PPM or Hz - to be or not to be?!?

[Frank Thomsen]

Newbie to SparkSDR, 20+ years of SDR experience, started with the kitchen table kit FlexRadio "SDR 1000" - great fun!

I use SparkSDR on a RadioBerry (5 band FT8 skimming) and an SDRplay (6M monitoring) - on the RadioBerry frequency calibration is done in Hz and is shifts about 120Hz per 5 MHz. With the SDRplay, calibration is done in PPM and there is no shift.

Christophs piHPSDR recently changed from Hz to PPM and the 120Hz/5MHz is no longer an issue, frequency tracks perfectly.

On a side note I did try out the NTP based correction feature on the RadioBerry. I do not run a true NTP client, mind you, but I did get some numbers and they were way off, so I'll probably have to re-visit that feature.

My question is: How come SDRplay does PPM correction and RadioBerry/Hermes 2 Lite does Hz???

Vy 73

Frank - OZ5aci