Slow Squelch Close When Using CTCSS

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G7JIQ
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Slow Squelch Close When Using CTCSS

Post by G7JIQ » Wed Jun 23, 2021 11:13 pm

Since the last beta (Jun 13 2021) I have noticed that when using full CTCSS I get an RX squelch tail, which wasn't in the previous version.
It was nice to be able to select Full or TX only CTCSS to ether hear or kill the squelch tail.

This made it really nice to be able to kill the squelch noise when using the radio on an allstar node.

Please can you kill the squelch tail in the next beta version, as this would be most appreciated.

Cheers
Dave G7JIQ

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F1RMB
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Re: Slow Squelch Close When Using CTCSS

Post by F1RMB » Thu Jun 24, 2021 5:20 am

Hi,
G7JIQ wrote:
Wed Jun 23, 2021 11:13 pm
Since the last beta (Jun 13 2021) I have noticed that when using full CTCSS I get an RX squelch tail, which wasn't in the previous version.
It was nice to be able to select Full or TX only CTCSS to ether hear or kill the squelch tail.

This made it really nice to be able to kill the squelch noise when using the radio on an allstar node.

Please can you kill the squelch tail in the next beta version, as this would be most appreciated.

Cheers
Dave G7JIQ
Hmmm, the code regarding the CTCSS tail "grace time" hasn't changed between the last release and Beta. Can you tell me which Eco level you are using ?

EDIT: could you try to reproduce with Eco level set to 0 ?


Cheers
---
Daniel

G7JIQ
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Re: Slow Squelch Close When Using CTCSS

Post by G7JIQ » Thu Jun 24, 2021 9:56 am

Hi Daniel
Thankyou for your reply,

Just to give you an overview of what i have. ( Hope this is of help )

I am using a GD-77 radio with eco mode now set at 0 ( I normaly use 4 ) and squelch set at 50%, and I am still getting a squelch tail.

When listening, it makes no difference to the squelch tail, if the RX CTCSS is on or off, and the CTCSS is working fine, as if I set it incorrectly for my node/gateway, I loose RX audio, ( as expected ).

I have two of the same radios and they are both performing the same,

Apart from the squelch, all of the original and new features work for me with out any problems.

Cheers
Dave G7JIQ

G4EML
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Re: Slow Squelch Close When Using CTCSS

Post by G4EML » Thu Jun 24, 2021 3:54 pm

There is a deliberate delay applied to the CTCSS decoder which can result in hearing short squelch tails.
This is because the decoder in the radio suffers from intermittent CTCSS dropouts with weak signals.
Some users complained about the signal breaking up when using CTCSS, so this delay was added.
If you have updated from an old version of OpenGD77 to the latest release then you may have only just noticed this change but it has been present for some time.

Colin.

G7JIQ
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Re: Slow Squelch Close When Using CTCSS

Post by G7JIQ » Thu Jun 24, 2021 11:57 pm

Hi Colin

When I use full CTCSS on any of my radios when recieving a weak signal I notice that there will be and is usually drop outs as expected as the decoder looses its sync tone.
I normaly just turn off the CTCSS RX off, only leaving the TX on so enabling repeater access, and I find the easiest way is to program two memory channels and swap them as required.

Up till now turning on the RX CTCSS was a great way to get rid or the squelch tail, and for those who like the squelch tail it is simply turned off.
The original software (even tho it was rubbish compaired to now) didn't have a squelch tail.

As for those who complain of drop out, I suggest they read any of the manuals (eg Yeasu or kenwood) as I have seen in past manuals how to set up the radio when drop outs are happening with full CTCSS enabled.

Just a last thought, I wonder who decided to cripple one of the propper use's of the CTCSS for a big number of user versus possibly just a cupple of complainers. ?
Especially when the easiest solution is a quick click of the radios menu to disable it....

Other than that slight annoyance I must commend all involved for all there efforts and time on this excelent project,
Keep up the good work..

Cheers
Dave G7JIQ

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F1RMB
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Re: Slow Squelch Close When Using CTCSS

Post by F1RMB » Fri Jun 25, 2021 9:28 pm

Hi,

So I've checked the current code (I spend few hours on this, today)

The CSS tail was removed/reorganized many months ago (around February).

Currently, there is a grace time, when already receiving, if the CSS is not detected anymore, e.g over-deviation. The recovery time, before the audio amp is disabled, is 150ms max. If that grace time is disabled, under some condition, the audio amp is constantly disabled/enabled, and that's really annoying.

If the signal disappear, the audio Amp is immediately disabled, regardless of the usage of sub-tone/code, so the heard noise is simply happening when the signal is vanishing (noise level vs squelch is measured each 25ms).

Hence, the tail noise is identical using sub-audio/code or not.


Cheers.
---
Daniel

G7JIQ
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Re: Slow Squelch Close When Using CTCSS

Post by G7JIQ » Sun Jun 27, 2021 12:45 pm

Hi Daniel

Thanks for you reply,
What you say in your reply is what I had thought, but I don't know why I have suddenly developed a squelch tail after the last update.

After more testing I have found it more pronounced and noticeable when using my allstar node/hotspot. (this hasn't been touched in months)
I am in the process of building another node for mobile, which should be complete in a few days.
When its up and running I will see if it has any effects on the RX and let you know of the outcome.

Thanks for looking in to this for me.

Cheers
Dave...

G7JIQ
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Re: Slow Squelch Close When Using CTCSS

Post by G7JIQ » Thu Jul 01, 2021 11:31 am

Hi Daniel

Just to give you an update to my squelch problem. (which I have found, but don't fully understand...)

Just to set the scene,
I have two GD-77 radios and two allstar nodes/hotspots,
My nodes are a copy of the shari node & are setup as per the instructions, (they use an SA-818 radio module & are dupicate builds)
Settings are tx & rx ctcss on both the GD-77's and both hot spots, (set at 77hz)

I have found that my older node is giving a squelch tail, and my lastest build is not.
All tests are done in local mode so my problem is not derived by anything online.

After a lot of double checking & head scratching I found out the problem is in the settings of the SA-818 tx/rx module.
Part way through programming the SA-818 module, it askes, CTCSS Reverse Burst Y/N....
It turns out that if set to 'N' you get s a squelch tail, & if set to 'Y' you dont.

The strange thing is I had it set to 'N' since It was built it about 8 months ago, (set as per the instructions) and have been using it with both radios on a daily basis with no problems.
I only found a cure by trial & error,
It turned out it was in programming the SA-818,
I had programmed it so many times, trying different things, fat fingers got in the way & by accident I found it. (by then I was ready to launch it out of an open window)

A really strange fault which was caused by reverse ctcss, whatever that is, (no detailed information from SA-818 datasheet or the shari setup instructions)

Sorry to takeup your time chasing something that wasn't there.
Thanks again for all your work on the project.
A lesson learned.....

Cheers
Dave..

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F1RMB
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Re: Slow Squelch Close When Using CTCSS

Post by F1RMB » Thu Jul 01, 2021 11:44 am

Hi Dave,

Okay. The reverse CTCSS burst was/is a technique to get rid of the tail (https://en.wikipedia.org/wiki/Continuou ... erse_CTCSS), but we don't support it ;)

I didn't waste my time, I've made some slight changes/cleanups in the CTCSS code at the same time :D


Cheers.
---
Daniel

G7JIQ
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Re: Slow Squelch Close When Using CTCSS

Post by G7JIQ » Sat Jul 03, 2021 12:44 am

Hi Daniel

Thanks for your reply, and info link. (interesting reading)

Thanks for all your work on thje project, and I look forward to trying the next update.

Cheers
Dave...

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