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ARRL Propagation Bulletin ARLP046 (2012)

ARLP046 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 46  ARLP046
From Tad Cook, K7RA
Seattle, WA  November 16, 2012
To all radio amateurs 

ARLP046 Propagation de K7RA

Suddenly this week we see an exciting and dramatic rise in sunspot
activity. The daily sunspot number was 188 on Monday, November 12,
higher than it has been in over a year. The last time the daily
sunspot number was as high was on November 9, 2011, when it was 208.
Prior to last November, we have to go back nine years into the
previous solar cycle, November 26, 2003, to find a number this
large.  Back then the daily sunspot number was 209.

The average daily sunspot number from November 8-14 was 104.9, over
twice the previous week's average of 49.7. Average daily solar flux
was 129.5, more than 32 points above the previous week's average.

A coronal mass ejection on November 13 caused a geomagnetic storm on
November 13-14, which drove the planetary A index to 33 on November
14. Aurora was visible across the Northern United States. NASA
estimates a 40% chance of M-class solar flares today, and if any
come from sunspot group 1614, they would be Earth-directed.

The NOAA/USAF prediction on November 15 shows solar flux at 145 on
November 16-19, 140 on November 20-21, 135, 125 and 105 on November
22-24, 100 on November 25-26, 95 on November 27, and 90 on November
28 through December 1. Then they predict 95, 100 and 105 on December
2-4, 110 on December 5-7, and 115 on December 8-11

Predicted planetary A index is 8 on November 16-17, 5 on November 18
through December 4, 10 on December 5-8, 5 on December 9, 8 on
December 10, and 5 on December 11-15.

OK1HH from the Czech Republic expects quiet conditions November
16-18, quiet to unsettled November 19, quiet November 20, mostly
quiet November 21, quiet to unsettled November 22, mostly quiet
November 23-24, quiet November 25-26, quiet to unsettled November
27, active to disturbed November 28, mostly quiet November 29
through December 2, quiet to unsettled December 3, quiet to active
December 4, and quiet December 5-8.

Conditions should be good for this weekend's ARRL SSB Sweepstakes.
This is a domestic contest which counts ARRL Sections as
multipliers, and you can find details at Even if you aren't competing, it is
fun to get on and just casually operate. If you do this toward the
end of the contest, you will make some operators happy who are
trying to squeeze out a few more points. Toward the end they have
been at it for more than a day (the contest lasts 30 hours), while
searching for new contacts they've heard the same calls over and
over, and you joining in during the last few hours will generate
fresh excitement.

Max White, M0VNG of Worcester, UK calls our attention to an amateur
astronomer in Bangladesh who runs a web page for monitoring Sudden
Ionospheric Disturbances at Fortunately, I have not
witnessed any SID events on this page.

for a frequently updated blog about space weather.

Stu Phillips, K6TU has a fascinating and powerful new online tool
that uses VOACAP, but automates the whole process and generates
useful graphics. You can read a description of it at  VOACAP uses the predicted
smoothed sunspot number for the month, and will generate the same
prediction for the whole month. So there is no variation from day to
day. With Stu's service you set up your location, select the month
and year, decide if you want all HF bands or just the five bands
contests use, select either a worldwide map or just North America,
select typical antenna and transmit power configurations, and
shortly you will receive an email with a link to PDF images for each
hour for each band. It's fun to step through the hours and watch the
propagation change.

If you would like to make a comment or have a tip for our readers,
email the author at,

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at For an explanation of the
numbers used in this bulletin, see An archive of past
propagation bulletins is at Find more good
information and tutorials on propagation at

Monthly propagation charts between four USA regions and twelve
overseas locations are at

Instructions for starting or ending email distribution of ARRL
bulletins are at

Sunspot numbers for November 8 through 14 were 71, 65, 68, 106, 188,
108, and 128, with a mean of 104.9. 10.7 cm flux was 104.1, 115.1,
122.2, 133.3, 143.8, 146.2, and 142.1, with a mean of 129.5.
Estimated planetary A indices were 3, 2, 2, 3, 5, 15, and 33, with a
mean of 9. Estimated mid-latitude A indices were 2, 1, 1, 2, 4, 10
and 21, with a mean of 5.9.


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