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ARRL Propagation Bulletin ARLP001 (2020)

ARLP001 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 1  ARLP001
From Tad Cook, K7RA
Seattle, WA  January 3, 2020
To all radio amateurs 

ARLP001 Propagation de K7RA

Sunspots appeared recently, all indicating Solar Cycle 25 due to
their polarity, opposite from spots in Solar Cycle 24. Sunspots
appeared December 24-26, and it looks like a new Solar Cycle 25 spot
on January 1.  NOAA did not report it (too weak?) but reported a sunspot number of 11 on January 1.

On January 2 NOAA reported the new spot with a sunspot number of 23.

Sorry, but the final propagation bulletin of 2019 was not sent out
due to a misunderstanding on my part, so the usual paragraph of
numbers at the bottom of this bulletin has an additional paragraph
for last week.

Predicted solar flux for the next 45 days is higher than recent
forecasts. Solar flux is predicted at 72 on January 3-10, 70 on
January 11, 72 on January 12-25, 70 on January 26 through February
7, and 72 on February 8-16.

Predicted planetary A index is 5 on January 3-13, then 12 on January
14-15, 5 on January 16-25, 8 on January 26-28, 5 on January 29
through February 9, 10 on February 10-11, and 5 on February 12-16.

Geomagnetic activity forecast for the period January 3-29, 2020 from
F.K. Janda, OK1HH.

"Geomagnetic field will be
quiet on January 3-4, 8, 29
quiet to unsettled on January 5-7, 9-13, 18-21, 25-28
quiet to active on (January 14, 17, 22-24)
unsettled to active on (January 15-16)

"No active to disturbed days predicted. 

"Solar wind will intensify on January (14,) 15-16, (17, 22-24).

"Parenthesis means lower probability of activity enhancement.

"Everything suggests that we are very, very close to the minimum of
the 11-year cycle."

Dick, K1HC wrote on December 31:

"I was on FT8 on 2 meters yesterday from the home QTH in FN42 (400
watts and four 12 element yagis) at about 1630 UTC, and I was
watching the PSK Reporter website to see if I was reaching any other
stations active on FT8. I saw that K2DRH in EN41 had received my FT8
signal at -14dB. With that being over 900 miles away, I went to the
ON4KST chat page and tried to contact K2DRH there without luck. He
was logged in but may have been tied up or away from the computer.

"I am wondering if it was a meteor scatter long burn rather than
sporadic-E propagation. However, I switched to MSK144, and I did not
see any pings from any other stations. I went to higher power, about
700 watts, and had no further spots on the PSK Reporter from the

"I thought you would be interested in the unusual propagation. I
will hope for more of it during the ARRL VHF contest in January from
FN53 in Maine!"

Goodness! 48 elements in phase and 400 watts with FT8? With that
gear, seems like anything may be possible.

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

For more information concerning 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

Monthly propagation charts between four USA regions and twelve
overseas locations are at

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

Sunspot numbers for December 19 through 25, 2019 were 0, 0, 0, 0, 0,
24, and 23, with a mean of 6.7. 10.7 cm flux was 69.9, 70, 70.6, 71,
72.6, 72.7, and 72.1, with a mean of 71.3. Estimated planetary A
indices were 13, 5, 5, 4, 4, 3, and 4, with a mean of 5.4. Middle
latitude A index was 12, 4, 4, 2, 2, 2, and 3, with a mean of 4.1.

Sunspot numbers for December 26, 2019 through January 1, 2020 were
11, 0, 0, 0, 0, 0, and 11, with a mean of 3.1. 10.7 cm flux was
72.1, 72.4, 72.2, 72, 70.9, 70.5, and 71.8, with a mean of 71.7.
Estimated planetary A indices were 5, 3, 2, 2, 3, 4, and 3, with a
mean of 3.1. Middle latitude A index was 3, 2, 0, 0, 2, 4, and 3,
with a mean of 2.


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