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ARRL Propagation Bulletin ARLP047 (2006)

ARLP047 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 47  ARLP047
From Tad Cook, K7RA
Seattle, WA  November 17, 2006
To all radio amateurs 

ARLP047 Propagation de K7RA

This week saw the odd combination of the average daily sunspot
number declining while the solar flux rose. It isn't so odd for this
to happen when there are very few sunspots, and one rises slightly
while the other declines slightly. But this time, the solar flux
rose quite a bit. The average daily sunspot number dropped nearly 19
points to 27.7, and average daily solar flux rose over 8 points to

There is a big sunspot, number 923, currently moving off center to
the western limb. This sunspot is so large that it could be seen
unaided at sunset, although this is not safe viewing. Perhaps this
spot radiated plenty of energy at 2.8 GHz (the frequency at which
solar flux is measured), but the combined area and number of spots
didn't make a high sunspot number.

Solar flux is measured daily near Penticton, British Columbia since
1991. Prior to 1991, measurements were made at Ottawa. You can see a
photo of the 2.8 GHz antenna here,, and
you can read about it at, and

This week is the phone weekend of ARRL Sweepstakes. Sweepstakes is a
very popular activity in which the emphasis is on working domestic
stations in as many ARRL Sections as possible in the United States
and Canada, rather than DX. You can only work any station one time,
even if you change bands, and the multiplier is the number of ARRL
Sections that you work. You can see the rules at,

Conditions should be good this weekend, although today (November 17)
unsettled geomagnetic activity is expected. After today geomagnetic
conditions should stabilize. Predicted planetary A indices for
November 17-20 are 15, 10, 5 and 5. Geophysical Institute Prague
predicts unsettled to active conditions for November 17, unsettled
November 18, quiet to unsettled November 19, quiet November 20-22,
and quiet to unsettled on November 23.

The predicted solar flux is 95 through the weekend. This is
relatively high for this point in the sunspot cycle. If we had zero
sunspots we would expect to see the solar flux nearly 30 points
lower, around 67.

10 and 12 meters continue to produce openings over long distances,
even though the Fall sporadic-E season probably peaked in October.
Ray Parker, ND6S of Sutter Creek, California reports that on
November 10 he worked VR2BG and VK5BC just after 0200z on 10 meters,
and heard a JA and ZL station. On the same day, but 7 hours earlier
Roger Edwards, K1GBS in Tampa, Florida worked Arizona and Wyoming.

Mike Schatzburg, W2AJI of Tryon, North Carolina reports fantastic 20
meter conditions every evening into South Africa and the South
Pacific. Mike wrote, "20 Meters has had fantastic short path
propagation both into the South Pacific, and into South Africa each
evening. On 11/11 and 11/12, between 0500 and 0630 UTC, the band has
been fully open, with low noise conditions, and very little
stateside QRM on SSB."

He continues, "Most 100 watt dipole stations produce S7 signal
reports, with the high power DXers and Yagis producing S9 plus 10 DB
signals on my calibrated Mark V S-meter. There is very little
fading, and the contacts are solid. Outstanding contacts were had
with ZS2EC, ZS1AU, ZS4U, and ZS1YL amongst many more strong stations
on Nov. 11. On Nov. 12, the same bi-directional conditions existed,
about the same 8,000 mile plus skip distances with VK3SS, VK2GWK,
VK2MAD, and ZL2AIA. These stations report very little activity being
heard from the US, and the pileups which ensued after calling just
one CQ were very large indeed."

He goes on to say, "As usual I was using a five element monoband
Yagi, with a 44 foot boom at 75 feet (see The base of
the tower is at 1002 feet on a very steep hill in the Blue Ridge."

Mike ends with, "I believe that conditions will be improving, but
more ideal propagation could not be found this late at night when
you have quiet as well."

Mike sure has a wonderful 20 meter antenna.

Hector Garcia, XE2K wrote in a week ago after returning from the XF4
operation on the Revillagigedo Island Group in the Pacific. He said
he worked many JA stations on 10 meters, and there seemed to be
several good openings on 10 and 12 meters with strong signals, but
not many stations actually on the air.

I received an email noting that Thomas Ashcraft, mentioned in last
week's propagation forecast bulletin isn't really an astronomer.
This is the fellow who recorded Sun noise on HF with 2 receivers on
18.7 and 22.2 MHz, then made stereo recordings out of them. Ashcraft
is actually an artist, and if you do a web search for his name,
you'll see reviews of his interesting and unusual work in the New
York Times and Art In America. Last week I said he used antennas
aimed at the Sun, but in fact these are just two dipoles cut to
frequency. You can see his web site at,

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 at, For a detailed
explanation of the numbers used in this bulletin, see, An archive of past
propagation bulletins is at, .

Sunspot numbers for November 9 through 15 were 29, 13, 13, 18, 30,
41 and 50 with a mean of 27.7. 10.7 cm flux was 89.4, 91.1, 97,
96.7, 95.2, 94.5, and 96.1, with a mean of 94.3. Estimated planetary
A indices were 10, 36, 20, 7, 2, 4 and 5 with a mean of 12.
Estimated mid-latitude A indices were 7, 29, 20, 9, 1, 3 and 6, with
a mean of 10.7.


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