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ARRL Propagation Bulletin ARLP005 (2023)

ARLP005 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 5  ARLP005
From Tad Cook, K7RA
Seattle, WA  February 3, 2023
To all radio amateurs 

ARLP005 Propagation de K7RA

Solar activity softened again this week, with average daily sunspot
numbers changing from 162 to 80.7, and solar flux from 198.9 to

This is quite a dramatic shift from the excitement of a couple of
weeks ago. To review, average weekly sunspot numbers from the first
Propagation Forecast bulletin of 2023 went from 97 to 135.9, 173.4
and 162. Average weekly solar flux from 157.8 to 181.2, 221.8 and

This variability is expected. Soon, perhaps in the next solar
rotation, activity will rise again. The graphs we see of smoothed
sunspot numbers are smooth because the numbers are averaged over a
whole year.

Geomagnetic numbers barely changed at all, with planetary A index
shifting only from 8.1 to 7.9 and the middle latitude numbers did
not change at all, 5.9 last week and 5.9 this week.

Predicted solar flux is 135 on February 3, 140 on February 4-5, 145
on February 6, 150 on February 7-9, 155 on February 10-13, 150 on
February 14-16, 145 on February 17, 140 on February 18-19, 135 on
February 20, 130 on February 21-23, 125 on February 24-25, 140 on
February 26-27, 135 on February 28 through March 4, then 140 and 145
on March 5-6, 150 on March 7-8. and 155 on March 9-12.

Predicted planetary A index is 8, 5 and 5 on February 3-5, 10 on
February 6-7, 8 on February 8-9, then 12, 5, 8 and 8 on February
10-13, 5 on February 14-17, then 8, 7, 5 and 5 on February 18-21, 10
on February 22-24, 5 on February 25-27, then 15, 10 and 8 on
February 28 to March 2, and 5 on March 3-5, then 15 on March 6-8,
then 12, 8 and 7 on March 9-11 and 5 on March 12-16.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere February 3-9, 2023 from F.K. Janda, OK1HH:

"January this year was another surprise in the development of Solar
Cycle 25, although we are still about two years away from its peak.
Sunspots have grown larger, while the configuration of the magnetic
fields that make them up has become increasingly complex, leading to
an increase in the number and intensity of eruptions, so far only
moderately powerful.

"Solar flux between 12 and 21 January was above 200, while the solar
wind increased.

"In the last week, after the large sunspot groups AR3190 and AR3192
fell behind the western limb of the solar disk, solar activity
decreased. Between January 27-29 and February 1, solar wind
intensified, apparently still blowing from the active regions that
had already set.

"Further, we expect an irregular evolution without major
fluctuations. Helioseismological observations show that the activity
of AR3190 and AR3192 continue on the Sun's far side. We'll have to
wait another week for their reappearance on the eastern limb."

Mike Schaffer, KA3JAW in Easton, Pennsylvania reports again on his
10 meter FM activity. He notes the daily solar flux dropped about
100 points from mid-January, but good 10 meter propagation

Daily from 1300-1600 UTC he has good propagation to Europe, and is
recently hearing Israel on 10 meter FM, about 5,700 miles away via
F2 propagation.

Mike notes, "Remember, 29.6 MHz is the national FM calling
frequency, after making the initial contact you should QSY to a
lower frequency, such as 29.5 or 29.49 MHz, to continue the QSO."

Jim Hadlock, posting to the email list for the Western Washington DX
Club noted that sunspot numbers recently hit a 9-year high.

Jim posted this from

Scott Avery, WA6LIE wrote:

"Today was a fluke on 10 meters FT8.  I worked LA7HJA on FT8 on
Thursday February 2nd at 0041 UTC.  He gave me a +04 and I gave him
a -13 dB report.  Great reports and tried calling one other LA, but
no luck. I confirmed the QSO with his ClubLog.

"For the past month or so, European openings are from about
1500-1730 UTC here in California.

"Have no clue to the method of propagation on this late afternoon's

"I was just using a wire Delta Loop at 30' feedpoint, part of my
inverted Vees all common feedpoint.

"You know in this hobby you just got to be in the right place at the
right time!"

Toivo Mykkanen, W8TJM in Liberty Lake, Washington wrote:

"Just had the best Aurora Path into Scandinavia since we last spoke
last year. Today, 1 Feb, I was able to work 4 stations on SSB in
Finland from Eastern Washington and all of them were 10-15 dB over
S9 with a slight bit of flutter. It was 10 PM in Finland, well after
15 meters usually shuts down there.   Was great to connect with my
heritage as my parents are from Finland. The Finnish stations were
working stations all across the USA and Canada."

Bil Paul, KD8JUI, recalling television reception at the peak of
Solar Cycle 19, wrote:

"We were in Wisconsin, around '58 or '59, and we could usually only
pick up with good reception two TV stations. One Sunday morning I
got up and switched on the TV. I started getting good reception from
the SE U.S., Georgia and Florida.

"As time went on, the skip gradually changed to receiving Alabama
and Mississippi, and finally ended with Texas. I'm not sure what
frequencies were being used for those channels (2 through 13) back

Send your tips, reports, observations, questions and comments to

For more information concerning shortwave radio propagation, see and the ARRL Technical Information
Service at . For an
explanation of numbers used in this bulletin, see .

An archive of past propagation bulletins is at . More good
information and tutorials on propagation are at .

Instructions for starting or ending email distribution of ARRL
bulletins are at .

Sunspot numbers January 26 through February 1, 2023 were 104, 84,
76, 80, 67, 65, and 89, with a mean of 80.7. 10.7 cm flux was 150.6,
144.9, 137.6, 137, 135.9, 137, and 133.5, with a mean of 139.5.
Estimated planetary A indices were 11, 9, 10, 5, 5, 9, and 6, with a
mean of 7.9. Middle latitude A index was 9, 6, 8, 5, 4, 6, and 3,
with a mean of 5.9.


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