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ARRL Propagation Bulletin ARLP052 (2020)

ARLP052 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7RA
Seattle, WA  December 28, 2020
To all radio amateurs 

ARLP052 Propagation de K7RA

Merry Christmas.

Sunspots went missing last Friday and Saturday, but large new
sunspot group 2794 appeared on Sunday, December 21, and on Wednesday reported new sunspot group 2795 emerging over our
Sun's southeastern limb.

This disappearance depressed the average weekly sunspot number,
which went from 17.4 last week to 10.3 this week, ending on
Wednesday, December 23.  Our reporting week runs from Thursday
through Wednesday.

In spite of lower sunspot numbers, the average daily solar flux
increased slightly from 82.1 to 82.8.

Average daily planetary A index increased from 4.7 to 7.3, and
average daily middle latitude A index went from 3.3 to 6.  These are
still low numbers, indicating quiet geomagnetic conditions, so 160
meter propagation remains good, also aided by lower seasonal
atmospheric noise as winter begins in the Northern Hemisphere.

Predicted solar flux for the next 30 days is 88 on December 25 to
30, 86 on December 31, 84 on January 1 to 6, 82 on January 7 to 12,
84 on January 13 to 20, and 86 on January 21 to 23.

Predicted geomagnetic indicators for the same period has planetary A
index at 15 and 8 on December 25 and 26, 5 on December 27 through
January 4, 10 on January 5 and 6, 5 on January 7 to 12, 8 on January
13, 5 on January 14 to 16, then 12, 8 and 18 on January 17 to 19,
then 15, 10, 8 and 3 on January 20 and 23.

The OK1HH geomagnetic activity forecast for the period December 25,
2020 til January 19, 2021:

"Geomagnetic field will be 
Quiet on:  January 4, 12 to 14 
Quiet to unsettled on:  December 28 to 31, January 1 to 3, 15 
Quiet to active on:  December 25 to 27, January 6, 8, 10 and 11, 16
Unsettled to active:  January 2, 5, 7, 9, 17, 19 
Active to disturbed:  January 18 

Solar wind will intensify on: December (25,) 27 (28 and 29,)
(January 1 to 3, 7 and 9, 18,) 19
- Parenthesis means lower probability of activity enhancement.
- The predictability of changes is lower again, as there are
ambiguous and changing indications.

I wish you a blessed Christmas, positive thinking and negative
Steve, NN4X reported working a VK and a ZL via 15 meter long path
around 1915 UTC on December 23 using FT8.  NN4X is in Florida,
southeast of Orlando.  His antenna (two stacked 6 element Yagis) is
highly directional, so he has no doubt this was long path.  He was
also heard at 3D2 and KH6.  He writes, "I've been a ham since 1977,
and this stuff never gets boring."

Check out his impressive array of antennas listed on his
page.  He sent a pskreporter screenshot showing he was copied all
over the world, except Asia.

Jeff, N8II wrote on December 19:

"Today, we had 2 contests.  The RAC and 9A CW (Croatia, everybody
works everybody).  15 was a bit marginal into western Canada, but I
worked MB, SK, AB, and BC plus several VE3's on backscatter.  15
meters was open to Southern and Central EU at the 1400 UTC 9A CW
start, but with few loud signals.  By 1500 UTC most activity
disappeared.  20 meter signals were loud from both eastern and
western Canada and Europe, with the band starting to close around
1615 UTC.  My last EU QSOs were with Geoff, GM8OFQ in the Orkney
Islands (S9+10db) and Tom G1IZQ (S9 with QSB) just after 1700 UTC.

Signals from EU have been weaker and openings much shorter on 15
meters in general this past week due to the drop in solar activity.
One day I had a QSO with a loud Norwegian who was S9 around 1400
UTC, but in general most signals have been from southern EU.

Our sunsets are already later here by 3 minutes, but sunrises will
get later until about December 31 due to the elliptical orbit of the
Earth, so openings to the East will get later."

Tamitha Skov's latest:

For more information concerning radio propagation, see and the ARRL Technical Information
Service at  For an
explanation of numbers used in this bulletin, see

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

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

Sunspot numbers for December 17 through 23, 2020 were 12, 0, 0, 11,
11, 11, and 27, with a mean of 10.3.  10.7 cm flux was 81.6, 80.5,
81.7, 83.8, 79.6, 85.8, and 86.4, with a mean of 82.8.  Estimated
planetary A indices were 2, 3, 5, 4, 12, 13, and 12, with a mean of
7.3.  Middle latitude A index was 2, 2, 4, 4, 8, 11, and 11, with a
mean of 6.


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