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Topband: condx - more

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Subject: Topband: condx - more
From: (Bill Tippett)
Date: Fri, 28 Dec 2001 21:22:57 +0000
>I observed signals were always there all evening, but went through 
>very strong peaks. Stations that were just at my noise floor (S2) for 
>*very* long periods of time came up maybe ten or twenty dB (to 
>over S-9 on my typical poorly linear "S" meter) as they peaked and 
>then dropped back down to poor levels.
>Here is the solar report for that time period. Note the Aurora level, 
>at the bottom, was way down to 1 for a period of time!!

        My guess is that you are seeing the very dynamic effects of
Auroral absorption.  If you've seen an Aurora or a dynamic photo of
one, they can change VERY rapidly.  Here is a NOAA page with plots of
the Northern Auroral Zone with measurements of power:

>From this data, the Auroral Activity Level in the Northern Auroral
Zone varied from 3 to 5 last night which is roughly equivalent to 
Kp 1+ to 2+

        Here is an animation of the polar plots that you can scroll
through the time period of interest:

        There is some evidence that the Northern and Southern Zones are
reciprocal, and the Southern Zone was varying between Levels of 1 and
5 in some very short time periods (5 at 0208 to 1 at 0328).  These
measurements are just snapshots in time, and I imagine the realtime
energy is varying very rapidly causing the peaking you were seeing.
If you kept notes of signal strengths, you might try to correlate 
them with the power measurements but it makes it difficult when
the satellite passes are only every 20 minutes.  

        Here is another continuous measure of the Earth's magnetic field 
that is very useful when watching for Auroral can see how
dynamically things change (Bz is the one to watch for visual Auroras...
when you see a strongly negative Bz reading, it's time to go outside and 
look up to the heavens!):

There's a wealth of data on Aurora here:
and I don't claim to understand it all...but it is interesting to 
browse through it!

                                                73,  Bill  W4ZV

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