PSR-600 DCS Squelch Tail?

[peterjmag]

I recently upgraded to a PSR-600 and am enjoying the radio but I have encountered a problem. Whenever there is a DCS tone used on any analog the radio releases the transmission with this awful squelch tail. I have always had analog only scanners like the PSR-410 which was my last and it never did this on any DCS tones used. Is there a setting in the expert setttings of Win500 that I can adjust to fix this problem? This is disappointing for a $400 dollar radio. Any ideas? Thanks...

 

[DiGiTaLD]

Maybe tighten the squelch up a little bit? Not too much though. I find that this helps with conventional channels on mine.

 

[peterjmag]

Yeah I already tried that and it didn't work. You would think the DSP would allow for a silent release like it does on PL tones but not in this case. Thanks for the reply anyone else have any ideas? Thanks...

 

[W6KRU]

Try reducing the HD5 Fade setting.

 

[peterjmag]

Dan,
I am using Win500 and am in the expert settings and do not see this setting. Can you tell me where it is? Thanks...

 

[SCPD]

under extended settings tab, it is the (fade timeout) setting

 

[W2PMX]

You would think the DSP would allow for a silent release like it does on PL tones

You would - if you didn't understand that reverse burst isn't something you can do with DPL, and it's the reverse burst that kills the audio fast on PL. They could use something else on DPL - maybe a "turn off fast" code at the end of the transmission - but no one does that.

 

[pro92b]

From DCS information at DCS Explained - MMI Technical Resource

The DCS word is sent continuously, starting when transmission begins. When the user releases the PTT, the encoder will change the code to a pattern of alternating 1's and 0's at 268.6 bits per second for 180 milliseconds, then stop transmitting. This "turn off" code causes receiving decoders to mute, thereby eliminating the squelch tail noise burst.

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Adjustment of the HD2 settings may reduce the squelch tail. See the attached PDF.

 

[msingewald]

From DCS information at DCS Explained - MMI Technical Resource

The DCS word is sent continuously, starting when transmission begins. When the user releases the PTT, the encoder will change the code to a pattern of alternating 1's and 0's at 268.6 bits per second for 180 milliseconds, then stop transmitting. This "turn off" code causes receiving decoders to mute, thereby eliminating the squelch tail noise burst.

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Adjustment of the HD2 settings may reduce the squelch tail. See the attached PDF.

I agree. If this didn't exist, how do you explain how the commercial and ham radios can properly decode the DCS/DPL tones? This deficiency has been a real letdown in my use of my PSR-800 (sorry, wrong thread).

 

[peterjmag]

Thank you all for the replies. I'll adjust the radio when I have time and let you all know if it works. Thanks for the PDF that is really helpful. Happy Scanning...

 

[RKG]

Don't overlook that the problem may lie with the system you are trying to monitor, not with your receiver.

The only way to get a "clean" mute on a receiver is for the transmitter to give the receiver a signal that the carrier is about to drop. Traditionally this is done one of two ways: either sending of a "turn off" signal (such as a polarity reverse/phase shift) in PL or the turn off code in DPL) or to have the transmitter keep the carrier up for a time (usually on the order of 150 msec) after sent tone drops.

If the transmitter doesn't send a turn off code (or doesn't send one in a format that a receiver understands) and if it turns off tone and carrier simultaneously, then no receiver in the world will give you a clean mute.