Squelch in CW-U Mode


Gedas
 

Simon, is it possible to add squelch control while in CW-U mode like we can in AM/SSB? Would be very handy while making very long recordings and no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.


Simon Brown
 

Ah,

I would have to think about that. The AM/SSB squelch is actually voice activity detection, CW would have to be different.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Gedas via groups.io <w8bya@...>
Sent: 28 December 2022 17:20
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: [SDR-Radio] Squelch in CW-U Mode
 
Simon, is it possible to add squelch control while in CW-U mode like we
can in AM/SSB? Would be very handy while making very long recordings and
no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.








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Gedas
 

RRR. Many of us use CW-U down at VLF to detect signals like MSK or FSK or sometimes just carriers coming on and off. Rarely is it true morse CW way down low. If you could it would be awesome and a good handful of folks would put it to quick use. TU for thinking about it.  73

Gedas, W8BYA EN70JT Gallery at http://w8bya.com Light travels faster than sound.... This is why some people appear bright until you hear them speak.
On 12/28/2022 12:25 PM, Simon Brown wrote:

Ah,

I would have to think about that. The AM/SSB squelch is actually voice activity detection, CW would have to be different.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Gedas via groups.io <w8bya@...>
Sent: 28 December 2022 17:20
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: [SDR-Radio] Squelch in CW-U Mode
 
Simon, is it possible to add squelch control while in CW-U mode like we
can in AM/SSB? Would be very handy while making very long recordings and
no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.








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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


jdow
 

That would be an interesting problem. You'd have to increase latency to make CW detection work. Presume the speed is from some low speed 5 WPM for hams up to 30 WPM or more for commercial. If a carrier appears and vanishes often enough to be CW then open the squelch and play the audio buffered during the diagnosis process. The latency would be huge. But I bet the detection could be made pretty good.


On the other paw, I suspect what Gedas wants is best done with a simple carrier squelch that requires maybe a half second of signal with the associated audio buffering.


{^_^}


On 20221228 09:25:08, Simon Brown wrote:

Ah,

I would have to think about that. The AM/SSB squelch is actually voice activity detection, CW would have to be different.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Gedas via groups.io <w8bya@...>
Sent: 28 December 2022 17:20
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: [SDR-Radio] Squelch in CW-U Mode
 
Simon, is it possible to add squelch control while in CW-U mode like we
can in AM/SSB? Would be very handy while making very long recordings and
no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.








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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Simon Brown
 

Maybe a LMS (Least Mean Squares) notch filter in reverse ?


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of jdow via groups.io <jdow@...>
Sent: 28 December 2022 19:14
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] Squelch in CW-U Mode
 

That would be an interesting problem. You'd have to increase latency to make CW detection work. Presume the speed is from some low speed 5 WPM for hams up to 30 WPM or more for commercial. If a carrier appears and vanishes often enough to be CW then open the squelch and play the audio buffered during the diagnosis process. The latency would be huge. But I bet the detection could be made pretty good.


On the other paw, I suspect what Gedas wants is best done with a simple carrier squelch that requires maybe a half second of signal with the associated audio buffering.


{^_^}


On 20221228 09:25:08, Simon Brown wrote:
Ah,

I would have to think about that. The AM/SSB squelch is actually voice activity detection, CW would have to be different.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Gedas via groups.io <w8bya@...>
Sent: 28 December 2022 17:20
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: [SDR-Radio] Squelch in CW-U Mode
 
Simon, is it possible to add squelch control while in CW-U mode like we
can in AM/SSB? Would be very handy while making very long recordings and
no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.








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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.

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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


jdow
 

Maybe - my first go at it would simply look at the output of the AGC system with enough delay in the signal path between AGC pick-off point to audio path mute function that it seems to happen presciently. Once that works, optimize it with clever technology. For initial function even something that works poorly would be better than nothing.


(I know that intellectually. But actually doing that feels horridly cringe worthy. The danger of doing it that way is being a bit ADHD in your head. Then half way there and working is a HUGE barrier to get over when you should complete the project.)


{o.o}


On 20221228 11:45:50, Simon Brown wrote:

Maybe a LMS (Least Mean Squares) notch filter in reverse ?

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of jdow via groups.io <jdow@...>
Sent: 28 December 2022 19:14
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] Squelch in CW-U Mode
 

That would be an interesting problem. You'd have to increase latency to make CW detection work. Presume the speed is from some low speed 5 WPM for hams up to 30 WPM or more for commercial. If a carrier appears and vanishes often enough to be CW then open the squelch and play the audio buffered during the diagnosis process. The latency would be huge. But I bet the detection could be made pretty good.


On the other paw, I suspect what Gedas wants is best done with a simple carrier squelch that requires maybe a half second of signal with the associated audio buffering.


{^_^}


On 20221228 09:25:08, Simon Brown wrote:
Ah,

I would have to think about that. The AM/SSB squelch is actually voice activity detection, CW would have to be different.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Gedas via groups.io <w8bya@...>
Sent: 28 December 2022 17:20
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: [SDR-Radio] Squelch in CW-U Mode
 
Simon, is it possible to add squelch control while in CW-U mode like we
can in AM/SSB? Would be very handy while making very long recordings and
no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.








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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.

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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Simon Brown
 

LMS is a good concept though, quite easy to see whether there's a carrier. No doubt much better options, just need to think about it.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of jdow via groups.io <jdow@...>
Sent: 28 December 2022 21:10
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] Squelch in CW-U Mode
 

Maybe - my first go at it would simply look at the output of the AGC system with enough delay in the signal path between AGC pick-off point to audio path mute function that it seems to happen presciently. Once that works, optimize it with clever technology. For initial function even something that works poorly would be better than nothing.


(I know that intellectually. But actually doing that feels horridly cringe worthy. The danger of doing it that way is being a bit ADHD in your head. Then half way there and working is a HUGE barrier to get over when you should complete the project.)


{o.o}


On 20221228 11:45:50, Simon Brown wrote:
Maybe a LMS (Least Mean Squares) notch filter in reverse ?

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of jdow via groups.io <jdow@...>
Sent: 28 December 2022 19:14
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] Squelch in CW-U Mode
 

That would be an interesting problem. You'd have to increase latency to make CW detection work. Presume the speed is from some low speed 5 WPM for hams up to 30 WPM or more for commercial. If a carrier appears and vanishes often enough to be CW then open the squelch and play the audio buffered during the diagnosis process. The latency would be huge. But I bet the detection could be made pretty good.


On the other paw, I suspect what Gedas wants is best done with a simple carrier squelch that requires maybe a half second of signal with the associated audio buffering.


{^_^}


On 20221228 09:25:08, Simon Brown wrote:
Ah,

I would have to think about that. The AM/SSB squelch is actually voice activity detection, CW would have to be different.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Gedas via groups.io <w8bya@...>
Sent: 28 December 2022 17:20
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: [SDR-Radio] Squelch in CW-U Mode
 
Simon, is it possible to add squelch control while in CW-U mode like we
can in AM/SSB? Would be very handy while making very long recordings and
no signals present. 73

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.








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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.

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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.

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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.