Squelch tail

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mmhorn

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My new TRX-1 seems to have a loud squelch tail on several conventional frequencies. They do not occur on trunked channels. I don't remember them being a problem with my PRO-106. Is there a way/setting to tone them down a bit or eliminate them?
Mike
 

alabamarailfan

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Hello,
Where do you have your squelch set? I had to set mine up to between 8 and 10 on conventional channels to get rid of a loud, long squelch tail. I'm not accustomed to running squelch that high but that seems to be the norm with these Whistlers.

Let us know if this helps!
 

krokus

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My new TRX-1 seems to have a loud squelch tail on several conventional frequencies. They do not occur on trunked channels. I don't remember them being a problem with my PRO-106. Is there a way/setting to tone them down a bit or eliminate them?
Mike

Do the signals you are monitoring have CTCSS or DCS? If so, using that option on the scanner should eliminate the squelch tail.

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Ubbe

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When you monitor one of those problematic frequencies, open squelch fully and listen to the noise when the transmission ends. Compare to when you remove and attach the antenna. If the noise change you probably have some interference in the house. It could be a computer, LCD screen, television set, satellite box, network router or many other things.

/Ubbe
 

dispatch235

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I had two different frequencies that exhibited that problem on my Pro 197 and after length search on the RR forums or a google search found that switching the Mod type from fm or nfm to auto would help. All I know is after I did switch the mod setting the squelch "tails" went away...
 

hosehead88

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I had two different frequencies that exhibited that problem on my Pro 197 and after length search on the RR forums or a google search found that switching the Mod type from fm or nfm to auto would help. All I know is after I did switch the mod setting the squelch "tails" went away...

But that will remove the CTCSS from the frequency, correct?

Do the signals you are monitoring have CTCSS or DCS? If so, using that option on the scanner should eliminate the squelch tail.

Sent via Tapatalk

The offending freqs are all CTCSS for me and I get a brutal tail.


Is there a way to set the squelch per frequency on the software?
 

AggieCon

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I recommend lowering the delay time to 0.2 or 0.3 seconds to minimize this problem. Or even turning the delay off completely.

What is the squelch mode setting for the object? Search, none, a specific selective receiving code, etc.?
 

hosehead88

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No, setting the mod type doesn't change your CTCSS settings.

Changing the mode to Auto, for example, actually does automatically change the Squelch to Search, so I have discovered. I will try it, but this doesn't seem to make sense. CTCSS should be sufficient to kill the tail.
 

N8DRC

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Do the signals you are monitoring have CTCSS or DCS? If so, using that option on the scanner should eliminate the squelch tail.

Sent via Tapatalk

It still does it, I have to run the squelch to 12 all other radios I can have just above the noise. TRX 1 & 2 both do it with or with out PL tones.
 

N8DRC

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Hello,
Where do you have your squelch set? I had to set mine up to between 8 and 10 on conventional channels to get rid of a loud, long squelch tail. I'm not accustomed to running squelch that high but that seems to be the norm with these Whistlers.

Let us know if this helps!

Same here
 

Ubbe

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If you remove the antenna and open squelch fully on a CTCSS programmed channel and you still hear noise, it indicates a programming error.

Also, if you remove antenna you'll be able to tell what levels the squelch normally uses. My TRX-2 open SQ at 6 and closes at 8. Normal setting for me is 9 or 10 to cut out those transmission that have too much noise.

/Ubbe
 

hosehead88

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If you remove the antenna and open squelch fully on a CTCSS programmed channel and you still hear noise, it indicates a programming error.

Also, if you remove antenna you'll be able to tell what levels the squelch normally uses. My TRX-2 open SQ at 6 and closes at 8. Normal setting for me is 9 or 10 to cut out those transmission that have too much noise.

/Ubbe

Not a programming error. This is device related. A CTCSS freq should not be doing this...
 

mmhorn

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Resolved

After much trial and error, I discovered that the only way to eliminate/reduce the squelch tail is to reduce the delay on each offending channel. A value of 0.2 seems to work fine. I will try increasing it in increments to find the cut-off point (where the squelch tail becomes obnoxious again). Thanks to everyone for their input and suggestions. By the way, a note to the Whistler tech offered no resolution.
 

Ubbe

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.... the only way to eliminate/reduce the squelch tail is to reduce the delay on each offending channel. A value of 0.2 seems to work fine....

That's what Aggie suggested. If that's the case it is a genuine scanner problem. The scanner knows that the carrier have gone and starts the delay timer but somehow the logic still have the audio path to the speaker open for a much longer time. The FW programcode probably goes astray and "forgets" about muting the audio until another program loop discovers that there's no carrier and mutes.


/Ubbe
 

BrianG61UK

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I'm not understanding why using CTCSS or DCS is expected to remove a "squelch tail".

I would expect that detecting that the CTCSS tone or DCS code has stopped would take much longer than detecting that the carrier level has dropped which should be almost instant.
 

nd5y

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I'm not understanding why using CTCSS or DCS is expected to remove a "squelch tail".

I would expect that detecting that the CTCSS tone or DCS code has stopped would take much longer than detecting that the carrier level has dropped which should be almost instant.
That's what reverse burst is for. If the transmitter sends CTCSS reverse burst or DCS turnoff code then the squelch closes immediately.
I haven't used a Whistler product so I don't know how well they handle CTCSS reverse burst or if they detect it at all.
 

Ubbe

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Whistler uses an audio delay line that delays the audio to the speaker so that the squelch circuit has time to react. There shouldn't be any squelch tail at all with a whistler scanner. The delay can be noticed in the recordings of analog signals without subtones as each one starts with a "phsssht" as you hear the delayed audio prior to the squelch opening.

/Ubbe
 
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