Continuous Tone Coded Squelch System) are subaudible tones which transmit at the same time as when you key the radio's PTT (push to talk) button. When a radio like a scanner has CTCSS enabled and has one of the 38 tones assigned to a frequency it will remain muted UNTIL a radio on that same frequncy using the same tone as the receiever transmits. When it trasmits it opens up the reciever to hear the transmission...

FIRE STATION 1 is on Freq: 154.4000 mHz CSQ (carrier Squelch - i.e. no tone)
FIRE STATION 2 is on Freq: 154.4000 mHz PL tone 100.0kHz

MOBILE 3 is using 154.4000 mHz with PL tone 100kHz.

If FIRE STATION 1 tries to call MOBILE 3, MOBILE 3 won't be able to hear FIRE STATION 1's transmission because FIRE STATION 1 is not using PL tones. But if FIRE STATION 2 transmits MOBILE 3 and FIRE STATION 1 will both hear FIRE STATION 2's transmission.

If FIRE STATION 1 was using PL tone 127.3kHz then FIRE STATION 1 would never hear either MOBILE 3 or FIRE STATION 2 because even though they're all three on the same frequency they're on DIFFERENT PL tones.

Try this link too...
http://www.eecis.udel.edu/~dra/pl.html

 

[USAPatriot]

Question then...other than for excluding unwanted transmissions, is there any point in programming the tones in? -Rod-

 

[RyltnVFD]

PL tone is a squelch lock. If 3 fire depts are in a triangle from your location on the same frefq you would hear all three. If you PGM freq and PL tone for the one you want to hear, then you will not hear the other 2. Short answer.

...Unless your county's fire dispatch constantly complains about skip traffic, but is too stubborn/stupid/cheap to implement a tone.

But anyway, no, other than eliminating unwanted traffic, there is really no other reason to program a tone in.

 

[nexus]

Question then...other than for excluding unwanted transmissions, is there any point in programming the tones in? -Rod-

Nope. No other reason or purpose. It's sole job is to seperate unwanted signals you're not interested in hearing.

 

[Voyager]

Nope. No other reason or purpose. It's sole job is to seperate unwanted signals you're not interested in hearing.

Well, it also eliminates squelch tails.

Joe M.

 

[nexus]

Well, it also eliminates squelch tails.

Joe M.

Not all radios will do that. I think it depends on the sensitivity. Just about all of my amateur radios still have a tail at the end of a transmission, even with ctcss invoked. One of my handheld scanners which does not have CTCSS seems to eliminate the tail.

 

[BaLa]

since his post has been answered, and I do not want to make a thread with the same subject.


How would one go about finding out if a PL tone is used and if so what it is.

 

[Joseph11]

Most scanners have PL search functions. For example: If I sit on a frequency and switch my PRO-92 into "PL" mode, when someone keys-up, I'll get the PL tone they're using in about 1 second (provided they transmitted long enough).

BTW, PL tones are in Hertz (Hz), not Kilohertz (kHz).

 

[jmp883]

Question then...other than for excluding unwanted transmissions, is there any point in programming the tones in? -Rod-

Once you go PL/CTCSS you'll never go back!!:twisted:

 

[ILbandit]

Once you go PL/CTCSS you'll never go back!!:twisted:

I agree!
A reason that I love them is....
I used to moniter a customer in Chicago that I frequented, they use low power FM walkie talkie type transmitters to talk to each other inside the chemical plant. But the local police were on the exact same frequency It was hard to moniter the workers in the plant, because the police were constantly talking and covering up all of the guys transmissions on my scanner. I set it to PL mode, got their Tone, programed it in, and didn't ever hear the police again. Blocked everything out except the guys in the plant ONLY.

Works great!!

 

[BaLa]

Most scanners have PL search functions. For example: If I sit on a frequency and switch my PRO-92 into "PL" mode, when someone keys-up, I'll get the PL tone they're using in about 1 second (provided they transmitted long enough).

BTW, PL tones are in Hertz (Hz), not Kilohertz (kHz).

so If I dont have one of 'those' scanners

I'm SOL?

 

[drew6553]

yea maybe unless you upgrade and get a pro 97 to go with your 95 and 83 i know the 97 has a ctcss mode setting in the banks

 

[BaLa]

yea maybe unless you upgrade and get a pro 97 to go with your 95 and 83 i know the 97 has a ctcss mode setting in the banks

waiting to win the lottery, so I can get the 396T.. :lol:
saving money for it..
also waiting how the 'silk screen stuff turns out'

 

[loumaag]

Once you go PL/CTCSS you'll never go back!!:twisted:

I also agree, this is why I don't own a Pro-95. I thought it was a step backward in technology from previous trunking scanners by RS.

...If I sit on a frequency and switch my PRO-92 into "PL" mode, when someone keys-up, I'll get the PL tone they're using in about 1 second (provided they transmitted long enough).

Hmm, mine take less time than it takes for the person to start speaking, it is instant in all my Pro-92/2067 radios.

 

[MacombMonitor]

Also, if you're monitoring more than one system on a given frequency, enabling CTCSS code for each system can help you identify which system you're hearing.


i.e.;

155.0100 MHz Tone: 100.0 Local Police
155.0100 MHz Tone: 131.8 EMS
155.0100 MHz Tone: 107.2 Local Gov

 

[MacombMonitor]

One thing to point out. Depending on which scanner, enabling CTCSS will change the display on your scanner. On my PRO-96, for an analog system, if you have CTCSS disabled, you will see the name of the bank on the display. If you enable CTCSS, it shows the CTCSS tone, in place of the bank name.

 

[Al42]

I used to moniter a customer in Chicago that I frequented, they use low power FM walkie talkie type transmitters to talk to each other inside the chemical plant. But the local police were on the exact same frequency It was hard to moniter the workers in the plant, because the police were constantly talking and covering up all of the guys transmissions on my scanner. I set it to PL mode, got their Tone, programed it in, and didn't ever hear the police again. Blocked everything out except the guys in the plant ONLY.

If the police are transmitting, they're still "covering up all of the guys transmissions on my scanner" - you just don't hear it.

PL doesn't gain you anything - it loses you transmissions on which the PL isn't decodable.