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ARRL Propagation Bulletin ARLP003 (2024)

ARLP003 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 3  ARLP003
From Tad Cook, K7RA
Seattle, WA  January 19, 2024
To all radio amateurs 

ARLP003 Propagation de K7RA

Solar activity increased substantially over the past week, with
twelve new sunspot groups. One appeared on January 11, five more on
January 12, another on January 13, two more on January 15, and three
more on January 16.

Two more sunspot groups emerged on January 18.

Average daily sunspot number rose from 146.1 to 167.3, and solar
flux from 163.3 to 184.1.

Geomagnetic numbers remained low and practically unchanged, with
planetary A index moving from 4.9 to 5, and middle latitude A index
shifting from 4.3 to 3.9.

Predicted solar flux is 162, 160 and 155 on January 19-21, then 150
on January 22-23, 152 on January 24-25, 167 on January 26, 170 on
January 27-29, then 175 and 180 on January 30-31, 185 on February
1-4, then 187 and 185 on February 5-6, 170 on February 7-8, 175 on
February 9-10, 190 on February 11-12, then 185, 175, 170 and 165 on
February 13-16, then 162 on February 17-18, then 160, 160, 165 and
167 on February 19-22, and 170 on February 23-25.

Predicted planetary A index is 5, 1, and 10 on January 19-21, then 5
on January 22-27, 8 on January 28-30, 5 on January 31 through
February 11, 8 on February 12-14, and 5 on February 15-23, then 12
on February 24-25.

In an email report on January 14, Jon Jones, N0JK wrote, "Today
there are thirteen sunspot groups on the Earthside of the Sun - the
greatest number so far in Solar Cycle 25. Despite the surfeit of
sunspots, the Sun has been quiet all weekend. Could it be the calm
before the storm? One of the sunspots (AR3541) has a delta-class
magnetic field that poses a threat for X-class solar flares."

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - January 18, 2024 from OK1HH:

"We've had two weeks of mostly quiet conditions, with relatively
high solar activity but only a few flares. And most importantly - no
CMEs hitting the Earth. In addition, 13 sunspot groups were observed
on the Sun on January 13 - the highest number in the current 11-year
cycle. Despite the glut of sunspots, the Sun remained quiet.

"Shortwave conditions were therefore more influenced by changes in
solar wind parameters. The exception was on 15 January, when
shortwave propagation was affected by a sporadic-E layer, which
occurred over Europe before noon UTC and over the USA later in the
afternoon UTC.

"Although solar flares were not massive, they were nevertheless
accompanied by CMEs on several occasions, but were directed away
from Earth. The biggest of these left the Sun on January 14 and was
headed toward Mercury and Venus (these planets can be seen in the
east before sunrise).

"We are now expecting solar flares of C-class at 0-2 per day, with
the rare possibility of a M-class flare. Coronal holes are mostly
small and do not occur near active regions, which also reduces the
likelihood of geomagnetic disturbances. Therefore, it appears that
the current relatively favorable trend will continue."

Bil Paul, KD6JUI in Northern California operates from a fresh water
kayak, and sent this report:

"I was out in the kayak yesterday, January 11, with 10w and a small
loop. With solar flux at 180+ I expected a lot happening on 10m but
that was not the case. Was disappointed. Did get a few contacts.
Heard Chile and Argentina coming in fairly strong (I had no luck
there) and heard very faintly an Israeli station. Best distance I
contacted was Bermuda, a VP9, on CW.

"Went down to 12m and had a few more contacts.

"Quite a bit of QSB on both bands."

Dave, N4KZ in Kentucky reported via email:

"For the second time in the past month I have decoded DX signals on
8 meters. Several countries have authorized their amateurs to
operate on 8 meters. The FT8 frequency is 40.680 MHz. On January 14,
2024, at 1540 UTC I saw a spot for 8 meter activity on the DX Summit
website. As soon as I moved to that frequency, I decoded several DX
signals from Europe and the Caribbean. But within a few minutes
signals faded out.

"About a month ago, I saw an Irish station work an American station
who has an experimental license for 8 meters. No other activity was
heard that time. I know of at least one American on 8 meters with an
experimental license. He's in Georgia. I'm not sure if there are

"I was using my 3-element 6-meter Yagi up 60 feet to listen. On the
two occasions I have decoded European stations, they had good
signals. Offhand, crossing the Atlantic on 40 MHz seems much easier
than at 50 MHz."

Tolvo, W8JTM of Liberty Lake, Washington sent this report:

"The 'Santa Claus Polar Path' described by Carl Luetzelschwab, K9LA
(link follows) is well and good! Not sure if it was winter F2
ionization or Aurora-E, but I had a nice SSB ragchew with OH6RM on
10 meters on 15 January when it was 11 PM Finland time (2100 UTC),
well after the MUF had dropped to not support 28 MHz.

"Signals were 20 dB over S9 with no flutter the whole time, and
after I signed off, I heard him work station-after-station all over
the USA for almost two hours with his signal only dropping to S9.
It was an incredibly solid path for 10 meters from Eastern
Washington, some 4500 miles.

"I also worked into Finland on 17 January on 15 meter phone, but
there was heavy slow flutter on the signals.

"As reported by Carl, these polar paths are surprisingly reliable in
Fall and Winter, and I always enjoy working into Finland where my
parents were from."

From Scientific American, a story about the upcoming Solar Eclipse,
with sunspots this time:

An image of Sunspot AR3545 from Sky and Telescope magazine:

SciTechDaily article about the Solar peak:

An article about a gigantic solar hole:

Explanation of the Babcock Model:

From News Rebeat, the US/Korea to monitor solar storms:

A "Travel and Leisure" article about the Northern Lights with regard
to a Solar max January to October 2024:

Here is the latest report from Dr. Tamitha Skov, WX6SWW:
Send your tips, reports, observations, questions and comments to When reporting observations, don't forget to tell us
which mode you were operating.

For more information concerning shortwave radio propagation, see and the ARRL Technical Information
Service web page 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 .

Also, check this:

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

Sunspot numbers for January 11 through 17 2024 were 151, 188, 191,
183, 150, 150, and 158, with a mean of 167.3. 10.7 cm flux was
192.5, 186.4, 185.4, 187.9, 182.5, 179.6, and 174.1, with a mean of
184.1. Estimated planetary A indices were 6, 4, 3, 6, 6, 6, and 4,
with a mean of 5. Middle latitude A index was 4, 4, 3, 5, 4, 4, and
3, with a mean of 3.9.


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