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ARRL Propagation Bulletin ARLP053 (2016)

ARLP053 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 53  ARLP053
From Tad Cook, K7RA
Seattle, WA  December 30, 2016
To all radio amateurs 

ARLP053 Propagation de K7RA

The Australian Space Forecast Centre issued a Geomagnetic
Disturbance Warning on December 29 at 0010 UTC.

"A recurrent equatorial coronal hole will soon reach geoeffective
location on the solar disk. The size of the current coronal hole is
relatively larger compared to its characteristics during the
previous rotation. The co-rotating interaction region and subsequent
high speed streams associated with the coronal hole is expected to
affect Earth from late 30 December. Auroras may be visible on the
local nights of 30 and 31 December in Tasmania and possibly from the
coastline of Victoria."

The warning said to expect active geomagnetic conditions on December
30 and 31.

The past two and a half weeks have seen seven days with 0 sunspots,
spread over four periods of one to three days each.

The first was December 10, then two days over December 16-17, then
three days on December 23-25 and finally yesterday, December 29.

Over the latest reporting week, December 22-28, average daily
sunspot number was 7.6, down from 11 over the previous seven days.
Average daily solar flux changed only slightly from 73.2 to 73.6.
Average daily planetary A index increased from 7.9 to 17.3 and
mid-latitude A index from 5.7 to 11.6.

Predicted solar flux is about the same as recent indices. 72 on
December 30, 75 on December 31 through January 6, 79 on January 7-9,
77 on January 10-13, 75 on January 14-19, 73 on January 20-23, 75 on
January 24-27, 77 on January 28 through February 1, 79 on February
2-5, and 77 on February 6-9.

Predicted planetary A index is 10, 24, 18, 10 and 12 on December 30
through January 3, 24 on January 4-5, then 16, 14 and 6 on January
6-8, 5 on January 9-13, 10 on January 14, 5 on January 15-16, then
25, 20 and 25 on January 17-19, 18 on January 20-21, 10 on January
22, 5 on January 23-25, then 15, 10, 5, 8, 10 and 20 on January
26-31, then 22, 16, 14 and 6 on February 1-4 and 5 on February 5-9.

We also have a geomagnetic activity forecast from Petr Kolman,
OK1MGW, for the period December 30 2016 to January 25, 2017.

Geomagnetic field will be:
Quiet on January 10-12
Mostly quiet on January 8-9, 25
Quiet to unsettled on January 1-3, 13-16, 23-24
Quiet to active on December 30 January 6-7, 17-20
Active to disturbed on December 31, January 4-5, 21-22
Increased solar wind from coronal holes expected on December 30-31,
January 4-7, and then 17-22.

Bob Hillman, AG6XC/VE7EK wrote:

"I find the reports of value and look forward to each one.

"While I take the time to dig into the science, I've developed a
fondness for the candid comments of hams reporting their personal

"All are different and reading them reminds me why I developed a
life-long interest in the hobby.  I like hearing from the guy who
perseveres and finds some DX with a limited station and limitless

"It keeps alive some of the 'mystery' and 'magic' of the art, with
some unique stories of success, even in light of poor HF propagation

"Warmest wishes for a Merry Christmas and a Happy New Year!"

Don't forget, Straight Key Night happens this weekend. Unpack your
old J-38, Speed-X or Lionel (or any other) straight key and put it
on the air. Details at .

Here are a few images of straight keys to whet your appetite for

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 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 22 through 28 were 12, 0, 0, 0, 13, 14,
and 14, with a mean of 7.6. 10.7 cm flux was 74.8, 73.7, 73.1, 72.5,
73.8, 73.7, and 73.3, with a mean of 73.6. Estimated planetary A
indices were 23, 24, 14, 21, 22, 11, and 6, with a mean of 17.3.
Estimated mid-latitude A indices were 15, 17, 10, 12, 15, 8, and 4,
with a mean of 11.6.


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