IQ recording playback produces invalid / meaningless output

[NagyDominikGabor]

I'm currently using the Ground Station application from this repository with an RTL-SDR device. The waterfall diagram works as expected, and I can see signals clearly. I am also able to record IQ data without any apparent errors.

However, when I try to play back the recorded IQ data, the output appears to be incorrect or meaningless (it does not resemble the original signal in any usable way).

To help illustrate the issue, I have attached a PDF that includes:

• My SDR configuration/settings
• Screenshots of the waterfall during recording
• The resulting output after playback
• GroundStation_IQ.pdf

Could you please advise:

• If I might be missing a required configuration step for proper IQ recording/playback?
• Whether there are known issues with IQ playback in the current version?
• If there is a recommended format or workflow for recording and replaying IQ data?

Any guidance would be greatly appreciated.

Thanks in advance for your help!

[sgoudelis]

Can you please instead of attaching PDFs sent over the screenshots as images attached here ? Its a bit safer this way

[NagyDominikGabor]

Here is the SDR:

Here is the waterfall view:

I recorded an FM signal and then tried to play it back immediately afterwards, but all I got was an uninterpretable spectrum.

I also tried playing it with GNU Radio (SigMF Source), but I didn't get any meaningful signals either.

[sgoudelis]

What settings did you use when this happened ? Sample rate, gain, etc