The K7RA Solar Update

SEATTLE, WA, Aug 5, 2005--Average daily sunspot numbers rose
by more than 68 points this week to 83.7 compared to last week's
numbers. This is four weeks after the recent large number of
sunspots around the beginning of July, which corresponds to the
rotation of the sun relative to Earth. That area of the sun is now
back in view, but with sunspots diminished.

The reporting week began July 28 with heightened geomagnetic
activity, but it quieted down. Prediction for the next few days is for
solar flux to remain above 100, which is expected until August 10.
Current geomagnetic conditions are slightly unsettled, but after
August 10 are predicted to be quiet. Barring an unexpected solar
flare, expect good conditions--at least relative to recent HF
propagation at this lower spot on the solar cycle. The Northern
Hemisphere is about halfway between the longest day of the year
and the fall equinox, and fall is typically favorable for HF
propagation.

Looking at the monthly averages, we see a tremendous variation
from month to month, with a rise in average sunspot and solar flux
numbers for July. This was due to the unusually large number of
sunspots early in the month.

The average daily sunspot numbers for the months October 2004
through July 2005 were 77.9, 70.5, 34.7, 52, 45.4, 41, 41.5, 65.4,
59.8 and 68.7. Average daily solar flux for the same months was
106, 113.7, 95, 102.3, 97.2, 89.9, 85.9, 99.5, 93.7 and 96.5.
Looked at in isolation, the numbers since early 2005 almost
suggest a rising solar cycle.

The overall trend for the remainder of this sunspot cycle will be
down, and it becomes more obvious when we average the
numbers over a long period. Currently we are looking to reach
solar minimum around the end of 2006. We've been reporting this
for some time now, and this is based on the table of predicted
smoothed sunspot numbers that appears occasionally in the back of the weekly
Preliminary
Report and Forecast from the NOAA Space Environment Center. This week's copy, No
1561,
contains that table. Looking back over the past few years shows the predicted
values out to the
end of 2007, just as it does today.

Look at this table for predicted smoothed sunspot numbers from four years ago,
in August 2001,
and compare it to the table in the latest issue noted above.

Even back in 2001 the predicted low numbers for the end of next year were the
same as today's
prediction. What changed are the predicted numbers for a few months from now,
which are
higher than predicted four years ago and, of course, the actual smoothed numbers
for all that
time in between differ also.

We must go back to 2000 to find tables that end earlier than 2007. Here is one
from August
2000 that ends in 2005.

Until I rechecked this, I thought the table was perhaps updated yearly, with
another year in the
future added on. I've asked the NOAA Space Environment Center to clarify this as
well as the
July 18 report of a sunspot number of -1 mentioned recently.

Vic Woodling, WB4SLM, wrote about recent VHF DX, but on the FM broadcast band,
about half
way between our own 6 and 2-meter bands. Vic's girlfriend lives near Haysville,
North Carolina,
in grid square EM85, and around noon local time on Tuesday, August 2, she heard
KRKX in
Billings, Montana, on 94.1 MHz on her car radio. The strong signal was
full-quieting, and the
KRXK transmitter site is in grid square DN55, a little less than 1500 miles
away.

For more information concerning radio 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 July 28 through August 3 were 29, 69, 62, 110, 102, 112 and
102 with a
mean of 83.7. 10.7 cm flux was 95.8, 103.7, 105, 109.7, 111.2, 110.2 and 108.9,
with a mean of
106.4. Estimated planetary A indices were 28, 19, 16, 9, 16, 12 and 11 with a
mean of 15.9.
Estimated mid-latitude A indices were 18, 14, 11, 10, 18, 9 and 6, with a mean
of 12.3.
(K7RA, ARRL)

dxAce
Michigan
USA

http://www.iserv.net/~n8kdv/dxpage.htm