Propagation Forecast Bulletin #36 de K7RA:
W1AW Bulletin via the ARRL
September 7, 2012
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Propagation Forecast Bulletin #36 de K7RA:
QST de W1AW
Propagation Forecast Bulletin 36 ARLP036
>From Tad Cook, K7RA
Seattle, WA September 7, 2012
To all radio amateurs
SB PROP ARL ARLP036
ARLP036 Propagation de K7RA
A surprising jump in solar activity occurred this week. Average
daily sunspot numbers rose nearly 55 points (about 74%) to 128.7.
Average daily solar flux values were up over 28 points to 136.9. A
pair of coronal mass ejections on September 3 and 4 excited Earth's
geomagnetic field, causing A index values to jump. Middle latitude A
index on September 2-5 was 14, 23, 14 and 24. The planetary A index
on those dates was 12, 32, 13 and 28, while high-latitude college A
index (Fairbanks, Alaska) was 48, 52, 39 and 49.
Solar flux predictions show flux values peaking today (September 7)
at 130, then on September 8-12 solar flux of 125, 120, 115, 110 and
105. Solar flux on September 13-16 is predicted at 100, then 95 on
September 17-22, then 100, 110, 115, 120 and 125 on September 23-27,
and peaking at 130 on September 28. From September 29 through
October 2 solar flux is predicted to be 120, then 115 on October
3-5, and 110 on October 6-7.
The planetary A index is predicted at 8 on September 7, the 7 on
September 8-10, 5 on September 11-13, 10 on September 14-16, 5 on
September 17-19, 10 on September 20, 8 on September 21-23, and 5 on
F.K. Janda, OK1HH predicts our Earth's geomagnetic field will be
quiet on September 7, mostly quiet September 8, quiet to unsettled
September 9, quiet to active September 10, mostly quiet September
11, quiet to unsettled September 12, quiet to active September 13,
mostly quiet September 14, quiet to active September 15, quiet to
unsettled September 16, quiet September 17, quiet to unsettled
September 18, mostly quiet September 19-20, quiet to unsettled
September 21, quiet to active September 22, quiet September 23-28,
and active to disturbed September 29.
Our 3 month moving average has an update, now that August is done,
and the average daily sunspot number for the trailing three months,
June 1 through August 31 was 91.9. The three month moving averages
centered on July 2011 through July 2012 were 63, 79.6, 98.6, 118.8,
118.6, 110, 83.3, 73.7, 71.2, 87.3, 91.5, 96.5 and 91.9. The monthly
averages of daily sunspot numbers, May through August 2012 were
99.4, 90.1, 99.6 and 85.8.
NASA has a revised forecast for the peak of Cycle 24, and it looks
very interesting. Instead of a peak in Spring 2013 with a smoothed
international sunspot number of 60, the peak is now predicted for
Fall 2013, with the smoothed sunspot number prediction revised to
76, about 27% higher. Perhaps Cycle 24 will have a double peak, the
first being in Fall 2011 and the second in Fall 2013.
The revised forecast is at
For VHF propagation, Ken Tata, K1KT tells us to check
http://aprs.mountainlake.k12.mn.us/ which he says is "great for
live, real time propagation as they are derived from global APRS
reports. Unfortunately, most of the rest of the world has no APRS
stations. If there are Es paths the red plumes can be huge!"
For tropo predictions, check the Hepburn maps at
http://www.dxinfocentre.com/tropo.html. These maps are updated daily
at 1PM EST, I believe. By using weather maps and this site you can
sometimes do your own tropo forecasts."
Ken says, for the last hour or so of reported contacts, check
I checked conditions in Europe on 10 meters at 1200 UTC on September
7, and saw lots of tropo and sporadic-E propagation indicated.
Back on August 31, Jeff, N8II reported: "The bands have gone from
pretty punk to exciting in just a couple of days, no wonder with SFI
currently 135 and K1, lots of over the pole DX worked yesterday
including RI1FJ (Franz Josef land) for a new band country at 0045Z
on 12M CW, 1 hour after my sunset and about 03 hrs in FJL! More
details to follow. 15 was open 1/2 hr after sunrise to EX8MLE and
UK8 this AM."
Roland Anders, K3RA of Elkridge, Maryland reports, also from August
31: "That jump in the SSN really seemed to liven things up to Asia
on the bands here in MD-especially on 10 and 12. Wednesday night was
a precursor of things to come. 15 was open to JT, HL, YB, and
several JAs as late as 0225Z.
"Thursday morning I worked a few Asians on 20 at 1200Z or so, and at
1220Z I happened to see a huge number of spots on 10 meters by
Europeans. The 10 meter band map is usually pretty blank at that
hour. 12 was open, too, but that was not nearly so unusual as the 10
meter spots. So I tuned up to 10 and immediately started working
EUs, and ran 15 of them in about 30 minutes. Then I moved to 15 CW
at 1320Z and worked a couple of Chinese stations that were new
stations for me. After some more EUs, I moved to 15 SSB and worked
HS, two YBs and finished with 9N1AA at 1452Z.
"Friday morning, I got on 15 at 1200Z and worked some JAs, EX, a
couple of HS stations, China, VU, a couple of YBs and A7. I moved to
10 at 1310Z to work 5H3ME on CW, then to 12 for a good run of EUs.
Back to 10 at 1500Z to pick up YB4IR, then to 15 to work YB, JY, and
VU. At 1525Z I moved to 12 SSB and snagged XU7AAJ. That's several
hours after his sunset, a new band country for me. 12m was also good
for OD5ARMY on SSB and an Israeli mobile.
"Friday night at midnight on 15 I heard a strong JA working RX9 and
could hear both sides of QSO. So I called CQ and worked some JAs.
"Here on the east coast, I often find that when I tune 20 at 1200Z
and later, I find very little if any activity, but CQing over the
pole often produces JA and other Asians. So, if all you do is listen
and look for spots, you may be missing some good opportunities. Same
can be said for 17 meters, which is usually open to EU at that hour,
but Asians can be enticed to answer CQs. And look for those openings
over the pole on 10 and 12 mid-morning East Coast time--it's that
time of year."
Bob Foster, N9BGC of Waverly, Iowa wrote on September 2, "This past
week saw several solid DX openings from NE Iowa to Eastern Europe,
the Pacific and South America on 15 meters SSB. The band stayed open
well past sunset. My station is very basic - 100 watts into a ground
mounted Gap vertical. Legitimate 5-7 to 5-9 signals were sent to
Poland, Croatia, Hawaii, Brazil and Spain. Not exotic DX, but quite
consistent 4,000 to 5,000 miles. It was quite satisfying considering
my modest station. Normally, I have to rely on 20 M and 40 M CW for
Fred Laun, K3ZO sent comments about this year's All Asia Phone
contest. "Given that this contest is possibly the most affected by
solar effects since the beam headings from here to the area where
the maximum number of possible QSOs is located go right through the
north magnetic polar area, I thought it would be interesting to
compare my score this year to the score in last year's contest."
In 2011 with solar flux at 119, he had 96 contacts on 40, 93 on 20,
and 196 on 15, with a total of 385 QSOs and 70,455 points. In 2012
with solar flux at 145 he had 19 QSOs on 40, 81 on 20, 298 on 15 and
4 on 10 meters, total 402 QSOs, and a score of 81,606.
"The 15 meter numbers this year would have been even more lopsided
if I hadn't had to break off great runs twice on Friday night due to
equipment problems, and if I hadn't had to shut down almost
completely during the best hours to Japan Saturday night because of
thunderstorms. My 140 foot tower took a direct lightning hit at 9:45
"The main difference between the two years was the existence of a
great opening to Japan on 15 Saturday morning between 1200 and 1400
UTC. This opening did not exist during last year's contest, when the
furthest east that 15 opened in the same time frame was to Thailand.
Unfortunately, the great Saturday opening this year did not repeat
itself Sunday morning because of a solar proton event which had the
effect of lowering the MUF over the pole in that direction. However
propagation to that area on 20 on Sunday morning was much better
than it had been on Saturday morning which gave me a chance to
fatten up my 20 meter numbers. RU0AI registered a mind-boggling 45
dB over 9 on my S-meter during the Sunday morning run.
"The other difference of note was that I was able to make Asian QSOs
on 10 this year; not many -- one UA9, two HZs and an A6, but last
year I didn't have any. As always, I had no packet in the shack on
purpose so I missed some 10 meter stuff I'm sure. K3TW in Florida
reported hearing HS0ZJU on 10. Ken, KE3X piloted the N3HBX station
to much better numbers than mine. Congrats to Ken for a job well
For a peek at the K3ZO antenna farm, go to
and zoom in, then click on Aerial and Bird's Eye. You can drag the
image around, and also select views from four different images in
four directions on the compass rose in the upper right. Quite
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,
http://arrl.org/propagation-of-rf-signals. For an explanation of the
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past
propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. Find more good
information and tutorials on propagation at
Monthly propagation charts between four USA regions and twelve
overseas locations are at
Sunspot numbers for August 30 through September 5 were 118, 144,
120, 108, 156, 150, and 105, with a mean of 128.7. 10.7 cm flux was
127.8, 130.5, 145.6, 142.3, 141.6, 137.6, and 132.7, with a mean of
136.9. Estimated planetary A indices were 4, 3, 7, 12, 32, 13, and
28, with a mean of 14.1. Estimated mid-latitude A indices were 4, 3,
8, 14, 23, 14, and 24, with a mean of 12.9.
Source: W1AW Bulletin via the ARRL.
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