WFM Mono clean, WFM Stereo Lots of static

[mcgu...@att.net]

N00bie running gqrx
OS: Pentoo v3.15.5 (in VMFusion v7.1 VM on MacBook Pro)
gr-osmosdr 0.1.4 (0.1.4)
gnuradio 3.7.5.1
SDR: NooElec R820T (RTL2838U)
Device Info
Using device #0 Realtek RTL2838UHIDIR SN: 00000001
Found Rafael Micro R820T tuner
Exact sample rate is: 1500000.014901 Hz

Listening to FM channels, Receiver Options:  WFM Mono is clean, selecting WFM Stereo has lots of static.    Re-positiioning antenna has very little effect.     Any suggestions for fixing this would be greatly appreciated.

thanks

[Alexandru Csete]

Stereo FM requires higher signal to noise ratio than mono FM, so if
the signal is not strong enough it will sound noisy. Moreover, stereo
FM requires more CPU so it could also be CPU load; however, that would
cause "choppy" sounds rather than continuous noise.

Alex

[Douglas Almquist]

This is puzzling to me too.  I have a MacBook Air with a Corei7 with 4 cores.  I don't see significant cpu usage.  On my desktop machine with a less powerful processor yet the same USB dongle (rtl-sdr RT2832U), I don't get this.  I suspect either a software implementation or noise from the laptop.   Given I too can move the antenna around and see no significant change in static, I'm thinking it's a software problem.  With SDR# on Windows 7, I get much improved sound quality.  If it were a noise issue, I think changing antenna config would radically impact noise/interference etc....