12/20/2024

Excellent HF conditions greeted hams in the ARRL 10-Meter contest
last weekend. Recent indicators show a sudden shift to two digit
daily sunspot numbers from three, and although there is nothing
significant about 100, it makes one notice.

All daily sunspot numbers this week were 97 or less.

Perhaps this indicates a move off of solar maximum, or to a future
with a second maximum.

Solar activity was way, way down this week with an average daily
sunspot number at just 88.

Predicted solar flux is 175, 180, 180, 185 and 180 on December
20-24, 175 on December 25-26, 180 on December 27, 185 on December
28-29, 180 on December 30 through January 2, 2025, and 175 on
January 3-4, 170 on January 5-6, 160 on January 7-8, then 165, 179,
165, and 170 on January 9-12, 165 on January 13-14, 170 on January
15-16, 175 on January 17-18, 180 on January 19-23, and 185 on
January 24-25.

The forecast for Planetary A index shows a quiet 5 on December
20-22, 8 on December 23-24, and 5 on December 25 through January 4,
2025, then 15 and 8 on January 5-6, 5 on January 7-9, then 12, 10
and 8 on January 10-12, and 5 on January 13-31.

OK1HH does not seem to have a commentary this week.

The latest report from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/wClI7PKn3K0[1]

Send your tips, reports, observations, questions, and comments to k7ra@arrl.net[2]. When reporting observations, don't forget to tell us
which mode you were operating.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation[6] . More good
information and tutorials on propagation are at http://k9la.us/[7] .

Also, check this article:

https://bit.ly/3Rc8Njt[8]

"Understanding Solar Indices" from September 2002 QST.

Instructions for starting or ending email subscriptions to ARRL
bulletins are at http://arrl.org/bulletins[9] .

Sunspot numbers for December 12 through 18 2024 were 91, 82, 86, 97,
90, 88, and 82 with a mean of 88. 10.7 cm flux was 172, 163.7,
170.5, 172, 166.7, 170, and 173.5 with a mean of 169.8. Estimated
planetary A indices were 6, 4, 10, 12, 14, 29, and 15, with a mean
of 12.9. Middle latitude A Index was 4, 2, 8, 9, 11, 20, and 12,
with a mean of 9.4.

ÿ


[1] https://youtu.be/wClI7PKn3K0
[2] mailto:k7ra@arrl.net
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://arrl.org/w1aw-bulletins-archive-propagation
[7] http://k9la.us/
[8] https://bit.ly/3Rc8Njt
[9] http://arrl.org/bulletins

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þ Synchronet þ Whiskey Lover's Amateur Radio BBS

12/30/2024

Strong solar activity continues, with worldwide propagation on 10
and 12 meters quite commonplace.

Predicted solar flux is 255, 250, 210, 200, and 195 on December 30,
2024 through January 3, 2025, 190 on January 4-5, 170 on January 6,
160 on January 7-8, then 165, 170 and 165 on January 9-11, 170 on
January 12-13, 175 on January 14-15, 180 on January 16, 185 on
January 17-18, 200 on January 19-23, 185 on January 24-26, 175 on
January 27, and 180 on January 28-30, 2025.

Predicted planetary A index is 8, 50, 20 and 8 on December 30, 2024
through January 2, 2025, 5 on January 3-4, 8 on January 5-6, 5 on
January 7-9, then 12, 10 and 8 on January 10-12, 5 on January 13-15,
then 8, 10 and 10 on January 16-18, 8 on January 19-23, and 5 on
January 24-31.

The latest from F. K. Janda, OK1HH:

"A cooling water pipe burst in the server room of the Joint Science
Operations Center (JSOC) at the Solar Dynamics Observatory (SDO) in
California on 26 November 2024. Since then, data from the
Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Array
(AIA) instruments have been unavailable.

"On the popular website https://www.solarham.com/[1] on the bottom
left, we usually find information on activity on the far side of the
Sun (at https://www.solarham.com/farside.htm[2]) that would be needed
to predict developments around the Christmas season, for example.
This is because we were expecting the rise of active regions on the
Sun that were very active during the last solar revolution and whose
high activity we know about thanks to CMEs and the influx of protons
from flares on the Sun's far side.

"As expected, active regions on the Sun did appear and they were not
alone. Moderate solar flares are the order of the day, while we have
been expecting a geomagnetic disturbance during the Christmas
holidays since after the CME registration. But the particle clouds
missed the Earth, the disturbance did not take place, and
ionospheric shortwave propagation conditions remained above average.

"But even better propagation conditions are likely to await us next
year. The high solar activity in October this year was probably not
yet the peak of the 25th cycle - that is yet to come!"

From Space.Com, "The Sun in 2025: How the solar cycle will shape our
year ahead":

https://bit.ly/3DA4N7L[3]

The latest report from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/qPI4_otUAME[4]

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[5] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[6]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[7] .

An archive of past propagation bulletins is at, http://arrl.org/w1aw-bulletins-archive-propagation[8] . More good
information and tutorials on propagation are at, http://k9la.us/[9] .

Also, check this article:

https://bit.ly/3Rc8Njt[10]

"Understanding Solar Indices" from September 2002 QST.

Instructions for starting or ending email subscriptions to ARRL
bulletins are at, http://arrl.org/bulletins[11] .

Sunspot numbers for December 19 through 25, 2024 were 96, 148, 152,
176, 199, 219, and 218 with a mean of 172.6. 10.7 cm flux was 175,
184, 201.2, 223.3, 238.3, 258.5, and 252.7 with a mean of 219.
Planetary A index was 11, 13, 16, 14, 12, 12, and 5 with an average
of 11.9. Middle latitude A Index was 9, 10, 13, 15, 11, 9, and 5,
with a mean of 10.3.

ÿ


[1] https://www.solarham.com/
[2] https://www.solarham.com/farside.htm
[3] https://bit.ly/3DA4N7L
[4] https://youtu.be/qPI4_otUAME
[5] http://www.arrl.org/propagation
[6] http://arrl.org/propagation-of-rf-signals
[7] http://arrl.org/the-sun-the-earth-the-ionosphere
[8] http://arrl.org/w1aw-bulletins-archive-propagation
[9] http://k9la.us/
[10] https://bit.ly/3Rc8Njt
[11] http://arrl.org/bulletins

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

01/03/2025

Currently a geomagnetic storm is raging. On January 1-2, Alaska's
college A index reached 113.

Predicted planetary A index is 12 on January 3, then 18, 18, 12, 10
and 8 on January 4-8, 5 on January 9-10, 10 and 8 on January 11-12,
5 on January 13-15, 12 on January 16, 10 on January 17-20, 5 on
January 21-25, then 8, 50, 20 and 8 January 26-29.

Predicted solar flux is 215 on January 3-4, then 205, 210, 205 and
205 on January 5-8, then 200, 170 and 165 on January 9-11, 170 on
January 12-13, 175 on January 14-15, 180, 190, 200, 210 and 220 on
January 16-20, 230 on January 21-25, 240 on January 26-27, then 220,
200 and 195 on January 28-30.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - January 2, 2025, from OK1HH:

"Considering the high solar flare activity, there was a relatively
high probability of an increase in geomagnetic activity during the
Christmas holidays.

"But currents of enhanced solar wind avoided the Earth and therefore
it was surprisingly quiet for a relatively long period from
Christmas almost until the end of the year, more precisely from 25
to 30 December.

"Strong solar flares in the last two days of December were followed
by CMEs that were at least partially directed towards the Earth.
This prompted all geomagnetic field activity forecasters to jointly
and indiscriminately predict the occurrence of geomagnetic
disturbances and auroras for 31 December and 1 January.

"Particles ejected by the second of the major eruptions hit the
Earth more effectively. Therefore, the geomagnetic disturbance on 31
December was weaker. The major disturbance on January 1, 2025 was
accompanied by beautiful auroras.

"At first approximation, the unexpected development of ionospheric
shortwave propagation on New Year's Day may have seemed surprising.
Not only were they not bad, but their development was irregular,
while the MUF values were even above average. The cause can be found
also in the previous calm development (25 to 30 December) and also
in the fact that the solar wind speed started to increase gradually
only from 1 January.

"The most active regions on the Sun now fall behind the western limb
of the solar disk. Therefore, solar activity will slowly decrease.
But it will be sufficient to open all shortwave bands. At the same
time, the Earth's magnetic field activity will also be decreasing,
so the evolution of ionospheric propagation conditions should be
more stable, while remain mostly above average on most days."

An article from "yourweather.co.uk" regarding the solar max:

https://bit.ly/41ZnwUq[1]

Latest video from Dr. Tamitha Skov, WX6SWW (Space Weather Woman):

https://youtu.be/k3gxVE74Xa0[2]

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] .

An archive of past propagation bulletins is at, http://arrl.org/w1aw-bulletins-archive-propagation[6] . More good
information and tutorials on propagation are at http://k9la.us/[7] .

Also, check this:

https://bit.ly/3Rc8Njt[8]

"Understanding Solar Indices" from September 2002 QST.

Instructions for starting or ending email subscriptions to ARRL
bulletins are at, http://arrl.org/bulletins[9] .

Sunspot numbers for December 26, 2024 through January 1, 2025 were
211, 233, 213, 209, 162, 172, and 163 with a mean of 194.7. 10.7 cm
flux was 255.8, 258.5, 260.3, 254.7, 223.5, 216.2, and 219.2 with a
mean of 241.2. Planetary A index was 3, 3, 4, 5, 7, 10 and 86 with
an average of 16.9. Middle latitude A Index was 3, 5, 7, 10, 7, 10,
and 48, with a mean of 12.9.

ÿ


[1] https://bit.ly/41ZnwUq
[2] https://youtu.be/k3gxVE74Xa0
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://arrl.org/w1aw-bulletins-archive-propagation
[7] http://k9la.us/
[8] https://bit.ly/3Rc8Njt
[9] http://arrl.org/bulletins

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

01/17/2025

Sorry to say this is the last ARRL Propagation Forecast Bulletin I
will write.ÿ I took over in 1991 from Ed Tilton, W1HDQ when he was
too ill and weak to continue, and now with ALS I have similar
problems.

Geomagnetic influencers were more stable this week (planetary A
index shifted from 16.9 to 10.7) and solar indicators were weaker.
Average daily sunspot number changed from 159.1 to 103.3 and average
daily solar flux from 184.3 to 161.9.

Predicted activity indicates solar flux at 210 on January 17-18, 215
on January 19, 220 on January 20-21, 215 on January 22, 220 on
January 23-24, 170 on January 25-26, 175 on January 27-28, 170 on
January 29-30, then 165 and 160 on January 31 through February 1,
155 on February 2-3, 150 on February 4-6, 145 on February 7-8, 150
on February 9, 145 on February 10-12, 150 on February 13, 155 on
February 14-15, 160 on February 16, and 165 on February 17-20.

The forecast for planetary A index is 15, 12 and 8 on January 17-19,
8 on January 20-21, 5 on January 22-30, then 20 on January 31
through February 2, then 15, 12, 12 and 10 on February 3-6, then 5
on February 7-9, 8 on February 19-11, 5 on February 12, 8 on
February 13-16 and 5 on February 17-26.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, January 16, 2025, from F. K. Janda, OK1HH:

"There is no indication that the prediction of an upsurge in solar
activity starting in mid-January will come to pass. The development
is quieter, with no major solar flares occurring. The sunspot groups
that are currently observable from Earth have stable magnetic
fields. More important flares are therefore rather unlikely.

"The geomagnetic field, while not calm, is not disturbed. Intervals
of quiescence alternate irregularly with slight upswings in
activity. Ionospheric shortwave propagation conditions are therefore
not as good as we had hoped based on the predicted rise in solar
activity, but they are not bad either. This type of development is
likely to continue."

The latest from the Royal Observatory of Belgium:

https://www.sidc.be[1]

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation[5] . More good
information and tutorials on propagation are at http://k9la.us/[6] .

Also, check this QST article:

https://bit.ly/3Rc8Njt[7]

"Understanding Solar Indices" from September 2002 QST.

Instructions for starting or ending email subscriptions to ARRL
bulletins are at http://arrl.org/bulletins[8] .

Sunspot numbers for January 9 through 15, 2025 were 126, 105, 85,
99, 100, 106, and 102 with a mean of 103.3. 10.7 cm flux was 162.2,
156.9, 156, 158.4, 159.7, 166.4, and 173.5 with a mean of 161.9.
Planetary A index was 10, 12, 7, 7, 11, 12 and 16, with an average
of 10.7. Middle latitude A Index was 9, 11, 5, 6, 9, 10, and 11,
with a mean of 8.7.

ÿ


[1] https://www.sidc.be
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://arrl.org/w1aw-bulletins-archive-propagation
[6] http://k9la.us/
[7] https://bit.ly/3Rc8Njt
[8] http://arrl.org/bulletins

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS