FW: ARLP039 Propagation de K7VVV


From: Ed Tanton (n4xy@att.net)
Date: Fri Sep 21 2001 - 15:31:32 CDT

72/73 Ed Tanton N4XY <n4xy@arrl.net>

Ed Tanton N4XY
189 Pioneer Trail
Marietta, GA 30068-3466

website: http://www.n4xy.com

OK-QRP QRP-L #758 K2 (FT) #00057

-----Original Message-----
From: ARRL Web site [mailto:memberlist@www.arrl.org]
Sent: Friday, September 21, 2001 9:31 AM
To: n4xy@att.net
Cc: Subscribed ARRL Members:
Subject: ARLP039 Propagation de K7VVV

ARLP039 Propagation de K7VVV

Propagation Forecast Bulletin 39 ARLP039
>From Tad Cook, K7VVV
Seattle, WA September 21, 2001
To all radio amateurs

ARLP039 Propagation de K7VVV

Solar flux and sunspot numbers are in a general upward trend since the
beginning of August. If you have WA4TTK's Solar Data Plotting Utility
(available free from http://www.craigcentral.com/sol.htm ), check the
lowerscale showing recent sunspot and solar flux numbers. Another place
to see this trend is at http://www.dxlc.com/solar/ .

The past week had numbers that were down a bit. Average daily solar flux
was down almost 23 points and sunspot averages were off nearly 43
points, when compared to the previous week.

The Autumnal Equinox is this Saturday, and right now is the best time
for HF propagation in many months. 10-meters is getting really good at
this time of year, and will get better (at least in the Northern
Hemisphere) in October and November.

Looking at average sunspot numbers for the past two weeks, this could be
the best Fall equinox of the current cycle for HF propagation. Average
daily sunspot numbers from September 6-19 were 220, but for the same
period last year, it was only 113, and 132 in 1999. We haven't had
sunspot counts this high prior to the Fall equinox since the peak of the
last solar cycle, when the average daily sunspot number was 219 from
September 6-19, 1989.

On September 18 a solar flare near sunspot 9620 hurled a cloud of
particles into space. This is not moving directly toward earth, but
could sweep past us early Friday. The predicted planetary A index for
Friday through Monday is 15, 12, 10 and 10. Predicted solar flux for
Friday through the middle of next week is around 230.

Holographic images of the sun's far side show a large
southern-hemisphere sunspot. Although this is too far off to predict
with great accuracy, based upon the previous solar rotation solar flux
may peak near 240 around October 7 or 8.

Sunspot numbers for September 13 through 19 were 223, 216, 183, 169,
159, 215 and 224 with a mean of 198.4. 10.7 cm flux was 239.7, 236.6,
219.3, 207.1, 199.1, 203.8 and 198.8, with a mean of 214.9, and
estimated planetary A indices were 18, 10, 15, 8, 10, 8 and 8 with a
mean of 11. NNNN /EX

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