Hello Stefan,
Very interesting received-signal spectrum images! Last night I was wondering what the receive characteristics of your ground-loop antenna would be, so your scope spectrum images are a nice surprise.
I looked particularly at the image of 100 kHz span, to see if there was evidence of azimuth directionality, or preference for local (high elevation angle) signals (for received signals).
I could not see evidence of azimuth directionality or high-elevation-angle preference, but I am not too familiar with the bearing and ERP relationships of FTA, GQD, DHO38, (JXN?) and other signals that I tried to identify.
I thought I could see NAA (next to DHO38, at a relevant SNR for the 101.73Hz? bandwidth) and NAU in your spectrum image, but not NML (which was pre-dawn, not surprising to not see it). I interpreted this as evidence of good low-angle sensitivity; but perhaps I didn’t identify the transmitters correctly.
Did you happen to notice any indication of azimuth directionality, or preference for local (high elevation angle) signals, in your received-signal spectra?
Thanks for posting the great images.
73,
Jim AA5BW
LF/VLF/ULF,
Another thing to report. With the scope i took some spectra showing the signal amplitudes of strong LF and VLF stations. The 900m long antenna (grounded ends) was simply connected to the probe of the scope. Maybe not the best resolution but it gives an idea of the signal voltages measured at the feed point. A connected sound card would have to deal with these voltages. The strongest signal is at about 180 kHz, obviously Europe1,a carrier and AM sidebands are visible.
I'll try to receive ZEVS and the Schumanns from that antena soon.
Spectra captures attached.
73, Stefan
