Topband: Recent Conditions

[Nick Hall-Patch]

At 01:29 05/12/2007, you wrote:



>W2PM Responds:
>... BUT
>how is the SFI still in the low 70's when there have been no sunspots?
>I recall the last minima has SFIs in the low 50's, maybe lower.


I'm not sure that 50's are valid numbers for the SFI, at least for 
the values we see reported on a daily basis; I don't recall seeing it 
lower than 65.  I'm sure that others on the list could clarify further.


   The SFI hardly got down into the high 60's during the the last 
solar minimum, 1996-1997; see 
http://www.drao-ofr.hia-iha.nrc-cnrc.gc.ca/icarus/www/daily.html for 
daily values

This past summer, we had a number of runs of mid to high 60's for 
SFI, so it seems that this minimum might have been a little quieter 
than the last one.

As for conditions seeming poorer as one approaches midwinter in spite 
of low solar and geomagnetic indices, medium wave DXers (listeners) 
have noticed this for years, but no-one seems to have come up with an 
explanation.   At one time, it was suggested that stratwarms were 
associated with periods of higher absorption in the winter months, 
but K9LA was not able to find any correlation when he looked at it.

best wishes,

Nick
VE7DXR



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Nick Hall-Patch
Victoria, B.C.
Canada

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