ARRL

ARRL Propagation Bulletin ARLP008 (2013)

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 22, 2013
To all radio amateurs 

SB PROP ARL ARLP008
ARLP008 Propagation de K7RA

Average daily sunspot numbers over the past seven days, February
14-20, rose modestly by 27 points to 78.3. Average daily solar flux
was up marginally, only 1.6 points to 105.6. Geomagnetic indices
rose also, with the planetary A index from 5.6 to 6.4, and the
middle latitude A index from 5.1 to 6. This is compared to the
previous seven days, February 7-13 reported in last week's bulletin.

There was a more substantial rise in both solar flux and sunspot
numbers for a recent three days, at 104.7, 112.4 and 113.5 for solar
flux, and 92, 117 and 106 for sunspot numbers. But that turned
around when the sunspot number dropped from 106 to 75 on Thursday,
February 21 and solar flux declined from 113.5 to 108.5.

The predicted solar flux is 105 on February 22-23, 100 on February
24, 95 on February 25-26, 100, 105 and 110 on February 27 through
March 1, 100 on March 2-3, 95 on March 4-14, 100 on March 15-16, 115
on March 17, and 120 on March 18-20, which represents a peak for the
next 45 days.

The predicted planetary A index is 8 on February 22, 10 on February
23, 8 on February 24, 5 on February 25-28, 10 and 8 on March 1-2, 5
on March 3-10, 7 on March 11-12, and 5 on March 13-27.

Over the next month we can look forward to improving HF conditions
as we progress toward the Spring Equinox, which occurs on Wednesday,
March 20 at 1102z.

Using a propagation prediction program such as W6ELprop gives us a
rough idea of what the seasonal improvement might be. Running two
instances of the program simultaneously, once for February 21 and
the other on March 21, but with the same solar flux (I used 107)
allows me to flip back and forth between the results. I did one for
Seattle to Japan, and the 15 meter opening from 2200z to 0030z on
February 21 shows up as a 2130-0500z opening on March 21. Similarly,
a 17 meter opening from 2130-0230z on February 21 stretches to
2030-0500z on March 21.

OK1HH predicts the geomagnetic field as quiet to active on February
22, active to disturbed on February 23, mostly quiet February 24-25,
quiet on February 26-28, quiet to unsettled March 1, quiet to active
March 2, mostly quiet March 3, quiet to unsettled March 4, quiet
March 5-6, mostly quiet March 7-8, quiet March 9, and quiet to
active March 10.

Several news articles, such as
http://www.upi.com/Science_News/2013/02/20/NASA-instrument-sees-giant-sunspot-forming/UPI-80691361403797/
and
http://www.science20.com/news_articles/giant_sun_spot_size_6_earths_grows_48_hours-104269
mentioned a huge growing sunspot group 1678 that might spit out
solar flares.  But this spot is way over on the western horizon
(yes, the right side is referred to as "west" on the Sun) and about
to slip away from view.  It is not geo-effective, which it would be
if it appeared in the center of the visible solar disc.

Jon Jones, N0JK of Lawrence, Kansas (where I was born!) has long
enjoyed working 6 meter E-skip and even DX using very modest and
even compromised antennas. Jon reported on February 16: "Julian,
XE2JS DL68 had a nice 6 meter Es opening to the Midwest Saturday
evening (February 17 UTC). I worked Julian while I was mobile on
highway 40 west of Lawrence, KS EM28 with 58 to 59 signals at 0135
UTC. My 6 meter mobile antenna is a 2 meter 5/8 mag. mount whip
(quarter-wave on 6 meters). Saw ZL1RS worked TI5/N5BEK earlier at
2254 UTC February 16."

Yes, Jon feeds that 2 meter whip directly on 6 meters, no change in
loading or any modification. That distance between him and XE2JS is
a little less than 1,000 miles.

On February 19, Jon reported: "The whip I currently use has a 1.1 to
1 SWR, as-is on 6 meters. Some 2 meter mag antennas don't match well
on 6 and may need to be trimmed. ZL1RS later worked KD5PBR, N5DG,
NW0W and a few other stations on 6 meters around 0230 UTC on Feb.
17. Likely an Es link on to TEP. (Jon means sporadic-E propagation
linked to trans-equatorial propagation. See
http://www.ips.gov.au/Category/Educational/Other%20Topics/Radio%20Communication/Transequatorial.pdf
or
http://www.amateur-radio-wiki.net/index.php?title=Trans-Equatorial_Propagation
for info on TEP).

On February 21 Jon wrote, "Even better, I heard ZL1RS CW on February
20 at 2300 UTC on 50.087 MHz, about a 339 RST. This was on an attic
dipole. I am sure I could have worked him with better antenna."

Jeff Hartley, N8II of Shepherdstown, West Virginia wrote on February
17: "I had limited time due to working 1700Z-0230Z over the weekend,
but found conditions at least on 80, 15 and 10 meters to be
excellent during the ARRL CW DX contest.

"In just a few hours on 80 meters around 0140-0440Z Saturday the
February 16 and 0230-0400Z Sunday, I managed to work 270 QSOs and 67
DXCC countries with a 1/4 wave ground plane. Conditions were overall
the best to Europe I can ever remember in a contest. I was able to
run a steady stream of callers at times, the best I have ever done
on 80. I didn't make any QSOs with central Asia, but the well
equipped big guns did work that area. I was called by C4N in Cyprus
with a huge signal, and also a 4Z5 (Israel), and A65BP (United Arab
Emirates). Russians were generally somewhat weaker than western
Europe, but many had good signals all the way to the UA4 area. Big
guns RU1A and RL3A were well over S9! ZS1EL also called me as well
as about 3 or 4 five-watt European stations. At least 3 PY stations
also called in from southern Brazil. The omni-directional antenna
does have a few advantages. Activity from Europe was very good even
the second night when traditionally it is very slow. I also noticed
that some far western USA stations were working Europe as well.

"10 meters was very interesting with marginal conditions to Europe
Saturday, but OH, LY, YL, and SM were logged. There were a few loud
signals from LZ, F, and EA. Stations in the Caribbean at the same
time were very loud as was CR2X, and Africans 6V7S, CR3A, 3V8BB, and
EA9EU all had very good signals. 15 meters around 1530Z was wide
open to Europe with booming signals. Solar flux was right around
100.

"Sunday, I arrived at the perfect time around 1400Z when 10 meters
was just opening to Europe. East of Poland, propagation was almost
nil except for a weak R7MM, and about 3 weak Ukrainians, but I ran a
big pile-up with a huge number of Germans logged and strong signals
even from SM and LA. All of Europe east of Poland had good
conditions to here in West Virginia at least thru 1510Z when I had
to QRT. Conditions were better than would be expected with a solar
flux of only 103 and K index of 2-3, simply amazing that Europe was
booming in."

On February 19 Jeff wrote: "Last night February 18 (but February 19
based on universal time), T46RRC (Cuban IOTA NA-204) was on 80 and
European signals calling them were down 15-20 db from the levels
over the weekend. They were S9+25-30 dB on 160 Monday at 0230Z, a
really awesome signal! They have been so loud that they have had no
trouble putting a lot from 'mother Russia' into the log, the 17
meter op in the mornings can be heard running stations in Russian,
but will switch over to English when a loud station here QRMs the
Europeans."

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 14 through 20 were 25, 59, 75, 74, 92,
117, and 106, with a mean of 78.3. 10.7 cm flux was 99.5, 100.1,
103.2, 105.5, 104.7, 112.4, and 113.5, with a mean of 105.6.
Estimated planetary A indices were 10, 4, 8, 8, 4, 6, and 5, with a
mean of 6.4. Estimated mid-latitude A indices were 11, 3, 6, 7, 4,
5, and 6, with a mean of 6.
NNNN
/EX