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29 September, 2007
Last week's report stated the possibility that zero-sunspot days were
about to end, but no such luck. Instead we've seen no sunspots for three
weeks straight, since September 7.
The September 20 forecast from NOAA and the US Air Force showed solar
flux values rising to 70 on September 21. (See
http://sec.noaa.gov/ftpdir/forecasts/45DF/092045DF.txt).
The next day's prediction reverted to 67
(http://sec.noaa.gov/ftpdir/forecasts/45DF/092145DF.txt).
The September 21 prediction had solar flux rising to 70 again, but not
until September 29 to October 1, then falling back below 70, then back
to 70 again for October 18-28.
Now the September 27 forecast has solar flux staying around 67-68 through
November 11. You can see all the latest daily forecasts for solar flux
and planetary A index at
http://sec.noaa.gov/ftpmenu/forecasts/45DF.html.
The possible end to the stretch of zero sunspot days was based on the
observation that when the solar flux is 70 or higher, there is at least
one visible sunspot. This makes it seem that we are still at the bottom
of the cycle, or haven't quite reached it.
Those daily forecasts are posted after 2100z. There is a new
sunspot 970 emerging, so perhaps the September 28 forecast will show solar
flux back to 70 or higher. There is currently a solar wind hitting earth,
and currently the interplanetary magnetic field points south, which leaves
earth vulnerable. That same forecast on September 27 predicts a planetary
A index for September 28 to October 3 at 15, 25, 12, 8, 8 and 15, so we
may see unsettled to
active geomagnetic conditions on Saturday, September 29 and again Wednesday,
October 3. Already early Friday morning UTC (which is late Thursday on
the West Coast) we've seen the planetary K index as high as 6. Lately
with quiet conditions the K index has been 1 or 2. Above 3 is considered
unsettled or active geomagnetic
conditions.
Geophysical Institute Prague predicts unsettled conditions for September
28, unsettled to active September 29, unsettled September 30, quiet October
1, unsettled October 2-3, and quiet to unsettled October 4.
Jeff Lackey, K8CQ of Saint Simons Island, Georgia wrote in with an interesting
observation. He created a graph (which unfortunately is not on the web
for viewing) which plots periods in which the solar flux drops below 80
for extended periods. It shows the longest run at the end of cycle 22
was from January 8 through July 7, 1996, 182 days. The second longest
run from 11 years ago was 112 days from August 2 to November 21, 1996.
The latest and also the longest run
at the end of the current cycle 23 began on June 9, 2007 and so far runs
112 days through September 28. The September 28 morning reading at Penticton
(the noon reading is the official value) has a very low solar flux value
of 64.4.
The latest forecast from the Air Force shows solar flux below 80 for
the next 45 days, so if this turns out to be true, that would put this
run up toward the longest one from 11 years ago. We are today already
equal to the second longest run of cycle 22, and are in the longest run
of the current cycle. The second longest run for the current cycle is
77 days, ending after April 25, 2007.
Note there is nothing magic about a solar flux value of 80, but Jeff
is a numbers guy and found this to be an interesting threshold for his
analysis of solar minima.
Despite the lack of sunspots, hams are still communicating around the
world, and reports of working 3B7C with modest stations are still coming
in. WA2VQW worked them on 30 meters from his car at 2115z on September
18 while sitting at a traffic light in Hawthorne, New York. Mike was on
his way to higher ground, but never made it, instead working the DXpedition
while stuck in traffic. W4WNT of Oak Island, North Carolina reports a
30 meter 3B7C contact at 0212z on
September 22 using an 80-20 meter fan dipole bent around his deck at 30
feet.
On September 18, Ken Tata, K1KT of Warwick, Rhode Island noticed an online
propagation map tracking 2 meter APRS stations showed a path from Rhode
Island to Newfoundland's Avalon Peninsula. Ken was running 50 watts into
a dipole, a driven element removed from an 11 element Yagi and mounted
on a pole. He reports, ''I worked VE1PZ, in FN85, 100 mi north of Halifax;
VE1HD, FN95, 100 mi east of Halifax; and VE1AHM, FN76, near Moncton, New
Brunswick''.
He reported that many of the better equipped stations in Southern New
England were working into the Maritime Provinces on 432 and 1296 MHz.
Ken didn't say what mode he used. Ken sent along web-based VHF propagation
sites he likes for checking real-time conditions:
http://www.mountainlake.k12.mn.us/ham/aprs/,
http://www.dxinfocentre.com/tropo.html,
http://www.vhfdx.net/spots/map.php,
and
http://dxworld.com/144prop.html.
This weekend is the Texas QSO Party (see http://txqp.net),
and if I were in California, to work Texas I would try 15 meters 1900-2230z,
20 meters 1500-0230z, 40 meters any time, but best bet probably 0200-1200z,
and 80 meters 0230-1230z.
From Atlanta to Texas try 20 meters 1830-2030z, 40 meters best 2230-0230z,
80 meters 2200-1330z.
From Seattle, 15 meters 1930-2230z, 20 meters 2100-0300z, 40 meters best
0130-1230z and weakest 1630-2100z, 80 meters 0300-1300z.
From California, 15 meters 1900-2230z, 20 meters 1500-0230z, 40 meters
best 0130-1230z and weakest 1700-2130z. 80 meters best 0300-1200z.
From New York, 20 meters 1500-0030z, 40 meters best 2330-1130z and weakest
1530-2000z, 80 meters 0130-1030z.
From Ohio, 20 meters 1500-2300z, 40 meters almost around the clock, but
0630-1030z may be questionable, and best signals 2200-0400z and 1130-1400z.
80 meters 2230-1300z, with strongest signals 0030-0200z and around 1130z,
weakest signals 1600-1930z.
All of these are best guesses worked out with W6ELprop. Look for details
on using this tool in back issues of this bulletin.
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 September 20 through 26 were 0, 0, 0, 0, 0, 0 and
0 with a mean of 0. 10.7 cm flux was 66.8, 66.9, 66.7, 66.3, 66.1, 66.2,
and 66.5 with a mean of 66.5.
Estimated planetary A indices were 10, 9, 11, 15, 10, 6 and 3 with a
mean of 9.1. Estimated mid-latitude A indices were 6, 7, 10, 11, 7, 5
and 2, with a mean of 6.9.
Source: The
American Radio Relay League
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reports can be found at:
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