ZDC59 Squelch tail

[jaymatt1978]

Is anyone else having a little trouble with a squelch tail 133.1250 ZDC59? I been having trouble on and off but think i got the squelch set properly. I'm using bcd996t's

 

[jaymatt1978]

Just an update only certain planes who transmit on that frequency have the squelch tail. Other planes transmit on that frequency and it's fine, no hangups. This is VERY frustrating!!!!

 

[alcahuete]

757s are notorious for having a "squelch tail" of sorts. I can recognize a 757 on the radio by that alone.

 

[spanky15805]

alcahuete...thought you were going to say RR whine on a 757.

 

[ATCTech]

Is this frequency by chance cross-coupled (radio re-transmit) with another ATC frequency? What you're describing is a classic example of the squelch signal being delayed and holding the one of the cross-coupled transmitters on the air just slightly longer. We do out and back squelch delay tests regularly on our individual frequencies for that very reason as each circuit will exhibit different delay characteristics that can and do change from time to time as TELCOs make minor routing or technology changes. It also explains why only certain aircraft seem to cause it - it's the ATC radio path, not the aircraft. We're talking tens to perhaps one hundred of millisecond delays by the way. Very, very common.