SB PROP ARL ARLP035
ARLP035 Propagation de K7RA
Average daily sunspot numbers this week moved from 101.7 to 113.4,
while average daily solar flux changed from 111.8 to 130.5. The
active day according to geomagnetic indicators was Wednesday, August
27, when the planetary A index reached 20. This was the result of a
CME which created aurora at both north and south poles.
Predicted solar flux is 115 on August 29 to 31, 120 on September 1 and 2,
then 110, 105, 110 and 120 on September 3 to 6, 125 on September 7 and 8,
then 120, 125, and 130, on September 9 to 11, then 135, 130, 135, and
140 on September 12 to 15, then 145 on September 16 and 17, 140 on
September 18 and 19, 135 on September 20 to 23, and 125 on September
24 and 25.
Predicted planetary A index is 10, 8, 12 and 18 on August 29 through
September 1, 5 on September 2 to 5, 8 on September 6 and 7, 12 on
September 8, 5 on September 9 to 12, 8 on September 13, and 5 on
September 14 to 23.
OK1HH predicts quiet to active geomagnetic conditions August 29,
active to disturbed August 30, quiet to active August 31 through
September 1, quiet September 2, quiet to unsettled September 3 and 4,
quiet September 5, mostly quiet September 6, quiet to unsettled
September 7 and 8, quiet September 9 to 12, quiet to unsettled September
13, active to disturbed September 14 and 15, mostly quiet September
16 and 17, quiet September 18 to 21, quiet to active September 22 and
active to disturbed September 23.
Costas Krallis, SV1XV of Athens, Greece wrote about the numbers at
the end of last week's bulletin: "Now something is wrong about the
mean values. How can the average of seven numbers, all of them lower
than 120, be 138.8? And how can the average of seven numbers, none
of them lower than 4, be 3.7?"
Costas is correct, but how could I be so wrong? To correct the
record for last week's bulletin, the average daily sunspot number
for August 14 to 20 was 101.7, average solar flux was 111.8, average
planetary A index was 6.7 and average mid-latitude A index was 7.1.
NOAA has a couple of new web pages they are rolling out. Check out
the Space Weather Enthusiasts page at
and the Data Access page at
http://origin-www.swpc.noaa.gov/content/data-access . They also seek
your comments at
Chip Sufitchi, N2YO/YO3FWC sent a note about a Romanian propagation
bulletin, which just published its five-hundredth edition.
Chip wrote, "I wanted to inform you that the Weekly Propagation
Bulletin hosted by the popular Romanian web site Radioamator.ro just
released issue 500. One month ago the web site celebrated 10 years
of continuous presence on the web by activating a special call sign
(YR10RRO) and releasing a decennial award.
The main section in the bulletin discusses some interesting
propagation events occurring recently, including VHF/UHF if any,
propagation facts during a recent major contest as reported by
participants, or a forecast for the weekend's contest, if any
significant one is scheduled. It does also inform readers about
interesting articles with propagation/solar content found on the
internet, or recent reported facts about the current solar cycle.
The last section is a one week forecast for solar and geomagnetic
activity, based on NOAA and IPS reports. Part of the bulletin is
also the monthly propagation diagrams, generated on the first of
each month, showing propagation in several directions centered on
YO. The simulation is powered by VOAprop, a software tool created by
The web site is here:
You can use Google Translate to read it in English. After clicking
on the link to any of the bulletins, just copy the URL and paste it
here in the box:
Of course you can select any language of your choice, and it at
least gives you an idea of what the text is about.
Pete Corp, K2ARM sent a lament about the end of the sporadic-E
"I guess 6 meter E skip has disappeared for this season. July 21 and
July 23 were the only European openings that I had. I used an
overgrown dipole and 40 watts. I worked: G8BCG, G4FJK, ON4IQ, F6BLP,
EI3KD, F8GGD, GM3SEK, G0JHC, F6AUS, F2DX, IK5MEJ, and Bert, F6HKA.
It was nice while it lasted. Thanks for your reports. I sure hope HF
conditions will get better soon."
The overgrown dipole Pete uses is an Extended Double Zepp antenna.
Do a web search for "EDZ antenna" or "double extended zepp" or
"extended double zepp" for more information on this old, interesting
and effective antenna. You will discover many useful references. I
first ran across this antenna in the 1970s when operating 2-meter FM
simplex while parked near the top of Mount Sutro in San Francisco. I
worked Art Childs, W6TYP (SK) who was using one oriented vertically
on 2 meters, I think somewhere near Salinas, and later he sent me a
diagram showing how it was built.
For more information concerning radio propagation, see the ARRL
Technical Information Service 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
information and tutorials on propagation are at http://k9la.us/.
Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.
Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.
Sunspot numbers for August 21 through 27 were 128, 139, 124, 128,
112, 81, and 82, with a mean of 113.4. 10.7 cm flux was 128.3,
126.4, 132, 140.9, 135, 128, and 123, with a mean of 130.5.
Estimated planetary A indices were 11, 4, 5, 4, 4, 4, and 20, with a
mean of 7.4. Estimated mid-latitude A indices were 12, 4, 8, 5, 4,
5, and 19, with a mean of 8.1.