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The K7RA Solar Update


Heightened sunspot activity over the past week no doubt produced the
great conditions during last weekend's ARRL 10 Meter contest.

Compared to the previous seven days, average daily sunspot numbers
jumped from 85 to 136.9, while solar flux averages increased from
137.5 to 150.

Geomagnetic indicators were lower, with planetary A index decreasing
from 14.4 to 7.7, and middle latitude A index from 9.1 to 6.

Higher sunspot numbers and lower geomagnetic indicators is an ideal
combination for favorable HF propagation.

New sunspots appeared every day except December 12, with one new
sunspot on December 8, another on December 9, and three more on
December 10, another on December 13 and one more on December 14.

N0JK commented on the ARRL 10 Meter contest:

"What a difference a year makes. 10 was wide open this year for the
ARRL 10M contest with strong single hop F2 from Kansas to both
coasts. Europe and Japan in, and I completed WAC (Worked All
Continents). Operated fixed mobile with 1/4 wave whip. Solar flux
this year was 148, last year only 78."

The latest prediction from the USAF via NOAA shows solar flux at
164, 162, 160, 158, 154, 152 and 150 on December 16-22, then 120 on
December 23-28, then 125, 130 and 135 on December 29-31, 145 on
January 1-8, 2023, then 140, 130, 125 and 120 on January 9-12, and
115 on January 13-18, then 120 on January 19-24.

Predicted planetary A index is 5 on December 16-17, 10 on December
18, 8 on December 19-20, then 12, 8, and 15 on December 21-23, 20 on
December 24-28, then 12, 10, 12, 8, 5 and 18 on December 29 through
January 3, 2023, 10 on January 4-5, 8 on January 6, 5 on January
7-14, 10 on January 15-16, then 5, 20, 15 and 12 on January 17-20,
and 20 on January 21-24.

F.K. Janda, OK1HH wrote:

"Evolving solar activity was erratic over the last seven days,
starting with the Earth entering a high-speed solar wind stream (up
to 600 km/s) on 8 December.

"It came from a canyon-shaped coronal hole that approached the
western limb of the solar disk. The day after, a magnetic filament
erupted in the Sun's southern hemisphere, but the CME was weak.

"We expected a slight increase in solar wind speed around December
12. However, not only did this not occur, but the solar wind slowed
to 350 km/s in the following days. At the same time, the Earth's
magnetic field calmed down.

"On 12 December, nine groups of sunspots were observed on the Sun,
the largest number so far in the 25th Solar Cycle. Two days later
there were eleven sunspot groups.

"Of these, two regions (AR 3163 and 3165, both with the Beta-Gamma
magnetic configuration) had moderately strong flares (the strongest
on 14 December at 1442 UT was M6 class, produced the Dellinger
effect up to a frequency of 15 MHz). The ejected CMEs have missed
the Earth for now, and we can expect a possible hit from AR3163. The
increase in solar radiation caused an increase in MUF and therefore
the shortest shortwave bands opened up regularly.

"Decrease in solar activity, increasing geomagnetic activity and
worsening of short wave disturbances can be expected after December

The Dellinger Effect is an SID, or "Sudden Ionospheric Disturbance."

David Moore shares this about our Sun's middle corona:

Nine new sunspots. I do not agree that they are dangerous:

Interesting speculation. What happens to cryptocurrency during a
Carrington event?

Newsweek reports on the terminator event:

More and more news about flares:

Another Solar Cycle 19?

N0JK reports:

"Some sporadic-E to W1 from Kansas December 15. Logged K1SIX FN43."

More 6 meter news from KM0T:

"Well, it took since 1999, but I finally worked my first ZL. In
fact, 8 of them. Opening lasted on and off here for about an hour.
Started hearing them just after 0000 UTC. EN40s were working them
first for about 10 minutes before, which tipped me off. I Then
worked AA7A in Arizona at +25, so there was a link perhaps to TEP F2

"There was one station calling an FO, but never saw any report of
the monitoring FO station showing up on PSK reporter. FO was on the
exact path to ZL, but I don't think there was a hop there, perhaps a
blind caller to FO. If anyone actually heard them or worked them,
let us know as that would be an interesting path.

"My antennas were as low to the ground as they could be due to the
ice storm.  Bottom antenna about 25 feet.  (Stacked 6el over 6el,
20' apart.)

"Now that I think about it, flux was 151 and SSN 148.

"I'm pretty sure it was E-skip link, just like when I worked Chatham
Island here some months ago.

"The SW had all kinds of storms (as the whole USA did).  I heard snow
and rain and 'thunder snow' in Arizona.

"That would make sense of such a strong E-skip link to the SW. With
the flux only at 151, seems to me this is a good number for TEP if
you're in the right spot, but not enough to make it to the upper
Midwest with true F2.

"I was lucky that our area had ice only in the morning.  It rained
pretty much all day with bouts of ice, but by the time evening came
around, my ice was off the antennas.

"Signals were strong actually. I gave -01 to -17 reports on the ZLs.
+25 and just below given to stateside 7-land stations I worked in
between the ZLs.

"First ZL was at 0003 - ZL3NW with -11 sig - I got a -07 report.
Strongest ZL was at 0033 - ZL3JT with a -01 sig.  He gave me a +00.

"Last ZL was ZL1AKW, where the spotlight moved a bit north.  At 0107
UTC - he had -06 sig and I got a -19 report."

He did not mention a mode but judging from the signal reports it was
probably FT8 or FT4.

W2ZDP reported on December 14:

"There was a great 6 meter opening yesterday. I first noticed it
around 2020Z and worked 12 stations in grid 'EM,' all on FT8.

"I also noticed that a few of them were working ZLs although I
didn't see the response. After the local 2 meter net at 7 PM local
time, I again worked a few stations in 'EM' when I started seeing
both sides of ZLs working stateside stations. After several
attempts, I finally worked ZL1RS at 0100Z from FM04. Not too bad for
100 watts and a 4 element beam at 30 feet!"

Dr. Tamitha Skov, WX6SWW, the Space Weather Woman, has an
informative new video:

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 for December 8 through 14, 2022 were 115, 116, 111,
141, 142, 159, and 174, with a mean of 136.9. 10.7 cm flux was 143,
149.1, 141.7, 147,7, 150.8, 153, and 164.7, with a mean of 150.
Estimated planetary A indices were 11, 11, 8, 10, 6, 4, and 4, with
a mean of 7.7. Middle latitude A index was 9, 9, 6, 7, 5, 3, and 3,
with a mean of 6.




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