I use the SuperSID receiver (basically a VLF preamp) & software that comes with to send telemetry to the Stanford SOLAR Center. I also joined the AAVSO solar group to get a Alpha number (I'm A155) and send them my manually processed SID events start, peak and times once a month using their free SID Data Grabber software (SDG). The antennas is the no-longer available Cross Country Wireless active short vertical VLF to HF antenna. I use a 30 m run of RG6 between the antenna and its bias-t.
www.radio-astronomy.org/store/projects/supersid
I did purchase the VLF loop antenna kit but haven't gotten around to winding the loop to compare it with the CCW active short vertical.
The receiver plugs into my 96 kHz sampling soundcard and that feeds the SuperSID software and my Spectrum Lab live display of the 4 VLF transmitters I monitor. I also calibrated it to use dBm units to make it much easier to compare SID events between another VLF transmitter's signal.
The one big problem with the SuperSID software is that it's calibrated to use power spectral density (PSD) in dB/Hz, the Standford SOLAR Center graphs have no units and the SDG software displays in logarithmic values of something but all charts are separate and you can't compare anything because different scales are used. So I modified the stock VLF monitor configuration that comes with Spectrum Lab and calibrated everything in dBm and display all signals on the same chart so comparisons are much easier to make. Subtracting dBm values gives results in dB values (but addition isn't allowed) and dBm also converts easily to standard S-units.
Note the SDG and Spectrum Lab displays of the same M9.6 solar flare induced SID events with NAA and NML. The SDG display, because of the two different scales used, seems to imply that NAA's VLF signal was more affected than NML's. But the Spectrum Lab display says otherwise and you can easily calculate the dB difference between both.
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