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ARRL Propagation Bulletin ARLP043 (2023)

ARLP043 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 43  ARLP043
From Tad Cook, K7RA
Seattle, WA  October 27, 2023
To all radio amateurs 

ARLP043 Propagation de K7RA

The recent solar activity decline continues. Weekly average daily
sunspot numbers starting with Propagation Forecast bulletin ARLP039
on September 21 were 170.6, 128.6, 144.1, 89.4, and 41.9 for this

Weekly average daily solar flux for the same period was 168.8,
155.6, 159.1, 145.1 and 123.5.

On October 25 noted "Solar Cycle 25 roared to life
in 2021-23, dashing predictions of a weak solar cycle. Forecasters
have since been expecting a robust Solar Max in 2024 or 2025.
Suddenly, however, sunspot counts are dropping."

But they note that in strong sunspot cycles temporary lulls are
common, and strong activity should resume soon, with a cycle peak
within the next two years.

Forecasters provided a recent link to NOAA:

The next day they wrote, "NOAA has just issued a revised forecast
for Solar Cycle 25. Solar Max is coming quicker and stronger than
previously thought."

From NOAA:

Three new sunspot groups appeared this week over October 20-22.

What is the outlook for the next month?

Predicted solar flux is 126 on October 27-28, 130 on October 29-30,
132 on October 31, 134 on November 1-2, 150 on November 3-5, 140 on
November 6-9, 135 on November 10-11, then 145, 140, 135 and 135 on
November 12-15, 140 on November 16-18, then 135 and 140 on November
19-20, and 145 on November 21-24, and 150 on November 25 through
December 2.

Predicted planetary A index is 16, 8, 5, 20, 18 and 8 on October 27
through November 1,  then 5 on November 2-8, then 12 and 8 on
November 9-10, 5 on November 11-12, 12 on November 13-14, 10 and 8
on November 15-16, 5 on November 17-22, then 8 on November 23-26,
and 10 and 12 on November 27-28, and 5 on November 29 through
December 5.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere from F.K. Janda, OK1HH on October 26, 2023.

"In the last seven days we observed two surprises. For the first
time, after the solar flare of 16 October, we saw a geomagnetic
disturbance on 19 October. But it started on October 18 and
continued to October 20.

"Solar activity gradually decreased, M-class flares ceased, and only
isolated C-class flares continued. By October 23 only two or three
small groups of spots remained on the solar disk.

"On October 21, the Earth's magnetic field activity briefly
increased, which, together with a multi-day decrease in solar
radiation, caused low MUF values and thus shorter intervals of upper
shortwave band openings.

"The geomagnetically quiet development on 22-25 October caused only
a gradual improvement in shortwave propagation conditions. In
addition, the daily MUF values were relatively very low.

"Then, on the 26th, the Earth's magnetic field activity increased.
Positive phase of disturbance started in the daytime UT, accompanied
by an increase in MUF (with a maximum around 1300 UT).

"I don't expect any significant rise in solar activity in October.
It is indeed forecast for November, but even the STEREO satellites,
in service for 10 years, have not yet observed more interesting

N0JK wrote:

"The weekend of Oct 20-22 had some outstanding propagation on 6

"Saturday afternoon October 21 there were Es links to TEP
(Trans-Equatorial Propagation) on toward the South Pacific from the
Midwest. N0LL copied FK8CP and ZL1RS on just a hamstick vertical
while driving from Salina to his home in Smith Center, Kansas. He
later worked E51WL from his home around 2130 UTC.

"I was staying at the La Quinta Inn in Scottsdale for the weekend.
Had my MFJ-9406 along and used a dipole antenna in the hotel room. I
copied N0LL in EM09, N0KQY in DM98 and N0OT in DM88 on 6 meter Es
calling DX stations around 1945 UTC. Es in October are rare, and Es
links rarer still.

"Later that evening I managed to work W5JAY in EM26 on 6m FT8 via Es
at 0136 UTC October 22. Power was 7 watts to the indoor dipole. East
coast stations were working the South Pacific on Es links to TEP.

"That next afternoon Arizona had Es - link to TEP to South America.
I copied XE1H in DL80 at the first Es hop.

"At 2333 UTC on October 22 on 50.313 Rx FT8 copied XE1H in DL80
calling CQ.

"October 24 at 2335 UTC copied PY5CC in GG54 via Es link to TEP.

" noted a CME impact October 20. The active
geomagnetic field boosted the TEP MUF and may have sparked some of
the sporadic-E as well.

"73, Jon, N0JK in DM43 (usually EM28)."

From Mike Schaffer, KA3JAW in Easton, Pennsylvania.

"Two New Continents on 10 meters 29.600 FM.

"The upper end of the 10 meter band (29.600 FM) is still kind of
rough, but on Wednesday, October 18th, 1752 UTC I worked Naama, S01A
(Sierra-Zero-One-Alpha) in Western Sahara, Africa, grid IL56hb, RS:
5x9+ peak both ways. Distance 3607 miles.
"His QRZ page:

"Then on Monday, October 23rd, 2206 UTC worked Hirobumi, JF7AWV in
Kouriyama, Japan, grid PM95vq calling CQ, went back to his call and
he heard me RS: 5x5, he was a RS: 3x3 moderate QSB. Distance 6502
"Just a reminder to operators, please use the ITU Phonetic Alphabet.
It makes picking out your callsign much more rapidly with less
confusion under weak propagation conditions.

"Equipment: Kenwood TS-690S, 80 watts, Cushcraft 10-Meter Ringo 5/8
wave vertical 10 feet off ground."

And I have a reminder to FM operators on 29.6 MHz.

This is the national simplex calling frequency and gets quite busy.
When making contact, I ask the other station to QSY to a simplex
frequency, such as 29.2 MHz. [K7RA]

Latest video from Dr. Tamitha Skov, WX6SWW:

Note that this weekend is the SSB portion of the CQ World Wide DX


Send your tips, reports, observations, questions and comments to When reporting observations, don't forget to tell us
which mode you were operating.

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

Also, check this article from September, 2002 QST:

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

Sunspot numbers for October 19 through 25, 2023 were 39, 56, 65, 48,
25, 34, and 26, with a mean of 41.9. 10.7 cm flux was 128.7, 125.7,
122.6, 118.8, 122.1, 121.1, and 125.8, with a mean of 123.5.
Estimated planetary A indices were 10, 8, 22, 8, 3, 4, and 4, with a
mean of 8.4. Middle latitude A index was 8, 8, 13, 7, 2, 2, and 3,
with a mean of 6.1.


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