[HCDX]: A-Index

["Gert Nilsson" <gert.nilsson@xxxxxxxxxxxxxxxxxx>]

I think we have to consider the difference of signal path when we discuss
the importance of A-Index. The A-index is a good instrument to decide
adsorption of signals passing the auroral zone. In the northern part of
Scandinavia almost every transatlantic signal passes through this zone and 
very high A-index means almost no signals at all. On the other hand long
periods with  very low solar activity and low A-index seems to favor
signals from Canada. A small disturbance makes signals further south to
come through. A good transatlantic period very often ends with a very good
peak towards the southern parts of the US, Mexico and later exceptional
signals from South America. On the 30th of December 1997 there was a
disturbance reaching earth around 03.00 UTC with a peak for signals from
California and in the morning you could here Colombians on every channel
well after sunrise! Signals from Brazil, Argentina and Uruguay are often
heard when A-index is rather high. When A-index is very high I often have
good reception of Africa and southern Europe here 500 kilometers north of
Stockholm as the powerhouses in Russia and northern Europe are much weaker.

I always check Jan Alvestad Internet page  Solar Activity Report at
http://dxlc.com/solar/

I think it is an excellent source of information. It should be a good
choice also for DX-ers in North America wanting to receive stations in
northern Europe and the Far East.

Gert
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