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ARRL Propagation Bulletin ARLP004 (2021)

ARLP004 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 4  ARLP004
From Tad Cook, K7RA
Seattle, WA  January 22, 2021
To all radio amateurs 

ARLP004 Propagation de K7RA

We just witnessed twelve consecutive days with no sunspots, which
many of us found a bit unsettling. But fortunately Solar Cycle 25
activity returned with new sunspot 2796 on January 15. Instead of
moving from the east across the solar horizon, it emerged in the
southern hemisphere, just west of center.

Currently we are seeing sunspot regions 2797 and 2798, which emerged
in the southeast, and looking at images from the STEREO spacecraft,
I see another bright spot on the horizon.

Average daily sunspot number increased from 0 last week to 14.7
in this reporting period, January 14-20.

Average daily solar flux rose from 73.8 to 76.1, and geomagnetic
indicators sank to very quiet levels. Average daily planetary A
index dropped from 5.9 to 4, and average daily middle latitude A
index from 4.4 to 3.

The outlook for the next month looks good. Predicted daily solar
flux for the next 30 days is 80 on January 22-28, 75 on January 29
to February 3, 76 from February 4-10, 77 from February 11-17, and 76
on February 18-20.

Predicted planetary A index is 5 on January 22-26, 8 on January
27-28, 5 on January 29-31, 10 on February 1-2, 5 on February 3-13,
then 10, 10, 12 and 10 on February 14-17, and 5 on February 18-20.

Geomagnetic activity forecast for the period January 22 to February
17, 2021 from F.K. Janda, OK1HH.
"Geomagnetic field will be,
quiet on: January 22, 28-30, February 4, 10
quiet to unsettled on: January 23, 27, February 5-6, 9-13, 17
quiet to active on: January 24-26, 31, February 1, 3, 7, 14-16
unsettled to active: February 2, 8
active to disturbed: none
"Solar wind will intensify on: January (25-27, 31,) February (1,)
2-3, (4, 8-10, 15-16).

"- Parenthesis means lower probability of activity enhancement.

"- Now the predictability of changes is much lower than before, as
  there are very ambiguous indications.

"- This forecast was made on the 21st day, the 21st year of the 21st
 century and is valid since 21:21 UTC."

Ken, N4SO in Grand Bay, Alabama reports good results running 1-watt
and an inverted vee on 80 meter CW. On January 15 at 0730 UTC he
worked V31MA in Belize. He is having fun late nights on 30 meters
running FT8 and making worldwide contacts.

Check for the recent propagation talk by K9LA
at the Madison DX Club.

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

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

Sunspot numbers for January 14 through 20, 2021 were 0, 13, 15, 23,
13, 14, and 25, with a mean of 14.7. 10.7 cm flux was 73.6, 73.4,
77.7, 77.2, 75.3, 78.1, and 77.2, with a mean of 76.1. Estimated
planetary A indices were 2, 3, 4, 3, 4, 6, and 6, with a mean of 4.
Middle latitude A index was 1, 2, 2, 2, 3, 6, and 5, with a mean of


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