ARRL

ARRL Propagation Bulletin ARLP008 (2012)

SB PROP @ ARL $ARLP008
ARLP008 Propagation de K7RA

ZCZC AP08
QST de W1AW  
Propagation Forecast Bulletin 8  ARLP008
From Tad Cook, K7RA
Seattle, WA  February 24, 2012
To all radio amateurs 

SB PROP ARL ARLP008
ARLP008 Propagation de K7RA

We don't know if this is a significant trend, but solar activity has
really leveled off recently. Not everyone is unhappy about this.
During the recent long minimum, 160 and 80 meter operators sang the
praises of great conditions.

In response to my "we hope it isn't true" (prediction for a low
solar cycle) comment in last week's bulletin, Ken Meinken, WA8JXM of
Aberdeen, Ohio wrote: "Why would that be bad?  You are showing your
20-15-10m bias.  To those of us who prefer 160/80/40, the lower the
sunspots, the better.  Personally, I prefer the low part of the
sunspot cycle to the peak.  Of course I understand that other hams
have various different opinions."

The average indicators this week were almost exactly the same as
last.  Average daily sunspot number rose from 55.6 to 55.7. The
average daily solar flux declined 2.6 points to 105, and in an
unusual coincidence the planetary A index and mid-latitude numbers
were the same this week as last, 8 and 6.7.  For the numbers at the
end of the bulletin, and had to check three times to make sure I
hadn't just copied last week's numbers.

The geomagnetic activity was concentrated around February 19-20, and
was the result of a solar wind stream, causing aurora visible in the
lower 48 states.

Tim Goeppinger, K6GEP of Orange, California reports an amazing 10
meter aurora opening between the West Coast of the U.S. and
Scandinavia last Saturday night, February 18,

The latest prediction shows solar flux at 105 on February 24-25, 100
on February 26-29, 105 on March 1, 100 on March 2-4, 105 on March
5-11, 110 on March 12-13, and 115 on March 14-19. The prediction
sees planetary A index at 5 on February 24 through March 1, 8 on
March 2-3, 5 on March 4-6, 8 on March 7, and 5 on March 8-10.

Jeff Harley, N8II of Shepherdstown, West Virginia wrote on February
18, "10M has been open to EU most days here recently, but nothing
like the Oct-Dec openings. In the PACC Dutch contest last weekend,
Dutch stations were worked as early as 1330Z and as late as about
1645Z with the best conditions around 1620-1640Z. I worked a total
of about 27 PA-PI stations on 10 meters and 20 was open past 2030Z,
but most Dutch stations migrated down to 40 and lower quite early.

"This weekend was a salt mine weekend, so time was limited in the
ARRL CW. I stayed on 20M and worked what I could working about 132
QSOs in 31 countries in about 2-1/2 hours between 0030Z-0315Z.
Conditions over the pole were very good, my very first CQ was
answered by a BA1 station and BV1EH, 9V1YC, E21EIC and another E21,
UN7, two HLs, many JAs, and many zone 18 and 19 Siberian Russians
all answered CQs. The increased polar daylight is improving and
lengthening the 20M polar openings. The band was open well to the
Caribbean at first and Africa and even CS2C in Portugal was worked.
Also the big gun OH8's and one LA2 were logged.

"Saturday morning, 20 was wide open to EU by before sunrise and also
open to Zone 17 and 18 in Russia with signals from there having a
wicked flutter. Two HS0s called in and signals stayed very strong
from EU until around 14Z. Then I checked 10M which was open to areas
very unexpected/poorly explainable for a SFI of only 103. UA1AFT
running 5W was about S6, another loud RA1, several OHs, SM, OZ, LY,
YL, ER, UR were all logged. Some of the best signal were from
Poland, but Germany just to the west was marginal as were Gs and
ONs. Many OKs and Is were logged, but at times even the Is were
somewhat weak. Around 1530, the Balkans big guns S5, 9A, E7DX were
S9+. My 10M CQ QSO rate was never very high, but there was fairly
steady stream of stations. Signals from the Caribbean farther south
than ZF were generally S9+."

Thanks, Jeff.

Julio, NP3CW wrote: "Last night Feb 22, 2012 I was able to contact
CP6UA on 50.115 MHz after been looking for him for long time . This
is my new one for 124 entities worked. It was a nice contact from
FK68wl to FH82ue. It took me nearly 10 yrs to complete all South
America Countries. Recently also worked HK0NA on 6 meters, Enrique
told me he will soon get a 1 KW amplifier for 6 meters, so maybe
more stations can work him in North America. Today Feb 23 2012 many
stations heard strong in PR on 6 meters from LU, CX, and PY. Among
them were CX1DDO, LU2DPW, PY2LED, CX6DH and PY1RO."

CP6UA asked if there are any propagation prediction programs that
work for 6 meters.  I was pretty sure there are none, but I inquired
with Carl Luetzelschwab, K9LA for comments.

Carl wrote: "None of our propagation prediction programs cover 6
meters - they stop at 30 MHz. The reason why is the extremely
dynamic nature of the F2 region, which varies widely on a day-to-day
basis due to other factors than solar radiation. Thus our
understanding of the F2 region is statistical in nature over a
month's time frame, and this ultimately results in extremely low
predicted probabilities for 6 meters since the frequency is so high.
Coupled with this is the fact that 6 meter propagation may not be
simply refraction - it may involve scatter, help from the underlying
E region, and some other things."

Carl has an article on predicting 6 meter F2 propagation, which you
can read at,
http://myplace.frontier.com/~k9la/Predicting_6_Meter_F2_Propagation.pdf.

In the ARRL Letter we promised some comments by K9LA on recent solar
activity trends, but that will have to wait. Carl ran some smoothed
solar flux numbers for Cycles 19-23, to observe any double-peaks,
and noted: "Cycle 19 didn't have a second peak (it didn't need
one!).

"Cycle 20 might have had a second peak - hard to tell.

"Cycle 21 had a definite second peak.

"Cycle 22 also had a very nice second peak.

"And Cycle 23 had a second peak that showed considerably more 10.7
cm radiation than the first peak. That was a blessing for 6m DXers
in the winter of 2001."

And finally, we haven't mentioned this site in awhile, for info on
Space Weather Basics:
https://www.meted.ucar.edu/training_module.php?id=901.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

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
http://myplace.frontier.com/~k9la/.

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 February 16 through 22 were 41, 53, 63, 69, 72,
61, and 31, with a mean of 55.7. 10.7 cm flux was 103.2, 103.7,
104.1, 105.3, 111.1, 103.3, and 104.2, with a mean of 105. Estimated
planetary A indices were 4, 2, 4, 16, 16, 6, and 8, with a mean of
8. Estimated mid-latitude A indices were 4, 2, 3, 11, 14, 4, and 9,
with a mean of 6.7.
NNNN
/EX