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charlie-foxtrot / RTLSDR-Airband

Multichannel AM/NFM demodulator
GNU General Public License v3.0
758 stars 135 forks source link

Squelch bug? #84

Closed spotter-ssol closed 6 years ago

spotter-ssol commented 6 years ago

I've got this strange behavior regarding manual squelch levels: image host Even after the end of transmission and manual squelch level up to 4x the noise floor, audio keeps streaming indefinitely. This is how it look like in Audacity: image host After some testing I've discovered that this behavior only occurs when compiled without NFM support.

szpajder commented 6 years ago

Yep, it's broken. Check out the current unstable branch - should be OK now.

spotter-ssol commented 6 years ago

Solved! Thanks!

spotter-ssol commented 6 years ago

Today I was testing some configs and got the same behaviour, but now in scan mode. Maybe the same bug on another portion of code related to scan? image host

szpajder commented 6 years ago

Do you have any reliable way of reproducing this problem? Does it happen very often?

I've tried several configs, various bands, signal strengths and squelch settings, but it never happened to me so far.

spotter-ssol commented 6 years ago

I did some more testing and discovered that this happens very often (both multichanel and scan) when I set the squelch 3x (or less) the noise floor level. Audio keeps streaming for about 5 to 15 seconds then usually closes itself. When squelch is set 4x or higher this problem virtually disapears.

ghost commented 6 years ago

I have also been experiencing this problem occasionally. It seems like it is most apparent when listening to weak signals, which sometimes dip in and out of the squelch - but it doesn't happen enough for me to reliably confirm this.

szpajder commented 6 years ago

Please check the current code from unstable branch. I have applied a small tweak, and now it should behave better.

spotter-ssol commented 6 years ago

Tested with squelch as low as 2x times the noise floor and no sign of problems. Now I can properly track weak signals. Thank you, sir. I'm having A LOT of fun with this software. Your work is much appreciated!