ARRL

ARRL Propagation Bulletin ARLP051 (2005)

SB PROP @ ARL $ARLP051
ARLP051 Propagation de K7RA

ZCZC AP51
QST de W1AW  
Propagation Forecast Bulletin 51  ARLP051
From Tad Cook, K7RA
Seattle, WA  December 2, 2005
To all radio amateurs 

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

Daily sunspot and solar flux averages over the past week were down,
and the geomagnetic indices were up. Average daily sunspot numbers
were down nearly 15 points to 33.7, and average daily solar flux
declined nearly 13 points to 84.2.

Currently sunspot and solar flux numbers are rising due to sunspot
826, which is growing rapidly and moving toward the center of the
solar disk, giving it maximum influence here on Earth. It also
could be a source of flares, which would not be good for the ARRL
160 Meter CW Contest this weekend. Predicted solar flux for today
(Friday) through Monday December 5 is 100, 105, 105 and 105.
The predicted planetary A index for the same days is 15, 12, 8 and 5,
although those numbers will be higher if sunspot 826 becomes
especially active.

Back in Propagation Forecast Bulletin ARLP048 (see
http://www.arrl.org/w1aw/prop/2005-arlp048.html) there was a report
of WB5AGZ in Stillwater, Oklahoma picking up a 10 meter repeater
from New York (KQ2H) during the middle of the night and into early
morning. We now have another similar report, also from Oklahoma.
Stan Stephens, WA6SKD of Midwest City, Oklahoma wrote in with this
narrative:

"I would like to confirm Martin McCormick's (WB5AGZ) observations
from Stillwater, Oklahoma on late night 10 meter FM signals from
KQ2H on 29.620 MHZ. I am in Midwest City, Oklahoma (near OKC). I
monitor the 10 meter FM band always looking for a contact or two,
since I am a night owl. I have observed KQ2H many times after
midnight, almost too numerous to keep track. These openings have not
just been this month, but also spring and summer. What I hear does
sound like a link with stations having no idea they are being copied
59+ in Oklahoma."

He continues, "Now for the good part, these late night signals are
not limited to KQ2H. I have also noted signals from the southern
U.S. and Midwest with an occasional California 10 FM repeater. Also,
like Martin, I notice no other signals on 10M, and 12M, 15M, and 17M
also with no signals. Trying to raise these repeaters can be
difficult on my Azden PCS 2800 (10 watts and Ringo), but when I do
get a response from the machine no one is home!"

Stan goes on to say, "In general I find the 10 meter FM band is open
a lot more than it is given credit for, I am not sure what
conditions allow this but no complaints on this end. It is cool
making a 10 meter FM contact with a distant station at 0300 in the
morning. I have been on 10M FM with my Azden for 23 years, my log
books really show varied conditions on 10M FM. Although some years
have been better than others, this includes sunspot cycle minimums."

This is very interesting, and shows us that 10 meters may be open
more often than we think, even in the middle of the night when there
shouldn't be any conventional propagation. Remember that the ARRL
10 Meter Contest is coming up next weekend, December 9-11.

November ended on Wednesday, so let's look at the monthly averages
for solar flux and sunspot numbers.

The average daily sunspot numbers for the months September 2004
through November 2005 were 50, 77.9, 70.5, 34.7, 52, 45.4, 41, 41.5,
65.4, 59.8, 68.7, 65.6, 39.2, 13 and 32.2. Average daily solar flux
for the same months was 103, 106, 113.7, 95, 102.3, 97.2, 89.9,
85.9, 99.5, 93.7, 96.5, 92.4, 91.9, 76.6 and 86.3.

It looks like activity bounced back a bit in November, but look for
the general trend to be down until the sunspot minimum, which should
be about a year from now, or maybe a little longer.

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 and an explanation
of the numbers used in this bulletin see the ARRL Technical
Information Service propagation page at,
http://www.arrl.org/tis/info/propagation.html. An archive of past
bulletins is found at, http://www.arrl.org/w1aw/prop/.

Sunspot numbers for November 24 through 30 were 30, 39, 30, 26, 27,
27 and 57 with a mean of 33.7. 10.7 cm flux was 86.6, 79.9, 80.8,
80.7, 81.9, 84.7, and 94.7, with a mean of 84.2. Estimated planetary
A indices were 9, 10, 5, 2, 9, 5 and 10 with a mean of 7.1.
Estimated mid-latitude A indices were 6, 8, 3, 2, 6, 6 and 9, with a
mean of 5.7.
NNNN
/EX