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ARRL Propagation Bulletin ARLP037 (2012)

ARLP037 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 37  ARLP037
From Tad Cook, K7RA
Seattle, WA  September 14, 2012
To all radio amateurs 

ARLP037 Propagation de K7RA

Solar activity retreated this week.  Average daily sunspot numbers
were off nearly 46 points, or about 35%, to 83.1.  Average daily
solar flux declined 18 points to 118.9.

Geomagnetic conditions were quieter, with the planetary and
mid-latitude A index most days in the single digits.  Average
planetary A index declined from 14.1 to 6.6.

The predicted daily solar flux is 100 on September 14-15, 95 on
September 16-18, 98 on September 19, then 100, 95 and 100 on
September 20-22, 110 on September 23-24, then 115, 125 and 130 on
September 25-27, 140 on September 28 through October 1, 135 on
October 2, and 130 on October 3-5.

The Predicted planetary A index on September 14-17 is 7, 10, 15, and
10, then 5 on September 18-19, 8 on September 20-23, 5 on September
24-28, 10 on September 29, 5 on September 30 through October 2, 10
on October 3, and 8 on October 4-5.

F.K. Janda, OK1HH of the Czech Propagation Interest Group predicts
quiet to unsettled geomagnetic conditions September 14-15, active to
disturbed September 16, mostly quiet September 17, quiet on
September 18, quiet to unsettled September 19-22, mostly quiet
September 23, quiet September 24-25, quiet to unsettled September
26-27, quiet September 28-29, quiet to active September 30 through
October 1, active to disturbed October 2, and quiet to active
October 3.

In VHF news, Rich Zwirko, K1HTV in Amissville, Virginia wrote to us
on September 7, just before the ARRL VHF Contest last weekend: "I
was pleasantly surprised to hear 6 meters open via TEP to South
America early Thursday evening, September 6. It started around 2240Z
and lasted about an hour at my FM18ap QTH in VA. In addition to
working PY1RO, PY1NX and PY2XB on CW I also heard but did not work
LU9EHF and PY1NS weakly on SSB. There is still some magic in the
'Magic Band.'"

TEP refers to Trans-Equatorial Propagation, a special kind of
propagation across the equator.  A good description from the
Australian Government Radio and Space Weather Services can be
downloaded at

Just before we put this bulletin to bed, K1HTV sent this: "Here is
some additional info. During last weekend's ARRL VHF contest I heard
3 stations in Brazil on 6 meters. I worked PY5EW on SSB and PY2XB on
CW. Also heard PY1RO weakly on SSB but couldn't work him. The 50 MHz
TEP path between my FM18 Virginia QTH and the PY stations, in the
GG46 and GG66 grids, started around 0005Z September 10 and lasted
about 1 hour. Unfortunately no other South American stations were
heard. About 24 hours earlier in the contest, starting around 000Z
on the September 9, we had a 90 minute Es opening to W5 land,
working stations in OK, MS, LA and TX. Again between 1330 and 1500Z
Sunday there was a 6M ES opening from here to Florida. So, as you
can see, the 'Magic Band' is still not dead!"

Rich hopes for a double-peaked Cycle 24, and that the solar activity
will be enough to send the MUF on many paths above 50 MHz.  Of
course, in that case, instead of just sporadic-E we would see
conventional F-layer ionospheric propagation.

John Jones, N0JK of Lawrence, Kansas wrote: "The jump in solar
activity coupled with some sporadic-E on 6 meters created
opportunities for some great propagation in the ARRL September VHF
QSO Party (September 8-10, 2012).

"Both Saturday and Sunday had extended openings from New England,
mid-Atlantic, Gulf Coast, Arizona and California to South America
and the South Pacific. On Sunday, KA9CFD EN40 spotted PY2XB at 0054
UTC September 10. And what may have been direct F2 from Florida to
Ecuador Sunday occurred that afternoon.

"Some Es Saturday evening from Kansas to Georgia, when W3GMT EM92,
WA4NJP EM84 and W4IMD EM84 were loud around 0035 UTC September 8."

John closed by saying he also hopes for a double-peaked Cycle 24.
More about that in comments from K9LA further down.

Jeff Hartley, N8II in West Virginia wrote on September 9: "Today was
a pretty good day on 15 and 10 meters with the solar flux only in
the 120s, definitely better than Saturday (September 8) with only
South America on 10 meters. At 1451Z, I logged XV4Y (Viet Nam) on 15
CW who was running a EU pile up, I could not get thru until he
worked a N2 then started a CQ NA only. Then I tuned 10 meters
looking for some EU in the WAE (Worked All Europe) contest and heard
a voice with polar flutter giving a contest report to an inaudible
EU. I swung the Yagi north and 9W2VVH (Western Malaysia class B
license) answered my SSB CQ at 1458Z. He gradually got stronger and
went up to S7, running 100 watts, once he beamed to USA. After a few
more CQs 9W2WWW answered and was equally as strong. 9W2AXV and
9W2NMX also answered CQs. It was in the 11:00 PM hour local time in
9W2 when the band peaked.

"No other Asians were worked, but after a dog walking break and
lunch around 1700 to 1815Z, 10 opened to EU with some weak and some
loud signals from central and western EU, but no propagation to
Russia or northern EU. I worked 50 stations in 14 EU countries in
the WAE contest, quite late in the day.

"NH8S was about S6 on 10 phone and CW around 10 minutes past sunset
sunset was around 2325Z at Jeff's QTH and logged fairly easily,
then worked him on 12 SSB at 2348Z about S5."

K9LA, Carl Luetzelschwab, has some interesting comments about last
Fall not being the first peak of a double-peaked solar cycle.  Last
week we mentioned that the NASA estimate has move the peak of Cycle
24 from Spring to Fall 2013, with smoothed sunspot numbers higher
than earlier forecasts.

Carl wrote, "The smoothed data (whether it be the smoothed sunspot
number or the smoothed 10.7 cm solar flux) does not indicate a Cycle
24 peak in the Fall of 2011.

"What happened was the Sun was very active for a couple months, and
this was fortuitously in the Fall months when the MUF is the highest
in the Northern hemisphere. The MUF reached over 28 MHz, which gave
us great worldwide 10-Meter openings in the CQ World Wide DX
contests and the ARRL 10-Meter contest. After that solar activity
waned, the MUF fell, and 10-Meters wasn't as good for the ARRL DX
and CQ WPX contests in the less-than-optimum months.

"Historically a true peak would be followed by a definite dip in the
smoothed indices prior to reaching another peak. Cycles 22 and 23
exhibited this classical behavior. But Cycle 24 just had a
leveling-off (as have other solar cycles on their ascent) before
continuing its ascent.

"So we're still waiting for the first peak of Cycle 24. Whether it
has a second peak is anyone's guess."

And finally, for an interesting video visit to the McMath-Pierce
Solar Telescope at Kitt Peak, check it out 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 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 September 6 through 12 were 112, 110, 70, 87,
62, 73, and 68, with a mean of 83.1. 10.7 cm flux was 128, 133.4,
128.6, 123, 111.3, 105.1, and 102.6, with a mean of 118.9. Estimated
planetary A indices were 11, 9, 8, 5, 4, 3, and 6, with a mean of
6.6. Estimated mid-latitude A indices were 12, 8, 7, 6, 4, 3, and 5,
with a mean of 6.4.


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