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29 December, 2007
ARLP054
Last week this bulletin reported sunspot 978 rotating from view. Now
through a process called helioseismic holography, an image of the Sun's
far side shows the spot fading away. 978 was first visible December 6,
and squarely faced earth on December 12. Perhaps January 2 or 3 we will
again see 978 peeking around the eastern limb, if it hasn't by then faded
completely.
No sunspots at all this week, and average daily solar flux was down over
12 points from the previous week. Geomagnetic activity was still low,
and down slightly. Over the next week the planetary A index is predicted
to be 5 on each day, a low number indicating a stable and quiet geomagnetic
field. Solar flux is expected to stay around 72 for Dec 28-30, rising
to 73 on December 31, 75 for the first few days of the new year, then
up to 80 and 85 by January 4-5. This indicates an expectation for the
return of sunspot 978 or possibly other sunspots around the same time.
Geophysical Institute Prague predicts quiet geomagnetic conditions December
28-30, quiet to unsettled December 31, and quiet January 1-3.
Michael Mark, VE4MM was portable /6Y5 December 10-19 from Runaway Bay,
Jamaica when he went to visit a new home built by a friend from Winnipeg.
Michael brought a 2-element beam, and occupied the top floor with an ocean
view. He worked all the five bands from 10 to 20 meters, concentrating
on 17 meters. This was during the recent
robust sunspot activity, and it was a real treat experiencing HF conditions
from 18.46 degrees North Latitude, far different from his home at 49.84
degrees. He commented, "I made my own conditions on 10 and 12 meters
just by calling CQ." I think he means that when first tuning the
band, it sounded dead, but came to life once VE4MM/6Y5 was heard. All
together he made almost 1400 contacts, most of them on 17 meters.
We received more reports of 10 meter surprises, probably due to sporadic-E,
although it doesn't seem the season for it. Hank Pfizenmayer, K7HP of
Phoenix, Arizona heard "horrible 40-meter noise wiping out FJ/OH2AM,"
so he switched to 10 meters to see if he could pinpoint the source with
his beam. This was well after dark, and more than six hours after local
sunset at 0632-0636z. He heard beacons from Kansas, Oklahoma and Missouri.
W0ERE/B in Southwest Missouri was S9 from 5 watts into a vertical.
This weekend is the Stew Perry Topband DX Challenge, an annual 160 meter
CW operating event. The link,
http://www.jzap.com/k7rat/stew.html
given in the ARRL Contest Calendar doesn't seem to work early Friday morning,
although it may be back by the time you read this. With no sunspots in
sight, and quiet geomagnetic conditions, a long Winter's night is a great
time for 160 meters.
Try http://www.arrl.org/contests/months/dec.html
for rules, or check out http://tinyurl.com/3dsltv
and
http://www.radio-sport.net/stew07_preview.htm
for more details.
Don't forget Straight Key Night on New Year's Eve. This runs from 0000-2359z
January 1, and is lots of fun, and a nice excuse to activate some old
and classic manual keys. See,
http://www.arrl.org/contests/rules/2008/skn.html
for details.
Next week in the first bulletin of the New Year we will review some of
the numbers, including average sunspot numbers for the whole of 2007.
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 at,
http://www.arrl.org/tis/info/propagation.html.
For a detailed explanation of the numbers used in this bulletin see,
http://www.arrl.org/tis/info/k9la-prop.html.
An archive of past propagation bulletins is at http://www.arrl.org/w1aw/prop/.
Monthly propagation charts between four USA regions and twelve overseas
locations are at, http://www.arrl.org/qst/propcharts/.
Sunspot numbers for December 20 through 26 were 0, 0, 0, 0, 0, 0 and
0 with a mean of 0. 10.7 cm flux was 72.6, 71, 71.5, 71.4, 71.4, 72, and
72.6 with a mean of 71.8. Estimated planetary A indices were 12, 11, 7,
6, 2, 2 and 2 with a mean of 6. Estimated mid-latitude A indices were
10, 9, 7, 4, 1, 2 and 1, with a mean of 4.9.
Source: The
American Radio Relay League
•
DX Spots popup
• All propagation
reports can be found at:
http://www.southgatearc.org/propagation
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