FM-Radio: distorted audio, ok with rtl_fm player
Posted: Sat Feb 07, 2026 7:17 pm
Dear Co-Hudiyers,
using a Nooelec, NESDR SMArt v5 rtl-SDR receiver with default settings ("autoGain" : true, "squelchLevel" : 350 and "squelchLimit" : 10) I only get distorted audio via either BT or Soundcard output.
It significantly improves if I reduce the manual gain to below 280 but then end up in instable station search where the revceiver locks to frequencies already 50KHz before or after the 'good' sender frequency (depending on scan direction). I was not successful in fixing this by fine tuning squelch settings: either the lock is 50KHz off or station is not found.
If I operate the stick with 'rtl_fm -f 98.5e6 -s 96000 -E deemp' (default gain:auto, squelch-level=0) I get a cristal clear audio (Hudiy active).
I installed the latest module and libraries including blacklisting unused modules to no avail.
My setup is Hudiy 2.4 (default configuration) on Pi5, Debian Trixie, 3A orig. PI power supply, Audio via: StarTech.com USB 2.0 Soundbox 7.1
using a Nooelec, NESDR SMArt v5 rtl-SDR receiver with default settings ("autoGain" : true, "squelchLevel" : 350 and "squelchLimit" : 10) I only get distorted audio via either BT or Soundcard output.
It significantly improves if I reduce the manual gain to below 280 but then end up in instable station search where the revceiver locks to frequencies already 50KHz before or after the 'good' sender frequency (depending on scan direction). I was not successful in fixing this by fine tuning squelch settings: either the lock is 50KHz off or station is not found.
If I operate the stick with 'rtl_fm -f 98.5e6 -s 96000 -E deemp' (default gain:auto, squelch-level=0) I get a cristal clear audio (Hudiy active).
I installed the latest module and libraries including blacklisting unused modules to no avail.
My setup is Hudiy 2.4 (default configuration) on Pi5, Debian Trixie, 3A orig. PI power supply, Audio via: StarTech.com USB 2.0 Soundbox 7.1