Friday, 9 February 2018

30m Propagation during geomagnetic disturbance

I've been running WSPR at 200mW with my 30m 1/4 wave vertical from the marsh site for the past couple of days.  It's been very cold and a bit windy, which makes life tough.

Even so, I was lucky to catch a minor geomagnetic disturbance last evening, which started around 19:30UT, and returned to quieter conditions by just after 00UT.  This is the Kiruna plot:

Image: IRF/Kiruna.

The Z component pulses are also interesting in this run.  The other components showed no pulsations.

Z component magnetic pulsations.  Image: IRF/Kiruna.


EA8BFK is a very good receiver, and happens to lie on the exact-same terminator line as my location at this time of year.  This is how he heard my 200mW.  Time along the top, SNR up the side:

It's very interesting to note that my signal was quite weak, but then showed a two-peak phase starting around 21:35UT, when the field was approaching peak southerly deviation.  There is a quieter trough around 22:30UT, just after peak field deviation.  Then, as the field restores to normal, a sharp strengthening of my signal for a few minutes, peaking just after 23:00UT.  That brief signal strength level was not seen again until the advance of dawn-time propagation.

So it seems that 30m, like 20m, provides enhanced propagation during geomagnetic events.

UPDATE.

I've also plotted DP0GVN hearing my 200mW at 10MHz on 08-09 February 2018, the same period as above.


The spots vanish in the approximate period 21:20 - 23:50UT, with a brief 'reconnection' at quite strong levels, but only for a couple of minutes, around 00:00UT.  This superficially coincides with the field recovering to its quiet conditions at that time.  So it looks like the geomagnetic disturbance caused a decrease in propagation in this north-south case.

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