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ARRL Propagation Bulletin ARLP046 (2022)

ARLP046 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 46  ARLP046
From Tad Cook, K7RA
Seattle, WA  November 18, 2022
To all radio amateurs 

ARLP046 Propagation de K7RA

At 0334 UTC on November 18, the Australian Space Weather Forecast
Centre issued this geomagnetic disturbance warning:

"A moderately large coronal hole will rotate into a geoeffective
location by 19-Nov. Combined with possible weak glancing interaction
of recent CMEs, geomagnetic activity is expected in the coming days.


Sunspot numbers and solar flux did not seem to correlate this week.
Flux rose, while spots fell.

Average daily sunspot number declined from 79.8 to 72.3, but average
solar flux rose from 129.9 to 137.2.

This suggests the number and area of sunspots was less, but the 10.7
cm radiation from those spots increased.

A new sunspot emerged on November 10, another on November 13, and
two more on November 16, the last day of our reporting week, which
runs Thursday through the following Wednesday. Another sunspot group
emerged the next day on November 17.

How is this sunspot cycle progressing? One year ago, in our bulletin
average daily sunspot number was only 36.4, solar flux was 89.1, so
if the latest activity seems a bit lackluster, we can see the cycle
making steady progress. Solar Cycle 25 is expected to peak around
July 2025, about 32 months from now.

So why do we care about these numbers? We get better HF propagation
at higher frequencies when x-rays from the Sun are more intense, and
they correlate with sunspot numbers and the 10.7 cm radiation. This
radiation charges the ionosphere, increasing density.

Back in 1957-59 at the peak of Solar Cycle 19 the radiation was so
intense that (I've been told) 10 meters was open worldwide, around
the clock. Solar Cycle 19 had by far the highest sunspot count in
recorded history, with nothing like it before or since.

Here is the prediction for solar flux, from Thursday which has lower
short term numbers than the Wednesday forecast presented in the ARRL

Expect 118 on November 18-21, 120, 122 and 122 November 22-24, 115
on November 25-26, then 120 and 125 on November 27-28, 130 on
November 29-30, 135 on December 1-12, 120 and 110 on December 13-14,
then 105 on December 15-18, 110 on December 19, and 115 on December
20-23, then back to 135 before the New Year.

Predicted planetary A index, which gives us a clue to possible
geomagnetic unrest, is 10, 18, 28, 12 and 8 on November 18-22, 5 on
November 23-24, then 15, 18, 12 and 8 on November 25-28, 5 on
November 29-30, then 12, 18 and 8 on December 1-3, 5 on December
4-7, 8 on December 8-9, 5 on December 10-11, 10 on December 12-13, 5
on December 14-16, 15 on December 17, then 18 on December 18-19, and
5, 8, 15, 18, 12 and 8 on December 20-25.

Coming up is the annual ARRL 10 Meter Contest, over the weekend of
December 10-11. Expect better propagation than we saw in 2020 and
2021. Although predicted solar flux is not particularly high, the
prediction above shows the highest solar flux (135) over that
weekend, and planetary A index at a low value of 5, indicating
predicted geomagnetic stability. But of course, things may change.

The comment above about Solar Cycle 19 in the ARRL Letter brought
this response, from a ham who was there, and just in time for
Friday's bulletin.

Roger, K6LMN in Los Angeles, California wrote:

"10 meters SSB and the beacons most days are very good. South
America comes as if over a coax cable terminating here in Los
Angeles.  But I need 6 more countries worked/confirmed on 10M SSB to
make 150.

"Also please wake up the 'magic band' 6m because I need a few more
grids on 6M SSB to make 425 confirmed.

"Solar Cycle 24 was OK on 6M and I'm hoping 6M goes wide open this
Solar Cycle 25, after all I am 84 years old and probably this is my
last solar cycle.

"I need more Euro stations and am sorely lacking on the Middle East
and parts of Africa. I cannot compete with you East Coasters.
Namibia was coming in the other day, but the Midwest and east
coasters fought it out. No luck so I gave up. Ah, but I get even
with you easterners since the Pacific area is a piece of cake here
in Los Angeles.

"About Solar Cycle 19. I was a teenager when licensed in 1955 as a
Novice. I heard stations from all over the world on HF and 6M. I
hurried up and got my Tech license and then my General a few years

"HF and 6M stations were coming in 24/7 from all over the world. I
only had 90 watts and a dipole, all on AM, but WOW the stuff I
worked and heard was just incredible.  Mostly peaking around

OK1HH writes:

"Over the past two weeks, several active regions crossed the solar
disk, the most significant was the trio of AR3140, AR3141 and
AR3145, which crossed the central meridian on November 10-11.

"Most attention was drawn to the magnetically complex and almost
daily flare-producing AR3141, which allowed a smaller version of
itself to grow in its northwestern part. The result (see ) reminded fans of 'Hitchhiker's Guide to the
Galaxy President Zaphod Beeblebrox.'

"The solar flux has not dropped below 130 sfu since November 5,
while the Earth's magnetic field has been quiet since November 9.
The result has been a relatively long period of above-average
shortwave propagation conditions.

"Beginning November 17, we expected an increase in geomagnetic
activity as a consequence of, among other things, the CME of
November 14. However, there will likely be a delay of a day or two
from the original forecast. Therefore, if the disturbance begins on
November 18 or 19, preferably during the daylight hours, there may
be further improvement in conditions, and deterioration in the next
phase of the disturbance."

ARRL SSB Sweepstakes is this weekend. Even if you are not a serious
contest operator, it is easy and fun to give out fresh contacts to
stations on the air, especially toward the end of the event when
participants are eager for new, fresh stations.

A new report from Dr. Tamitha Skov, WX6SWW:

Here is a video that makes it appear there is a Sun serpent:

Thanks to reader David Moore for the following online stories on
solar activity:

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 November 10 through 16, 2022 were 79, 57, 65,
74, 77, 69, and 85, with a mean of 72.3. 10.7 cm flux was 138.7,
137.6, 138.2, 137, 141.5, 134.2, and 132.9, with a mean of 137.2.
Estimated planetary A indices were 2, 9, 5, 7, 4, 2, and 2, with a
mean of 4.4. Middle latitude A index was 2, 9, 3, 6, 3, 2, and 2,
with a mean of 3.9.


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