>> The 5 uHz offset may come from the fixed samplerate in the sr file. The real samplerate is drifting of course, so there may be very small offsets to the value in the file.

Maybe not. With samplerate lock activated in SpecLab, a samplerate error should not affect the center frequency, and only scale the frequency offset entered into the EbNaut decoder. In my settings, the FFT is usually centered on 8270.0 Hz, so with 0.5 ppm SR uncertainty Stefan's signal at +0.1 Hz might be misplaced by a negligible +-0.05 uHz. However as far as I know, Alex has anyway centered his FFT on 8270.1, so the samplerate deviation has no influence on frequency and phase. Thus the observed 5 uHz offset is more likely due to a gradual change of propagation phase.

Best 73,
Markus

-----Ursprüngliche Mitteilung-----
Von: DK7FC <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Mo, 6. Mrz 2017 22:01
Betreff: Re: VLF: Tonite...