Propagation Forecast Bulletin #40 de K7RA:
W1AW Bulletin via the ARRL
October 4, 2013
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Propagation Forecast Bulletin #40 de K7RA:
QST de W1AW
Propagation Forecast Bulletin 40 ARLP040
>From Tad Cook, K7RA
Seattle, WA October 4, 2013
To all radio amateurs
SB PROP ARL ARLP040
ARLP040 Propagation de K7RA
Solar activity weakened again, with the average daily sunspot number
dropping from 75.6 to 52, and average daily solar flux down three
points to 106.6, when compared to the previous week, September
Geomagnetic activity was up, with planetary A index at 39 on October
2, mid-latitude A index at 29, and the high latitude college A index
The cause of the upset was a coronal mass ejection barreling toward
Earth at 2,000,000 MPH on September 30, triggering a G2 class
geomagnetic storm on October 2 and aurora displays well south of the
Predicted solar flux values are 110 on October 4-5, 105 and 100 on
October 6-7, 95 on October 8-13, 100 on October 14-15, 105 on
October 16-18, and 110 on October 19-24.
Predicted planetary A index is 20 on October 3, 8 on October 4, 5 on
October 5-9, 8 on October 10-11, 5 on October 12-13, then 8, 10 and
8 on October 14-16, 5 on October 17-20, 10 on October 21, and 5 on
OK1CC predicts a quiet to unsettled geomagnetic field on October 4,
mostly quiet October 5, quiet on October 6, quiet to active October
7-10, quiet to unsettled October 11, quiet on October 12-13, quiet
to active October 14, active to disturbed on October 15-16, quiet to
active October 17-18, quiet October 19-20, active to disturbed
October 21, mostly quiet October 22, quiet October 23-27, quiet to
active October 28, and active to disturbed October 29-30.
I've been keeping an archive of the 45-day solar flux and planetary
A index predictions from NOAA/NASA, and it is interesting to see how
they change over time. Conditions 30-45 days out must be pretty hard
to predict, but I've noticed that the outlook seems to be
increasingly pessimistic recently, suggesting weakening sunspot
For instance, the 45 day prediction for September 16 began on August
2, with a solar flux of 125. Then over time it drifted around,
within a few days down to 105 (August 5-11), then back up to 125 on
August 19-25, then the prediction begins to wither to 115 August 26
to September 8, declining again to 100 (September 9-12), then in the
few days before the target date September 13-15 at 95, which was
right on the nose with the end result being 94.5. This of course
rounds up to 95, the whole number used in the prediction.
I keep seeing predictions with solar flux values dropping below 100,
even down to 90. Take a look at,
You can also see my own longer term archive in spreadsheet format at
http://snurl.com/27xfhcg. Password is k7ra. This particular archive
goes back to April 19.
The column on the left shows the dates of the forecasts, and across
the top are the dates that the data correspond to. The numbers in
blue across the bottom are the actual flux values recorded on the
dates for each column, or when the column and row intersect on the
A similar spreadsheet for the planetary A index can be downloaded
http://snurl.com/27xfgtc. Same password, k7ra.
Today we have an addition to our three-month moving average data
set, and I am now convinced that we may have already passed the now
classic double-peak for Cycle 24 that some have predicted based on
activity in previous cycles. As others have suggested, those peaks
seem to be clearly centered around October to November 2011, and
April to May 2013. For the 3-month period ending September 30 the
average was 77.4
Starting from a three month average centered on January 2011 (data
from December 1, 2010 through February 28, 2011), averages for that
year were 35.3, 55.7, 72.3, 74.4, 65.9, 61.5, 63, 79.6, 98.6, 118.8,
118.6 and 110.
For 2012 it was 83.3, 73.7, 71.2, 87.3, 91.5, 96.5, 91.9, 89.9,
81.2, 82.3, 74.4, and 82.8.
So far in 2013 the averages are 73.6, 80.7, 85.2, 106.4, 106.4,
97.5, 85.6 and 77.4.
Some solar scientists suggest a possible subsequent peak in 2014. I
certainly hope so, but have no way of knowing. Our nearest star
remains baffling and full of surprises. The body of knowledge and
available tools expanded tremendously over the past couple of
decades, yet accurate predictions elude us. Remember a few years ago
when one of the more optimistic scientific papers suggested a
record-breaking Cycle 24, perhaps approaching the levels of Cycle 19
in the late 1950s? The future looked bright.
There is this interesting theory that the first cycle following the
beginning of any century is weak. Could there also be a 100 year
recurrence of Cycle 19? Tell your children or grandchildren. That
would be over a century after my birth, and planning for it now
would be a fool's errand.
Thanks to Jimmy Mahuron, K9JWJ for reminding us about the 2007 book
by Stuart Clark, "The Sun Kings: The unexpected tragedy of Richard
Carrington and the tale of how modern astronomy began." I suggested
it in this bulletin several years ago, checked it out from the
library, but it joined the tall stack of non-fiction to read and I
finally returned it. I just reserved it again, and if you happen to
be in Seattle, I see it is currently on display at the Green Lake
Branch of Seattle Public Library. I guess that our librarians
selected a number of books about astronomy or the Sun for a themed
display, but these are never locked in display cases. These books
can be picked up, perused and even checked out.
Jimmy also noted on September 27 that 40 meters was good for him the
previous Saturday, September 21.
Emil Pocock, W3EP reported on September 29, "It is a bit early in
the Fall DX season and solar activity is still low, but 10 meters
has come alive. The band opened to Western Europe at the unusually
late time of 1920-2000 (I assume he means UTC, rather than local
time) September 13. There were teaser openings to Europe on the
mornings of September 17, 18, and 21. I was surprised to work
3B8/G0TSM on the September 18 among the European callers.
"The first significant opening from here in Connecticut was on
September 22 and then every morning to September 29. Eastern
European stations dominated, especially UR and UA. Interesting
stations worked included FR5FC, HZ1SK, FH4VOS and OD5ZZ on September
24, all on SSB. The following day, snagged on CW 5A1AL and SU9AF. On
September 25, logged 4Z5SG, 4Z5ML, ZA1G, 4K9W and UP5OA. Stations
worked on the September 27 included some real surprises, including
EW8O and EW3AN (EW not worked on previous days), but also VU3KPL and
XV4Y. XV4Y was worked on direct path over the pole. What a thrill to
hear Vietnam through the European callers! Eastern Europeans
continued to dominate QSOs on September 28 and 29, including UA9XO.
"Hope this bodes well for the rest of the Fall season, even if solar
activity remains sluggish."
Hope so too, Emil, and thanks for sending an uplifting counterpoint
to my gloomy assessment earlier in this bulletin.
Jim Smith, K3RTU of Aston, Pennsylvania wrote on October 2 about
another hike in one of his favorite parks, taking along a portable
HF radio and antenna, of course: "Despite the less than desirable
predicted solar flux for Monday September 30, I went on a hike in
Ridley Creek State Park here in Southeast Pennsylvania (FM29). In
one of my favorite spots I tried a different antenna instead of my
trusty Buddistick vertical. I was using an end fed wire of 30' with
a 9:1 UNUN matching transformer. I got the end of the wire up into a
tall tree at about a 50 degree angle and attached the other end with
the matching transformer to a plastic tent peg. Then I ran the coax
back to my KX3. I was running the KX3 with AA lithium batteries so I
kept the power cut back to just under 3 watts. Even with this less
simple setup I was able to work CO0CW in Havana and received a RST
of 579 at about 1540 UTC on 17 meters. I wasn't hearing many
station, however, so I tried 15 meters. I was delighted to then work
SM5NZG near Stockholm at about 1620 UTC. I only received an RST of
539 from Heide, but was still able to chat for about 10 minutes.
Heide's 6 element Yagi was obviously doing the heavy lifting, but it
was still good to see that less than 3 watts from a simple end fed
wire could make the trip across the Atlantic even without much help
from the Sun."
Thanks to Max White, M0VNG in the UK for this interesting piece on
some space weather research:
And finally, Jeff Hartley, N8II of West Virginia wrote to us last
evening, "Conditions on September 27-30 were good on the high bands
with October 2 being the poorest day. Throughout the period the SFI
ranged from low 100's to around 115.
"On September 27, 12 meters was open well to Europe by 1300 UTC
(sunrise is just after 1100 UTC, sunset around 2345 UTC) working
many Ukrainians. By 1330 UTC, 10 meters was open to southern Europe
and especially the UA6 area and Ukraine. At 1500 UTC, JW9JKA on Bear
Island, EU-027 was easily worked S5 on 10 phone followed by OZ1BTE,
OH5UZ, several Germans, Polish, Austrians and a few Southern
Europeans, mostly with S7-S9 signals going QRT at 1533 UTC. Andy,
UA0BA was found on my return at 1828 UTC a solid 599 on 10 CW from
far northern zone 18, which is well after midnight there, with some
auroral Es probably involved. Then I found him on 12 meter CW at
1846 UTC about 559. Both UA0ZC and R0FA were loud on 12 CW at
2103/2124 UTC, but the band every day seems to close to Asia by
sunset. About an hour after sunset RA/KE5FA, HL2XUM, and DU2US were
around S5 on 17 CW.
"On September 28, my first morning QSO was UA9FAR on 12 meter CW,
and he was 589. By 1318 UTC, 10 meters opened to RA1QD and YL2TQ.
DXing took a back seat to the Texas QSO Party for most of the rest
of the weekend. 20 meters was in pretty good shape to Texas most of
the time except Sunday after about 1730 UTC when absorption was
high. 15 meters opened to Texas well by about 1540 UTC both days and
stayed open until past 2230 UTC Saturday, but activity could have
"10 meters opened on Sunday well to Europe at 1308 UTC when I turned
on the radio, with many UA3 area stations logged. Conditions
actually seemed to favor Russia with about 25 stations logged before
QRTing for the Texas QSO Party at 1352 UTC; western EU was weak at
best. This was the best day into Russia and surprisingly good
conditions considering the fairly low SFI.
"On September 30, 10 meters did not open well to Europe, but again
there was some propagation to RU3EG (1506 UTC) and UA3YDH (1335
UTC). And surprisingly, Kumar, VU2BGS was worked S5 on 10 CW using a
6 element yagi on his end and 5 el on my end. Twelve meters was open
well to UR and Russia as far as RQ4F. Outside of India, Central Asia
conditions have not been good above 20 meters. 8Q7AM was 57 on 15
meter phone at 1653 UTC, but he is far south. Since October 2, 10
has sounded poor except to the south and even 12 meters has been
quite poor or closed to Europe.
"Today, Oct 3, conditions seemed to improve later in the day with a
good 12 meter opening to JA around 2220 UTC and a good signal from
TO2TT on Mayotte in the Indian Ocean on 17 phone at 1942 UTC. There
was some sporadic-E into New England as well as to county activator
W0GXQ in eastern Oklahoma, logged on 12 and 10 meters with S5
signals or better (1540-1722 UTC) and still loud on 15 most of the
time on F2 thru 2046 UTC."
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
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. More good
information and tutorials on propagation are at
Monthly propagation charts between four USA regions and twelve
overseas locations are at
Sunspot numbers for September 26 through October 2 were 63, 54, 58,
39, 42, 49, and 59, with a mean of 52. 10.7 cm flux was 109.9,
107.9, 105.7, 103.1, 104.9, 106.8, and 108.1, with a mean of 106.6.
Estimated planetary A indices were 2, 2, 2, 3, 3, 5, and 39, with a
mean of 8. Estimated mid-latitude A indices were 2, 2, 2, 3, 3, 6,
and 29, with a mean of 6.7.
Source: W1AW Bulletin via the ARRL.
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