Register Account

Login Help

ARRL Propagation Bulletin ARLP049 (2011)

ARLP049 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 49  ARLP049
From Tad Cook, K7RA
Seattle, WA  December 2, 2011
To all radio amateurs 

ARLP049 Propagation de K7RA

November conveniently ended on the last day of this reporting
period, so now let's examine recent averages.  But first, if you
didn't see them, we had an extra bulletin on Monday morning, and
last week's bulletin was a day early.  You can find them archived at  Monday's
Propagation Forecast bulletin ARLP048 is especially important if you
keep a record of solar data, because it corrects 18 bad sunspot
numbers in bulletins 42, 43, 44 and 45.  This was due to errors
generated as they shift to a new system at NOAA. The corrected
numbers have also been uploaded to in the Updated Data File.

The current Cycle 24 continues its upturn. We have a new high for
the trailing three month daily sunspot number average.  Starting
with the three month period ending in December 2010, through
November 2011, they were 30.1, 35.3, 55.7, 72.3, 74.4, 65.9, 61.5,
63, 79.6, 98.6 and 118.8. There hasn't been a three month period
with average daily sunspot numbers above 118.8 since way back in
June, July and August 2003, when the average was 121.9. This was as
Cycle 23 was declining.

The monthly averages of daily sunspot numbers for August through
November 2011 were 66, 106.4, 123.6 and 133.1.

The latest forecast from NOAA/USAF has solar flux on December 2 at
145, 140 on December 3-5, 135 on December 6-7, 140, 150, 150 and
155, on December 8-11, and 160 on December 12-18, then 155 on
December 19-22.  Planetary A index on December 2-10 at 8, 8, 7, 8,
8, 5, 5, 8 and 8, then 5 on December 11-22. Look to for a daily
update of this forecast.

Geophysical Institute Prague sees unsettled conditions on December
2, quiet to unsettled December 3-5, and quiet conditions December

Conditions may not be as quiet as we would like (in terms of
geomagnetic disturbances) for the ARRL 160 Meter CW Contest this
weekend, but no major disruptions are anticipated either. Instead of
the predicted planetary A index of 8 or 7, we would prefer a
forecast with an A index of 5, or lower.  With conditions so quiet
over the past few years, 160 meter operators had some great
conditions to work with. For months at a time the NOAA/USAF forecast
would show planetary A index of 5 (for some reason it is never
predicted lower than that), and mail from 160 meter operators
praised the absence of solar activity that most HF operators

Although conditions at lower and middle latitudes were fairly quiet,
on Wednesday, November 30, polar geomagnetic indices were quite
active. You can see it at in the high latitude
college A and K index at University of Alaska, Fairbanks. They have
a nice web page devoted to geomagnetic activity at They have a nice Auroral
Activity by Solar Rotation display (click on it to make it bigger),
and each line represents a complete rotation of our Sun, with a
range of dates covering 27-28 days. The display shows some recurring
activity, and currently you can see a spike of geomagnetic activity
from September 26-29 coming around again on October 25.

To check the readings on those dates, look at the quarterly records

Historical indices going back to 1994, including sunspot numbers and
solar flux, are at

Daily reports at give us some
insight into what caused a disturbance on November 30. The report
for that day says "The geomagnetic field reached quiet to active
conditions with minor and major storm periods observed at high
latitudes.  Activity was attributed to a solar sector boundary
crossing (SSBC) at approximately 30/0810Z followed by a prolonged
period of southward Bz in the interplanetary magnetic field."

For information on what they mean by "solar sector boundary
crossing," see

WA8IWK, Allen Olender of West Bloomfield, Michigan sent a nice note
relating his joy over recent HF conditions: "I've spent more CW time
on 10 meters working amazing DX in the past 2 months than I have
spent on that band in the past 48 years combined!!  All with a
mobile antenna in my attic!  A great time for our hobby!"  You can
see a nice photo of Allen with some Boy Scouts at, but these days you must log in to that

Jeff Hartley, N8II of Shepherdstown, West Virginia sent a detailed
report on his 10 meter single band effort for the CQ Worldwide CW
Contest last weekend.

But first, "On Tuesday (November 22), I logged T6MO (K9GY) in the
U.S. Army (Afghanistan) on 10 CW at sunrise. He was running 100
watts to a G5RV dipole, nice opening, but it was not to be as good
during the CQ WW."  Check for info on

And for the contest, "On Saturday, I turned on the radio at 1130Z
about 45 minutes before sunrise to find many 10 meter signals.
Africans were S9+ and quickly logged D4C and C5A. Europeans were
louder at about 100 degrees scatter path but by and large were loud
enough that they could hear me calling. Right around sunrise the
band opened direct path to EU and I started my best 5 hours of EU
running ever, averaging about 130-140 QSOs per hour. Signals from
eastern EU lasted until around 1500-1530Z. Activity was tremendous
from EU!  The Ukrainian turnout was tremendous as was the activity
from YO, OK. Conditions to the Moscow area were OK, but not nearly
as good as a month ago. During the weekend, 257 QSOs were made with

"By about 1715Z darkness had pretty well closed the band except for
some loud EAs, Fs, and Is. Africa and stations very close to the
south (Cuba, Cayman Is., Turks & Caicos) to far away were loud.
During the contest ST2, C9, CN, CT3, C5, D4, EA8, EA9, EL, ZS, ZD8,
5X and 9L were logged from Africa. ZM4T was the first New Zealand
worked in the 17Z hour (5AM in ZL), KG6DX was booming in around
2040Z for first QSO of 4 with Guam, they were uniformly S9+ until
about 23Z, as was AH0BT. Unfortunately, a really good JA opening
never materialized with Saturday being the better day, only 55 JAs
were logged total. Surprisingly, three VKs in zone 29 were logged.
Other Pacific DX logged was TX8, ZK2, KH7, and E51MAN. JAs faded out
at 2315 and by 2330Z the band was nearly dead.

"Sunday, 10 meters was a bit slower to fully open to EU, but first
direct path signals arrived around 1210. UP0L in Kazakhstan was
logged scatter path. I worked my first zone 21s (A7 and HZ) and was
called by VU2KMS around 14Z. The EU opening lingered until around
19Z to very southern/western EU, but QSO volume was minimal past
about 1630Z. OH6AC was logged close to 19Z. Four total TFs were
worked including a mobile and OX3XR was worked around 21Z. Alaskans
were loud both days for hours, but not many casual ops from there
were active. Around sunset both days was the end of working much of
anything to the south. JAs were very poor Sunday with only about a
15 minute window when the big guns were moving the S meter.

"We still have room for improvement (higher solar flux), but 10 and
12 meters have been loads of fun since late September. The ARRL 10
meter contest should be a pretty major event on December 10-11."

Details on the upcoming ARRL 10 Meter Contest are at  This year there are some new
multipliers for working states in Mexico. A map showing states in
Mexico along with which are rare or easy is 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 November 24 through 30 were 139, 171, 133, 123,
90, 106, and 111, with a mean of 124.7. 10.7 cm flux was 137.2,
135.2, 132.8, 135.2, 137.6, 140.6, and 144, with a mean of 137.5.
Estimated planetary A indices were 5, 4, 3, 6, 4, 9, and 10, with a
mean of 5.9. Estimated mid-latitude A indices were 4, 3, 4, 5, 7, 9,
and 9 with a mean of 5.9.


Instragram     Facebook     Twitter     YouTube     LinkedIn