The K7RA Solar Update

SEATTLE, WA, May 5, 2006--This was a nice, quiet week with no
notable geomagnetic activity. In fact, the middle latitude K index
was zero for a 36-hour period centered on April 30. At
approximately the same time the high latitude college K index was
zero for 51 hours straight. Average daily sunspot numbers were
nearly double those of the previous seven days, rising by more
than 29 points to 59.7.

As this update was being written early today, the IMF was pointing
south, leaving Earth vulnerable to solar wind. The planetary A
index reached five on Thursday, May 4, and it's predicted to hit 20,
30, 20 and 12 for May 5-8. Geophysical Institute Prague gives a
forecast until May 11 of active geomagnetic conditions on May 5
and 6, unsettled May 7, quiet to unsettled May 8, quiet on May 9,
back to unsettled on May 10, and unsettled to active on May 11.

The average daily sunspot numbers for the months April 2005
through April 2006 were 41.5, 65.4, 59.8, 68.7, 65.6, 39.2, 13, 32.2,
62.6, 26.7, 5.3, 21.3 and 55.2. Average daily solar flux for the same
months was 85.9, 99.5, 93.7, 96.5, 92.4, 91.9, 76.6, 86.3, 90.8,
83.4, 76.5, 75.5 and 88.9.

Paul Peters, VE7BZ, of Cobble Hill, British Columbia, says
conditions around three quiet days last week were fantastic. "On
April 29, 30 and May 1, the 20 meter band conditions to Europe
were almost unbelievable they were so good," he wrote. "On April
29 and 30, I called CQ once at 0300z and four hours later at 0700z
I was still working down an endless pileup. Normally for us -- living
this far north, 20m phone is usually dead in our evenings, but such
was not the case recently. These were great nights!"

Richard Vincent, KR7R/HS0ZFQ, retired from the US Postal Service in Seattle and
now lives in
Chiang Rai in extreme northern Thailand, between the borders with Laos and
Myanmar
(Burma). About those same days, he writes: "I was hearing stateside signals all
over the place
on 20 meter SSB starting about 1300z, which is 8:00 PM local time. From this end
VR2XMT,
Charlie Ho in Hong Kong was running USA stations and so were a couple of the
Russian big
guns. I had not heard conditions like that since I got on the air here last
October". Richard
currently uses a dipole, and has plans to soon put up a quad.

Last week's bulletin mentioned Greg Andracke, W2BEE, of Pine Plains in upstate
New York and
his experience working Chagos on 30 meters early on a Saturday morning in
mid-April. Several
people wrote in to say that this was a normal time to work Chagos via the long
path on that
band. Actually, that is true for many other places in North America, but not
where Greg is, in the
Northeast. The people we heard from were all south and west of Greg, although
checking a
propagation prediction program shows that the Southeast United States should
have a good
path as well. Southern California around that time on that date would have a
very good short
path opening to Chagos.

Dale Tongue, AC7NP, wrote from El Paso, Texas, to ask about where to find
sunspot graphs on
the Web. The WM7D Web site has a graph of the last year of sunspots as well as
all recorded
sunspot cycles back to 1749. The NOAA Space Environment Center has a graph of
the current
sunspot cycle is at http://dawn.sec.noaa.gov/SolarCycle/, while the DX
Listeners' Club site
compares recent cycles and offers a graph of the past few months too. Links
lower on the page
provide some interesting historical data.

And finally, Thomas Giella, KN4LF, of Lakeland, Florida, has started a new
e-mail listserver for
radio propagation. Subscription information is on Yahoo.

For more information concerning propagation and an explanation of the numbers
used in this
bulletin see the ARRL Technical Information Service Propagation page. An archive
of past
bulletins is on the ARRL Web site.

Sunspot numbers for April 27 through May 3 were 63, 68, 64, 62, 51, 58 and 52,
with a mean of
59.7. The 10.7 cm flux was 100.7, 100.1, 101.2, 99.9, 93.4, 89.4, and 89, with a
mean of 96.2.
Estimated planetary A indices were 5, 12, 3, 1, 2, 4 and 3, with a mean of 4.3.
Estimated
mid-latitude A indices were 3, 10, 2, 0, 2, 4 and 2, with a mean of 3.3.
(K7RA, ARRL)

dxAce
Michigan
USA