[App_rpt-users] squelch tail

[Scott Weis]

>
> Hi Scott,
>
> There could be a couple of things that could cause this:
>
> 1. COR always asserted from the radio, and carrier detect depending on
> CTCSS decode only. Check for signal swing on the COR line with a
> voltmeter or a scope and make sure it swings below 0.3V and above 3V for
> signal and no signal conditions.
>
COR no signal +12v, COR w/signal 0.0v usbradio.conf = carrierfrom=usbinvert

>
> 2. There have been reports that when external COR is used with internal
> DSP CTCSS decode, that the system doesn't respond as quickly as when DSP
> is used for both CTCSS and squelch, or when an external decoder is used
> for both CTCSS and the radio's squelch circuit is used. None of this is
> confirmed so if you could confirm it, that would be useful.
>
As a test I have done:  External COR w/o PL (either internal or external) = 
Short Sq tail, External COR w/external PL = no sq tail, DSP COR and DSP PL = 
Really long Sq tail. ( I have radio tune rxsquelch set to 900 and RSSI is 
716).

I have noticed that when I do a radio tune rxnoise and I use DSP ctcss I 
get:
WARNING: Insufficient high frequency noise from receiver.
WARNING: Rx input point may be de-emphasized and not flat.
         usbradio.conf setting of 'carrierfrom=dsp' not recommended.
but when I have ctcssfrom=no it does not give the warning.

> As a test, try using external COR and CTCSS or a combined signal and see
> if that  eliminates the squelch tail.
>
> Steve
> WA6ZFT
>
>