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Is there any GMRS radio that lets you filter out one particular tone on a channel?


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Posted

I'd like to be able to tune to general channel say 16 and not hear one particular tone's traffic. Is there a GMRS radio that lets you do that?

I know my 935G will let me filter out all but one tone, to hear only a particular tone or even a particular other radio id, but I want to filter out one particular tone and hear all others.

Posted
5 minutes ago, 73blazer said:

I'd like to be able to tune to general channel say 16 and not hear one particular tone's traffic. Is there a GMRS radio that lets you do that?

I know my 935G will let me filter out all but one tone, to hear only a particular tone or even a particular other radio id, but I want to filter out one particular tone and hear all others.

I’m not an authoritative source but I haven’t seen any GMRS radios that allow blocking a single tone. 
But apparently some scanners do allow a tone lockout:

https://forums.radioreference.com/threads/sds-how-to-block-specific-dcs-ctcss-from-non-tone-protected-channel.414445/

Posted

Not sure.  I know some years back, Kenwood made a dual band (VHF/UHF) mobile for ham that had a feature similar to what you describe.  I think it was the TMV71A.  I had one and I believe the feature was called "Reverse PL" or similar.  I played with it out of curiosity but was underwhelmed by its performance in actual use.  You could set it to "silence" a repeater using say, a 162.2 Hz tone, but it wasn't completely silenced, as I recall.  The station transmitting the tone selected for "silencing" would occasionally open the squelch for brief periods of time.  It did not offer the quiet that a properly-working PL or DPL does against a station not transmitting the selected PL or DPL did.

In other words, with my specimen, the technology had not yet been perfected.

Posted
1 hour ago, RayP said:

Not sure.  I know some years back, Kenwood made a dual band (VHF/UHF) mobile for ham that had a feature similar to what you describe.  I think it was the TMV71A.  I had one and I believe the feature was called "Reverse PL" or similar.  I played with it out of curiosity but was underwhelmed by its performance in actual use.  You could set it to "silence" a repeater using say, a 162.2 Hz tone, but it wasn't completely silenced, as I recall.  The station transmitting the tone selected for "silencing" would occasionally open the squelch for brief periods of time.  It did not offer the quiet that a properly-working PL or DPL does against a station not transmitting the selected PL or DPL did.

In other words, with my specimen, the technology had not yet been perfected.

It probably never could be perfected. With one PL tone locked out and hundreds others potentially being used, whenever one of the other tones is present, squelch is opened, allowing the strongest station to be heard. 

Posted

Yes, actually, but you need to be handy with a soldering iron and understand the guys of your radio.

There are boards that are designed to decode PL and then pass audio to the speaker if it hears the correct tone.  These were from way back when radios used reeds and other forms of PL decoding and encoding.  But if you had one of those boards and inverted the output so it would MUTE the speaker on a certain tone and allow all other audio to pass, it technically could be done. 

 

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