Audio Distortion - Cannot Decode FT8

[RoverSDR]

Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I7,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2

Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded. Using SDR Sharp with Airspy R2 and WSJT-X decodes FT8 fine...so the issue does appear to be with V3, likely settings.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation.



Thank You
Mike K7PI

[RoverSDR]

Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I7,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2

Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded. Using SDR Sharp with Airspy R2 and WSJT-X decodes FT8 fine...so the issue does appear to be with V3, likely settings.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation.

[Simon G4ELI]

Hi,

That's very bad signals in the waterfall - turn the gain slider to 10 or 11.

[Max]

There's no issue with SDRC. I use it on FT8 with WSJT-X and it works perfectly.

To me, if no problems in other SDR software, sounds like a VAC routing issue? I didn't think the waterfall on SDRC looks too bad given you are very zoomed in. Not much S/N. Maybe show us band with more activity like 20m?

First things first. You say audio sounds "mushy". Change audio out selection from VAC (VB-Audio) to Speaker (or whatever audio on your soundcard directly feeds your speaker) so you have no VACs in the equation. Now does the audio still sound "mushy". If the audio comes good (audibly), it's a routing issue with VAC. Very easy to get VACs messed up with Windows sounds routing.

73

Max

[RoverSDR]

Thanks Simon and Max for the comments. Simon, I have tried less gain and it has had no impact on the mushy audio. I hear distortion on signals as well via the computer speakers without the virtual cable inline. FM radio is distorted too. I don't see the issue on any other software using the VAC with the Airspy R2. Max, I can't show you a real busy FT8 band as the Airspy R2 only goes down to 24 MHz.

The issue has to be somewhere so I'll keep digging into the settings. I won't give up. The SDRC is a much better way to go. I'll let you know what I find. Thanks again for the help.

Mike K7PI

[RoverSDR]

Sorry, I should also add that the same audio distortion occurs on 6 meter FT8 signals...I just use the 12 meter band to trouble shoot because there are a lot more signals to look at. Thanks

Mike K7PI

[Simon G4ELI]

Sorry, I should also add that the same audio distortion occurs on 6 meter FT8 signals...I just use the 12 meter band to trouble shoot because there are a lot more signals to look at. Thanks

Mike K7PI

Ah - R2. Sadly I don't see your status bar in the screenshots - I must see this. What bandwidth are you using? Please enable the statistics: Ribbon Bar, View, Waterfall Extras, Statistics.

Set the gain to 10, the visual gain to 0.

Trust me - this is not the VAC, it's the quality of signal we're getting from the R2.

[Max]

Yep, can see that now. Sorry for misdirection.

73

Max

Trust me - this is not the VAC, it's the quality of signal we're getting from the R2.