Delayed squelch

[MightyPork]

Using squelch on CW and SSB signals results in choppy audio as it keeps muting in the middle of a symbol or word.

An elegant solution would be if the squelch gate remained open some configurable time after the signal level drops below the threshold.

using version 2.16

[willcode]

Gqrx uses the GNU Radio "Simple Squelch" block in the rx nbrx chain. This (and all the GR squelch blocks) has a single alpha value for attack/release, so there's a little work to change the behavior. Might have to make a new block.