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ARRL Propagation Bulletin ARLP051 (2018)

SB PROP @ ARL $ARLP051
ARLP051 Propagation de K7RA

ZCZC AP51
QST de W1AW  
Propagation Forecast Bulletin 51  ARLP051
From Tad Cook, K7RA
Seattle, WA  December 21, 2018
To all radio amateurs 

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

On Wednesday, December 19 Spaceweather.com displayed this headline:
"Solar minimum conditions are in effect," followed by "The Sun has
been without sunspots for 209 days in 2018--that is, 59% of the
time. To find a similar stretch of blank Suns, you have to go back
to 2009 when the Sun was experiencing the deepest solar minimum in a
century."

Looking at my own records, I show the average daily sunspot number
for all of 2009 was 5.05, and average daily solar flux was 70.6.

Looking at the past two months (October 19 through December 19) the
same values were 3.6 and 69.4, so we are clearly down in the same
sort of minima.

Of course, there are many ways to slice and dice the numbers, so
rather than 3.6 and 69.4 from the past two months, looking at all
the numbers for 2018 so far, we see averages of 6.6 and 69.9.

Average daily sunspot numbers for the past week were 3.4 (there were
only two days with any visible sunspots) which was down from 9.7 in
the previous week.

Average daily solar flux declined only slightly from 70.7 to 70.4.

Average planetary A index decreased from 8 to 4.1, while average
mid-latitude A index went from 6.4 to 3.

Predicted solar flux for the next 45 days is 70 on December 21-23,
72 on December 24, 70 on December 25-27, 72 on December 28 through
January 4, 70 on January 5-16, 72 on January 17-31, and 70 on
February 1-3.

Predicted planetary A index is 8, 5 and 5 on December 21-23, then 8,
5 and 5 again on December 24-26, then 8 on December 27-28, then 12,
10 and 8 on December 29-31, 5 on January 1-2, then 10, 12, 10, 10
and 8 on January 3-7, 5 on January 8-12, 8 on January 13, 5 on
January 14-23, then 8, 12, 10 and 8 on January 24-27, 5 on January
28-29, then 10, 12, 10, 10 and 8 on January 30 through February 3.

Geomagnetic activity forecast for the period December 21 to January
16, 2019 from F.K. Janda, OK1HH.

"Geomagnetic field will be:
Quiet on December 23, 25-27, January 10-12
Quiet to unsettled on December 21-22, 24, January 9, 13
Quiet to active on December 28, January 1-2
Unsettled to active on December 29, (31), January (3-5,) 6-8, 14
Active to disturbed on December (30,) January (15-16)

"Solar wind will intensify on November 30 and on December (24-27,)
28-31, January 1, (3-4,) 5-7, (8, 14,) 15-16

"Remark: - Parenthesis means lower probability of activity
enhancement."

Here is an exchange between W8BYA and N0JK about their activity
during the Geminid meteor shower, which peaked on December 14:

"Hi Jon, so excited just had to share with you. After over 6-7 years
of trying KE7NR/P in DM54ah and myself completed on 2m MS using
MSK144 several days before the Geminid peak date. I had a good
feeling when right off the bat I received this +20 dB decode from
him:

"150700  20 20.2 1527 &  W8BYA KE7NR DM54

"Anyway, this was very late AM and represents my best 2m non-EME DX
at 1425 miles and non-EME grid #373.

"Gedas, W8BYA

"I ended up with 9 Geminids m/s Qs on 6 meters. All MSK144. Best DX
probably W3CP EM74. Some fairly short distance M/S Qs such as KV5W
EM22 and K0TPP EM48. Saw decodes on K0WDO EM17, N0LWF EN10, and
several on KA9CFD EN40 - which are fairly close in and would imply
high MUF. I was on early morning Dec. 14.

"100 w, 3 el Yagi.

"Jon N0JK"

The latest from Dr. Tamitha Skov, the Space Weather Woman:

https://youtu.be/wt-T-mbt5Ag

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net .

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,
http://arrl.org/propagation-of-rf-signals. For an explanation of
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere.

An archive of past propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. More good
information and tutorials on propagation are at http://k9la.us/.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.

Sunspot numbers for December 13 through 19, 2018 were 0, 12, 12, 0,
0, 0, and 0, with a mean of 3.4. 10.7 cm flux was 70.2, 70.8, 71.2,
69.8, 70.1, 70.4, and 70.2, with a mean of 70.4. Estimated planetary
A indices were 3, 3, 2, 2, 6, 7, and 6, with a mean of 4.1.
Estimated mid-latitude A indices were 2, 3, 1, 1, 5, 5, and 4, with
a mean of 3.
NNNN
/EX

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