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ARRL Propagation Bulletin ARLP005 (2022)

ARLP005 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 5  ARLP005
From Tad Cook, K7RA
Seattle, WA  February 7, 2022
To all radio amateurs 

ARLP005 Propagation de K7RA

Our Sun was much more active over the past week, with average daily
sunspot number more than doubling from 39.6 in the previous week to
81.3 in the current reporting week, January 27 to February 2.

Geomagnetic indicator average daily Planetary A index changed from
8.3 to 10.1, while average middle latitude A index was unchanged at

Predicted solar flux for the near term is 126, 130 and 125 on
February 4-6, 120 on February 7-10, 128 on February 11-12, 125 on
February 13-14, 120 on February 15-17, 128 on February 18-21, 125 on
February 22-25, 128 on February 26, 132 on February 27-28, 135 on
March 1-3, 125 on March 4-7, 128 on March 8-11 and 125 on March

Predicted planetary A index is 12, 20, 18 and 10 February 4-7, 5 on
February 8-10, 8 on February 11, 5 on February 12-16, then 10, 12, 8
and 5 on February 17-20, then 10, 8, 5 and 8 on February 21-24, then
12, 8, 5 and 8 on February 25-28, then 10, 5 and 5 on March 1-3, 20
and 12 on March 4-5, 5 on March 6-8, then 12 and 8 on March 9-10,
then 5 on March 11-15, then 10, 12 and 8 on March 16-18.

From F.K. Janda, OK1HH:

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, February 3, 2022

"The solar radio flux of 130 and the daily sunspot number up to SSN
of 100 at the end of January, compared to the equal heliographic
length in past solar rotations, showed how unreliable the
twenty-seven-day quasi-periodicity as the guideline for the
predictions can be. 

"The M1 solar flare in AR2936 on January 29th was also a surprise,
which because of the magnetic configuration we did not expect. On
the contrary, it was no surprise that the accompanied LDE, which
triggered halo CME, was followed by an intensification of the solar
wind and an increase in the Earth's geomagnetic field activity. A
major storm was expected on February 2nd. However, it arrived a day
later, on 3rd, including major changes in the parameters of the
Earth's ionosphere in the form of its positive phase around noon

Interesting new Solar Cycle 25 update, thanks to K9LA and K1HTV:

Also, a comment from Dr. Ron Turner of ANSER Research Institute in
Virginia, via He thinks it may be too early to
expect a strong Solar Cycle 25.

This graph shows why Turner is skeptical:

"Solar Cycle 25 is doing something interesting. It is mimicking old
Solar Cycle 24 (SC24). 

"I took sunspot numbers from the early years of SC24 (the red dashed
line) and overlaid them on SC25," says Turner. "They're an almost
perfect match."

"This is significant because Solar Cycle 24 went on to become the
weakest solar cycle in a century. Its hot start did not lead to a
strong maximum. Turner isn't saying that Solar Cycle 25 will
likewise be a dud. But, rather, "these early sunspot numbers are not
enough to guarantee a strong cycle."

David Moore shared this article about a big solar event over 9,000
years ago discovered via ice core analysis:

Update from Dr. Tamitha Skov, WX6SWW:

If you would like to make a comment or have a tip for our readers,
please email the author at,

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

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

Sunspot numbers for January 27 through February 2, 2022 were 85, 77,
74, 70, 100, 88, and 75, with a mean of 81.3. 10.7 cm flux was
107.1, 113.4, 125.3, 129.6, 129.5, 128.6, and 128.2, with a mean of
123.1. Estimated planetary A indices were 7, 8, 17, 10, 10, 7, and
12, with a mean of 10.1. Middle latitude A index was 5, 5, 7, 7, 3,
10, and 8, with a mean of 6.4.


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