ARRL

ARRL Propagation Bulletin ARLP039 (2013)

SB PROP @ ARL $ARLP039
ARLP039 Propagation de K7RA

ZCZC AP39
QST de W1AW  
Propagation Forecast Bulletin 39  ARLP039
From Tad Cook, K7RA
Seattle, WA  September 27, 2013
To all radio amateurs 

SB PROP ARL ARLP039
ARLP039 Propagation de K7RA

Our sun is still very quiet, but solar flux and sunspot numbers were
higher this week than last.  Average daily sunspot numbers rose from
42.3 to 75.6, and average daily solar flux rose from 95.3 to 109.6.
There were no big geomagnetic events this week.
 
Predicted solar flux is 110 on September 27 through October 2, then
105, 100, 95, 100, 105 and 100 on October 3-8, 95 on October 9-10,
then 100, 105 and 100 on October 11-13, 95 on October 14-15, and all
the way down to 90 on October 16-19.
 
Predicted planetary A index is 5 on September 27-28, then 8, 10, 12
and 8 on September 29 through October 2, 5 on October 3-9, 8 on
October 10-11, 5 on October 12-13, then 8, 10 and 8 on October
14-16, and 5 on October 17-19. This is unchanged from the forecast
in Thursday's ARRL Letter.
 
F.K. Janda, OK1HH of the Czech Propagation Interest Group predicts
active to disturbed conditions September 27, quiet to active
September 28, mostly quiet September 29, quiet on September 30,
quiet to active October 1, quiet October 2-5, quiet to unsettled
October 6-7, mostly quiet October 8, back to active to disturbed
conditions October 9, as it was on the first day of this forecast.
 
David Moore, a shortwave listener in Moro Bay, California is a
frequent contributor here, and sends a New York Times article titled
"The Sun That Did Not Roar", about our current quiet sun.  In
reference to a weak solar event last week, it characterized a CME as
what "seemed like the halfhearted effort of a slacker star." See it
at http://nyti.ms/1fd48GT .
 
But 160 meter operators are not despairing a dearth of solar
activity to come, as more solar activity correlates with higher
geomagnetic activity, and they like things nice and quiet.
 
Often the declining years of a solar cycle are marked by heightened
geomagnetic activity (see http://www.spacew.com/gic/guidance.pdf for
a treatise on this) and I can recall times during the decline of
cycle 22 in the 1990s when it seemed like geomagnetic disturbances
were constant.  Although the record in its most easily accessible
form doesn't go back as far as we would like, check out this
geomagnetic index record from 1994:
 
http://www.swpc.noaa.gov/ftpdir/indices/old_indices/1994_DGD.txt
 
Check out February 5-15, February 21-22, March 3, March 7-21, April
1-18 (especially April 17, with a huge planetary A index of 130!),
May 1-17, May 28-31, Jun 25 to July 7, September 7-10, October 3-7,
23-24, and 29-31, and November 26-27. Note the very large planetary
A index values throughout the year, and this represents week after
week buffeted by high absorption and even radio blackouts. As if
this wasn’t bad enough in the middle latitudes, I recall Vince Van
Der Hyde, K7VV was living in Alaska at the time (possibly near the
65th parallel) and told me later that his favorite HF bands were
unusable for months at a time, due to the concentration of
geomagnetic energy toward the poles.
 
In the table above, check out the College A index, which is measured
near Fairbanks at the University of Alaska. It is in the middle
column. See all those asterisks where there should be numerals?
Those are periods when the magnetometer was unusable due to being
swamped with too much energy from a coronal mass ejection, for
instance. Now compare the numbers in 1994 to more recent readings:
 
http://www.swpc.noaa.gov/ftpdir/indices/old_indices/2012_DGD.txt
 
http://www.swpc.noaa.gov/ftpdir/latest/DGD.txt
 
There are a few relatively high numbers, but nothing like what we
observed and sometimes suffered with two decades ago.
 
A glance at this graph shows how far down we were on cycle 22 during
1994:
 
http://standeyo.com/Geo_Solar/Solar_Cycles_22_23/cycle_22_review_01.gif
 
By the way, the exact location for the magnetometer which generates
the college A and K index is at 64.8742 degrees North latitude and
147.8597 degrees West longitude, roughly one half mile northeast of
Smith Lake, 400 yards south of Yankovich Road, and one half mile
east of Miller Hill Road in Fairbanks. This is about 117 miles or
188 km south of the Arctic Circle.
 
You can see photos of the geomagnetic observatory at 
http://geomag.usgs.gov/monitoring/observatories/college/#photos and
also at 
http://www.bing.com/maps/default.aspx?cp=64.8742|-147.8597style=hlvl=17

Note on the overhead view on Bing Maps you can zoom in, and by
clicking on Aerial, then the Bird's Eye dropdown you can see highly
detailed images from four different directions. Just click on the
arrows outside the compass rose in the upper right to see the
observatory from a point of view in each direction.
 
Dave Greer, N4KZ of Frankfort, Kentucky wrote about 10 meter
openings on the autumnal equinox, last Sunday.
 
"Ten meters was open to southern Europe and South Africa on the
morning of September 22, the first day of fall. For the past couple
of weeks, various European operators had been telling me on lower
bands after I got home from work that 10 meters had been open to the
States earlier in the day. But I was at work in each instance and
missed out. So I made an effort on Sept. 22 to be on the band and it
didn't disappoint. I copied numerous stations but primarily they
were from France and Spain. I copied a British station but he was
weak. I worked S58WW at 1510 UTC and he had a good signal but not as
strong as others. CU7MD from Azores was copied too but with several
prior QSOs in our logs, I let others work him. ZS3Y from South
Africa had a big signal as did EA8YB in the Canary Islands. But I
passed on them as well because of our previous QSOs on the band."
 
"But my most interesting QSO on Sept. 22 was with F4DSD in France. I
think they call this the 10-meter deja vu mode of propagation
because Mario and I had worked exactly one year earlier.  And I do
mean almost exactly a year ago. Our two QSOs, both on 10 meters on
Sept. 22, occurred in 2012 and again in 2013 and were only 12
minutes apart in time and only 5 KHz apart in frequency. Now that
really is deja vu!"
 
Thanks, Dave. That really must have been an odd feeling and quite a
fun topic of conversation.
 
You may be surprised to hear of 10 meter openings given the paucity
of sunspots, but given seasonal variations, right around the equinox
is the ideal time. Run a projection with a program such as W6ELprop
from Dave's location (38.205 deg N, 84.896 deg W) to France, for
instance, and on September 22 with low sunspot or solar flux
numbers, we can see some possibilities for openings around 1530-2100
UTC, and especially between 1900-2030 UTC. But change the date back
or forward a month or two, and the opening disappears.
 
More mail on 10 meters, from Rol Anders, K3RA in Elkridge, Maryland:
"Ten has been opening to EU from Maryland more and more, starting in
mid September. I worked IW1CHX on September 11 at 1438 UTC on CW.
The KD4D team at N3HBX worked 54 EU stations on Sunday of the WAE
(Worked All Europe DX Contest) on September 15. Then on September 17
I ran about 15 EU stations between 1600 and 1700 UTC. I was not on
for several days, but on September 23 I worked about 25 EU stations
on ten meters from 1440-1520 UTC. On September 24 I worked about a
dozen EU's in the hour starting at 1640 UTC. Then on September 25 I
worked about 100 EU stations between 1300-1600 UTC. On September 26
I worked about 125 EU between 1200-1440 UTC. Many Eastern Europeans
and Russians, with occasional Asiatic Russian and Middle-East
stations calling in. Also on September 26, with such good conditions
in the morning, I checked ten meters for JA's before my sunset, and
worked JM7OLW. So, the fall ten meter season is well underway.
Station is a 3 element SteppIR at 50 feet, and about 900 watts out."
 
Great report, Rol. And a little bit of internet searching shows
JM7OLW may have been using his 7 element 10 meter Yagi at 100 feet.
That must help. Check out the evidence and maybe guess which antenna
at http://www.geocities.jp/jm7olw_suke/ . I wouldn't be surprised if
he were using a half-wave dipole on his roof.
 
At the last minute, early Friday, we received this VHF report from
Lawrence, GJ3RAX, in Jersey, one of the Channel Islands. He wrote,
"The VHF bands over here were a bit more interesting this week. A
tropo opening had been predicted due to the high pressure region and
that happened on Monday. I was not able to spend very much time on
the radio but I was on for an hour or so during the early afternoon
and again from 11:30 pm at night. My afternoon QSOs were into
Germany at distances of between 600 and 700 miles. Most were on 2 m
and one on 70 cm. The later QSOs got me into Germany again on 2 m
and 70 cm and also Switzerland on both bands which was about 440
miles. I tried with some of them on 23 cm but nothing was heard this
time."
 
"One of my friends in Guernsey said that he had a large pileup on 23
cm with quite a lot of countries worked. He has a tower with much
higher gain antennas than my log periodic and a better take-off to
the east where I am looking at the local school building which is
about 100 yards away."
 
"One of the members of the VHF and UHF group said that he was too
far north, being in Scotland, to be able to take advantage of that
opening which seemed to be mostly at my latitude."
 
"On Tuesday I was not hearing anything on those bands. During the
evening there was an RSGB contest on 6 m which ran from 8 pm to
10:30 pm BST. Normally I would be lucky to get a couple of QSOs but,
after starting late at 9 pm, I had 17 QSOs. Most were to England
with one GW, one GJ and two in GU. The best distance was 299 miles
which is normally not a good distance for me on 6 m. Typical 6 m
QSOs are much closer or much more distant during the Sporadic E
season but that is now over."
 
"I am anticipating more and better tropo openings during the next
month as I used to find them best during October each year. Last
year when I had just got back on those bands in November I caught
one opening when I worked into Germany on 2 m, 70 cm and 23 cm."
 
This weekend is the CQ World Wide RTTY DX Contest. They have a nice
countdown clock along with rules at http://www.cqwwrtty.com/. As I
write this early Friday morning, the clock shows the contest starts
in 16 hours.
 
For more information concerning radio propagation, see the ARRL
Technical Information Service 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 http://k9la.us/.
 
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 September 19 through 25 were 85, 85, 79, 98, 65,
56, and 61, with a mean of 75.6. 10.7 cm flux was 107.9, 108.8,
110.3, 111.2, 107.8, 110.2, and 111.1, with a mean of 109.6.
Estimated planetary A indices were 11, 6, 7, 5, 5, 9, and 4, with a
mean of 6.7. Estimated mid-latitude A indices were 14, 5, 8, 6, 4,
9, and 4, with a mean of 7.1.
NNNN
/EX