WSPR reception at 132km

G0LUJ has excellent low noise levels, and very sensitive receiving capabilities.

Last night, a moderate geomagnetic disturbance took place for a while.  I wondered again whether this would show up in what I used to think was exclusively ground wave propagation.  But this latest plot shows this not to be the case, as the reception ceases as the evening progresses.

Here is the plot of reception at G0LUJ of my daughter's 200mW into a 1/4 wave elevated vertical in an open field, marshy location.

See the blip?

The reception reports at G0LUJ do not vary very much at all over the day under normal conditions.  But there is a clear outlier at around 01:40UT (24/02/2018), where my daughter's signal suddenly appears from nowhere at a strong -17dB S/N.  It then drops back to near-daytime conditions in the mid to lower -20s dB.

The sharp appearance from the noise is correlated, as seems to be most usually the case, with the recovery phase of the geomagnetic field from a disturbance.  I assume it is a result of reconnection of field lines (which is why the magnetogram below shows a field disturbance at an earlier time, but the enhanced propagation and aurora do not occur until a bit later).

Here's the statistical aurora at 23:40UT, just after the activity had picked up:

NOAA/SWPC

By 01:40UT, things were looking decidedly more lively:

NOAA/SWPC

And the Kiruna magnetogram shows the high-resolution detail:

IRF/Kiruna.