Question about PL about tones

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cram33

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I programmed my frequencies and PL tones for the towns in my area. I got them from the RR database. I see the same frequency being used by more than one town, but with different PL tones. Then I also see different frequencies being used by neighboring towns, but with the same PL tones. Is this right.

I find I am picking up my town's FD, but have yet to pick up any PD.

I thought all the PL tones would be different so town A doesn't get put on town B's frequencies because of the same PL.

Lil' enlightenment please?
 

n2mdk

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What systems are you talking about, this info would help. Pl just help keep different users using the same frequency from hearing each other. If the frequencies are different the PL used doesn't really matter. If they use the same PL they just might want to be able to contact each other.
 

cram33

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n2mdk said:
Pl just help keep different users using the same frequency from hearing each other. If the frequencies are different the PL used doesn't really matter. If they use the same PL they just might want to be able to contact each other.
I live in Oakland NJ (a borough of Bergen County) There are many towns around me (Franklin Lakes, Wyckoff, Midland Park, Ramsey, Mahwah) all within a few miles. Especiallly for mutual aid I am sure they want to talk to each other somewhat.

I am using a BC898T and this area is convential.

Example 1: Wyckoff Police is 158.7300 123.0. But nearby Glenrock Police is 158.7300 167.9. Unless I misunderstand any police agency in those 2 towns using CTCSS 123.0 and 167.9 will both be out on the same frequency.

Example 2: In my town of Oakland I have 2 police frequencies 45.56000 and 45.98000. But the both have PL 100.0. How do you send different depts. to different frequencies if you have one PL?
 

n2mdk

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In Example 1 the PL simply keep the Depts from hearing each other's transmissions. The biggest problem you have it that if one dept is transmitting and if the other one keys up at the same time they can still interfere with each other. The PL only keeps the squelch closed, if it's already open the 2 transmissions can interfere with each other.
In Example 2 the PL is irrelevant really each frequency is seperate they use whichever frequency they use for whatever reason.
 

cram33

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n2mdk said:
In Example 1 the PL simply keep the Depts from hearing each other's transmissions. The biggest problem you have it that if one dept is transmitting and if the other one keys up at the same time they can still interfere with each other. The PL only keeps the squelch closed, if it's already open the 2 transmissions can interfere with each other.
In Example 2 the PL is irrelevant really each frequency is seperate they use whichever frequency they use for whatever reason.

Aaaaahhhhh. Thanks.
 

af5rn

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Are the systems on repeaters? Do they share repeaters, or are there separate repeaters? Sometimes you'll see different PLs on the same frequency in order to control which repeater you bring up. Everybody can still hear each other, because they won't have PL on receive. It's kind of like a poor man's voting system. Just a possibility.
 

firetaz834

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Thought I would throw in my 2 cents worth. Any frequency is a shared frequency that is used by any licenscee that the FCC assigns to that frequency. So, you use PL tones to only let your users hear transmission directed to them. It also help the user from drowning out all transmissions and missing ones specifically for them.

Usually when multiple departments operate on different frequencies and need to talk with each other you would have a mutual aid frequency, in Fire we use the DNR (Department of Natural Resources) as a common mutual aid frequency. In police departments it might be call a TAC (Tactical Frequency). This way in a major emergency all department would switch to that frequency to talk with each other. That channel might not have any pl on it so even if departmens had there own PL tone they would still be able to talk with each other.

I hope this helps some.
 

cram33

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af5rn said:
Are the systems on repeaters? Do they share repeaters, or are there separate repeaters? Sometimes you'll see different PLs on the same frequency in order to control which repeater you bring up. Everybody can still hear each other, because they won't have PL on receive. It's kind of like a poor man's voting system. Just a possibility.
The Frequency is listed as RM. Does that mean Repeater and Conventional?

The fog is slowly lifting. I don't have a firm grasp yet but I understand what I am learning. The important thing is I do have my scanner programmed properly and I won't woory about some channels not picking things up right away. I do have several Tactical channels programmed for Paramus, and didn't know what they were for till now.

Thanks all.

I'll have more questi0ons soon enough.
 
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