Poor WFM and zero NFM Demodulation Audio

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waterman46
Posts: 5
Joined: Thu Oct 15, 2020 11:55 pm

Poor WFM and zero NFM Demodulation Audio

Post by waterman46 » Sat Oct 17, 2020 10:31 pm

I have RTL SDR V3, running SDR#, Windows 10 32bit. SDR# runs normally and I can see WFM and NFM signals in the spectrum. But WFM broadcast audio is very distorted. NFM audio in the 2M ham band is either quiet or sounds like a buzz saw. Maybe heard a slight bit of very distorted human voice once. No filters or noise blanking enabled. Tried all levels of RF gain and there is no difference. Attached pictures.
FM_signal.jpg
FM_signal.jpg (192.54 KiB) Viewed 329 times
2meter_signal.jpg
2meter_signal.jpg (25.19 KiB) Viewed 329 times

rtlsdrblog
Site Admin
Posts: 2784
Joined: Mon Nov 19, 2012 11:54 pm

Re: Poor WFM and zero NFM Demodulation Audio

Post by rtlsdrblog » Tue Oct 20, 2020 4:22 am

Turn on Filter Audio, and reduce the volume on the top volume slider. Max volume is likely to induce audio clipping which would distort the audio. Instead turn up your speakers, or the volume in Windows as well.

waterman46
Posts: 5
Joined: Thu Oct 15, 2020 11:55 pm

Re: Poor WFM and zero NFM Demodulation Audio

Post by waterman46 » Thu Oct 22, 2020 9:56 pm

Got it working on all modes now. I think the problem was the SDR# sound card driver or dll not correctly/completely installed. Deleted and re-installed SDR#. That fixed the NFM issue but caused my PC earphone jack to be dead. So I went back to Windows 10 settings, deleted and re-installed that driver. Earphones came back to life and SDR# NFM works OK at same time.

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