DPL

mainetrunk

Member
Joined
May 29, 2011
Messages
1,552
Location
York county Me.
Hi guys. I know this subject has been discussed, but to me - there's a hole (aka info) I need to get straight.. Long story short - my area got a new vhf - uhf tie, and a lot of New freqs... Some are quiet, while 1 keeps getting accidental transmissions.. I O W , the freq is in the radio of other departments..
Example - a few months back, my fd called dispatch and have a pl of 136.5.
Today a different entity called on it with 192.8....
So, did someone get a different tone in this time, or is this DPL tone in effect?
If so- do I put both tones in, or go with today's catch?
Note --- this freq is not used by anyone near me. External antennas.. Nothing heard, except by accident..
 

mmckenna

I really ♥ Ø
Joined
Jul 27, 2005
Messages
18,054
Location
Pt. Nemo
Repeaters can have multiple tones programmed into them.

In the old days, it was common for radio shops to put up a single channel repeater and have multiple PL tones on it. The shop would rent out access to the repeater to multiple customers. Each customer would have their own PL tone, so their radios would only hear other users on the same tone.

On the public safety side, they may have it set up that way so different agencies can use the repeater and only be heard by their own dispatchers or units. Kind of odd in a way, but that may be what's going on.

Or...

They set up the repeater and discovered it was getting co-channel interference from another one on the same frequency/tone far away. To solve that, they may have changed the tone used to prevent that interference.

Program it into your scanner as carrier squelch only (no PL/DPL tone) and you'll hear everything. If your scanner will display PL tones, it may help shed some light on what's happening.
 

mainetrunk

Member
Joined
May 29, 2011
Messages
1,552
Location
York county Me.
Thanks, I have tone showing scanners, but this isn't a repeater.. It's the former input of pd.. When the repeater fried, they changed the input freq, and left the former input freq.. Why? Unknown... Like I said, it's never used.. I had it on tone search to get 192.8.. 6 months prior the IT used it with a 136.5 tone.. Hmm, I guess I'll leave them both in, and 1 set to search..
Thanks
 

mmckenna

I really ♥ Ø
Joined
Jul 27, 2005
Messages
18,054
Location
Pt. Nemo
Thanks, I have tone showing scanners, but this isn't a repeater.. It's the former input of pd.. When the repeater fried, they changed the input freq, and left the former input freq.. Why? Unknown... Like I said, it's never used.. I had it on tone search to get 192.8.. 6 months prior the IT used it with a 136.5 tone.. Hmm, I guess I'll leave them both in, and 1 set to search..
Thanks
I have some users at work that utilize the same simplex frequency, but have different PL tones. For the little traffic they have, and some physical separation, it works well. For all the end user knows, they have their "own" channel. Setting the radio for "Busy Channel Lockout" will keep them from accidentally keying up over each other on the rare chance they are within range and are using the radios at the same time.
 
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