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ARRL Propagation Bulletin ARLP040 (2010)

ARLP040 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 40  ARLP040
From Tad Cook, K7RA
Seattle, WA  October 8, 2010
To all radio amateurs 

ARLP040 Propagation de K7RA

Solar activity quieted down over the past week.  There were no
sunspots on Wednesday and Thursday, October 6-7, and the average
daily sunspot number declined nearly 18 points to 27.6, compared to
the previous week.  Average daily solar flux values were off over
three points to 81.  Predicted solar flux for the next ten days,
October 8-17 is 76, 78, 78, 80, 80, 80, 80, 82, 81 and 83.

The same forecast predicts a planetary A index of 5 on October 8-10,
10 on October 11, 7 on October 12-14, and 5 on October 15-17.

Looking at the STEREO image ( early
Friday morning shows an active region in our Sun's southern
hemisphere passing over the eastern horizon.  This has not yet
manifested any sunspot groups.  Currently the STEREO image covers
about 94.8% of the Sun's surface.  That coverage should reach 96% at
the end of October, 97.4% at the end of November, 98.7% at the end
of this year and 99.8% at the end of January 2011.  Finally on
February 7, 2011 STEREO should reach 100% coverage.

Jeff Hartley, N8II of Shepherdstown, West Virginia sent in a report
nearly a week ago concerning Wednesday, September 29:

"Wednesday was a very good day for propagation, lots of Asiatic
Russians with good signals were worked around 0100z (Thursday Z
time) on 20 meters. Also JAs were heard after 2300z on 20 for the
first time in quite a while; JT1BV was near S9 on SSB. Thursday, my
day off, was not as good with 15 opening around 1300z (late) to EU
with some good signals mostly from southern EU. I heard no signals
all morning on 12 meters except for beacons including ZS6DN; CQs
toward ZS yielded nothing. In the evening XW1B was heard very weak
on 17 meters CW (had worked him a few days prior with better signal)
and on 20 CW at 0030 he was about S7 and commanding a CW pile-up. I
had quite a struggle catching 9M6XRO/p or 9M6DXX/p on IOTA OC-235
due to a disturbance at first, then my 20 meters amp failed and
couldn't crack the EU jungle calling on Sunday. I also had no luck
Monday around sunrise on 40 (high QRN in 9M6?), then finally
succeeded on 17 CW around 2200z Monday and that QSO was easy."

Larry Godek, W0OGH of Gilbert, Arizona send in this report on
October 1:

"What a week it's been on 15.  Europeans galore, VP8, DU, 5R8, YY0,
5X1, 8R1, 4Z5, EA7, YU, A71, OE, YO and HZ.  Early AM for the
Europeans and Middle East, around noon for Africa and the South
Atlantic/South Americas.  On the 19th I worked 7V2, 9H1 and ER4 on
SSB.  Makes you want to jump up and shout!  Now for that TS7 that
everyone is working and I can't even hear him.

"Some of the SSB contacts have been rough because I only have 100W
but playing the propagation game has paid off.  Getting thru the
Atlantic and Midwest wall is a chore indeed.  Trouble is that you
can't hear much of the folks to the east when they are working east
and south and you're working the same directions.

"I put up a 5 element 15 meter beam at 25 feet this spring expecting
great results.  Well I think it's helping a bit. A kW or bit more
power would do wonders but I'm sticking to my guns and doing it with
100W and better antennas."

Gordon Curling, VE3KKL of Kars, Ontario asked why the solar flux
numbers presented at the end of this bulletin are not the same
numbers he hears on WWV.

The solar flux values are actually from the same source at Penticton
in British Columbia.  The difference here is we present them
resolved to one-tenth of a point, but WWV rounds them off to whole
numbers.  So for example, on March 13 Gordon recorded 92 from WWV,
and the observatory reported 91.8.  On February 8 Gordon recorded 94
from WWV, and the observatory reported 93.7.

The same numbers reported on WWV are on the web at, and you can go to to see the original numbers.  Just look at
the noon daily reading (there are readings in the morning and
afternoon, but the noon reading is the official daily number) and
look at the observed solar flux in the fluxobsflux column.

Bob Karpinski, WB8B of Clinton Township, Michigan reports, "With the
recent spike in solar flux into the high 80s, 12 meters produced a
quick but nice little opening for me into EU around 1630z on October
2 with a 5w/QRP CW QSO with S57DX. By being in the right spot at the
right time of the day, QRP DX is still achievable and should only
get better on the higher HF bands this Winter with the flux finally
perking upwards."

On Oct 5th at 1530z Joe, CT1HZE from Southern Portugal reports a 2
meter sporadic-E opening to France.  Although the opening was just 8
minutes long and only one QSO was made with a French station over a
distance of about 1800 km, Joe notes this event is quite remarkable
as it is the first time that 2 meter Es were reported in the month
of October in Europe.

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

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

Find more good information and tutorials on propagation at

Sunspot numbers for September 30 through October 6 were 45, 44, 42,
28, 23, 11, and 0, with a mean of 27.6. 10.7 cm flux was 89.9, 86.7,
85, 80, 76.1, 75.4 and 74.2 with a mean of 81. Estimated planetary A
indices were 1, 3, 2, 3, 3, 6 and 8 with a mean of 3.7. Estimated
mid-latitude A indices were 1, 0, 0, 1, 2, 6 and 5 with a mean of


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