vlfrx-tools ⁽²⁾

SAQ was received fine here on the 24th December for their Christmas broadcast at 08:00. This was again using the Airspy HF+ Discover and YouLoop in the loft. I had a bit of time to fiddle with settings in SDR# this time, reducign the bandwidth to 100Hz and trying the HF AGC on and off - leaving it on produces better audio but really not much difference between on and off. The signal from SAQ was showing as -100dBFS vs -110dBFS background. Nothing at all received using vlfrx-tools via the UMC204HD + PA0RDT mini whip. That does show the same large peaks above 19kHz but not the one at about 16.5kHz (see above) nor that smaller peak seen at about 21kHz, so no surprise it did not see SAQ. But never mind, it's still useful. The Youtube recording of the event can be seen at https://www.youtube.com/watch?v=0CQZmW_vE00

Here is a quick and dirty comparison between the Behringer UMC204HD + PA0RDT mini whip and the Airspy HF+ Discovery and YouLoop looking at a similar amount of spectrum from 0 up to 96kHz or so. First the UMC204HD: And the Airspy: This was not done in any scientific fashion, it's just to show that the soundcard method works ok but is not as good as the Airspy. No surprises there and this is no criticism of either method. I can see the utility of the soundcard method when coupled with the vlfrx-tools package as all manner of analyses become possible. I have only just started reading about that.