PL/DPL question

[LIScanner101]

Sorry, I’m getting back into this after a while and I forgot how this works:

If I program a frequency into a scanner with either a PL or DPL code I understand that, unless a Tx with that exact code is being received the Tx won’t break squelch.

But what if I receive a Tx on that frequency with NO code? Will it still break squelch? I think it will, I just don’t remember for sure…..thanks.

 

[RoninJoliet]

Yup, if no PL/DPL anyone using the freqy can be received, even intermod and interference so its best to use the PL.....

 

[LIScanner101]

Yup, if no PL/DPL anyone using the freqy can be received, even intermod and interference so its best to use the PL.....

Great, that's what I thought, thanks for the confirmation. I want to plug-in some low-band CHP frequencies, here's an example:

39.14 162.2PL
39.14 CSQ
39.42 CSQ
39.92 107.2PL
39.92 CSQ

So, in this case I would ONLY program-in the frequencies with PLs with the exception of 39.42 because there's isn't another corresponding license that has a tone with that frequency. Is this right?

 

[GTR8000]

If you program a PL/DPL for a given frequency, squelch will only open if a matching PL/DPL is received. CSQ transmissions and transmissions with non-matching PL/DPL will be ignored, squelch will not open.

If you intend on monitoring any frequencies that use a combination of PL tones, and/or a combination of PL and CSQ, do not programming a PL if you want to hear all transmissions on that frequency.

 

[LIScanner101]

If you program a PL/DPL for a given frequency, squelch will only open if a matching PL/DPL is received. CSQ transmissions and transmissions with non-matching PL/DPL will be ignored, squelch will not open.

If you intend on monitoring any frequencies that use a combination of PL tones, and/or a combination of PL and CSQ, do not programming a PL if you want to hear all transmissions on that frequency.

OK, now I understand. If I program in a PL/DPL and someone comes on the air WITHOUT a PL/DPL tone I won't hear them (I already know that a non-matching tone won't be heard). Thanks for the clarification.

 

[n5ims]

Generally for scanner listeners, unless you have a specific reason for programming in a PL/DPL it's often best to not program it in. The reason is the tone is used to restrict what you hear, and generally you'll probably want to hear everything. It also takes time for your scanner to decode the tone, so if one is programmed in you may miss part of the transmission, especially if the signal is weak.

 

[ab3a]

Since we're nearing peak sunspot time and the frequencies being discussed are on Low Band VHF, allow me to point out that skip is quite possible. You may not want to listen to that skip because it would just confuse you. For example, a fire company 500 miles away may not be what you really wanted to hear. Configuring PL in your scanner can keep that stuff out of the squelch.

Unfortunately, the skip is still on channel. It it will interfere with whatever signals are there, so you may still have trouble hearing what you want. But there isn't much you can do about that.

 

[INDY72]

Also to clarify on the CTCSS/CDCSS decode speed comment: The newer generation of scanners have nearly instant decode rates, just as fast as commercial radio gear. That issue has long been solved. The only times that real issues come up on VHF anymore is with Low Band skip, and High Band ducting. Also remember that if you use the CTCSS/CDCSS codes on freqs in your scanner, and it is in OPEN modes, then you will still get interference to a point. In CLOSED modes this keeps you from HEARING even that litte amount except in certian instances. Older models have a lot more issues than the newer ones, so if your running say a PRO-92 or earlier era scanner, your far more likely to get interferences than say a PSR-800, HP-1, BCD996XT etc.....