SID
(Sudden Ionospheric Disturbance)
This system allows you to detect solar flares,
during daytime hours, without a Ha-telescope and the associated clear weather
precondition. The working principle is to monitor the behavior of the ionosphere. The
D-layer existence is a direct function of solar X-rays (~ 0,1 nanometer). If there is an
excess flux, e.g. from a solar flare, the ionisation increases accordingly. With a
suitable radiosignal from some distant (no groundwave present) transmitter, one can
identify solar flare events by measuring and following the signal level reflected by the
D-layer. When it comes to choosing a transmitter, the field is wide open for experiments.
A "long wire" aerial picks up the signal outdoors. My "black box"
contains several OP-Amps tuned for the frequency proper and a rectifier. The signal is
plotted with a pen-recorder. I detect
60 kHz from Rugby, UK. Nowadays one uses a A/D-converter hooked up
to a computer.