PL tone breaking squelch on an open channel...

[rmassara]

I can't figure out why on 675 my handheld is programmed for 141.3 on rx and tx, but I can talk to my mobile that has 675 open...no pl or dpl enabled. Also, when I tx from my mobile, my handheld will show that it's receiving, but no voice comes across. Anybody else ran into this issue? My mobile is a Midland MXT90, and my handheld is a Baofeng UV-5R (I know it's not legal to use this handheld on gmrs, but all I'm doing is a signal quality check on low power).

[Logan5]

since your mobile is set to open it can hear anything on that channel, even a radio transmitting a PL/DPL, Your HT does not hear your mobile since you have the PL set to 141.3. PL/DPL tones do not provide privacy they only reduce interference from other radio transmissions.,

[rmassara]

Gotcha. Thank you for the clarification.

[quarterwave]

PL/DPL is for channel sharing. It is not for privacy, and is not for interference, as interference would mean you have exclusive use of a channel. Even in commercial use, it is for filtering out unwanted co-channel users, or distant "skip" signals. 

 

As said above, a radio in CSQ hears everything. A radio set to a PL only hears transmissions coded with same PL.

[WRAF213]

Furthermore, when PL/DPL squelch is used, the radio is still listening -- channel-busy indicators (such as the Baofeng's green LED) will indicate to prevent interference to other users; it's just not going to play the audio until it detects the correct receive PL/DPL.

 

CSQ (no PL/DPL receive, just carrier only) completely ignores any PL/DPL received, and plays audio whenever the channel is busy. Since the channel is busy when PL/DPL users are on-channel, CSQ users will hear all activity on a channel, but will only be able to reply to CSQ receivers. Users with PL/DPL receive will be under the impression that the channel is less busy than it actually is, and can easily interfere with other users without being aware that they are causing interference. Additionally, they will (usually) be unaware that they are being interfered with.