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ARRL Propagation Bulletin ARLP051 (2017)

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 29, 2017
To all radio amateurs 

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

There were no zero-sunspot days over the past reporting week,
December 21-27. Then on Thursday, December 28 there were no
sunspots.  So far in 2017 there have been 102 days with no sunspots,
or 28%.
 
Average daily sunspot number was 17.4, up from 2.3 the previous
seven days. The previous week had such a low average because only
one day out of that week had any sunspots at all. That was December
20 with a sunspot number of 16.
 
Average daily solar flux was 74.6, up from 71.5 the previous week.
 
Average daily planetary A index declined from 9.4 to 7.1, while
average mid-latitude A index went from 6.1 to 5.7.
 
We probably will not observe a return of any sunspots until at least
January 5, when predicted solar flux is expected to increase
slightly from 68 to 72.
 
Predicted solar flux for the next 45 days is 70 on December 29-31,
68 on January 1-4, 72 on January 5-12, 74 on January 13, 75 on
January 14-25, 74 on January 26, 72 on January 27 through February
8, 74 on February 9 and 75 on February 10-11.
 
Predicted planetary A index is 5, 5, 10, 25, 15 and 8 on December 29
through January 3, 5 on January 4-6, then 10, 12 and 6 on January
7-9, 5 on January 10-12, then 22, 16, 20, 16, 10, 8 and 5 on January
13-19, 12 on January 20-21, 8 on January 22, 5 on January 23-26,
then 10, 25, 15 and 10 on January 27-30, 5 on January 31 to February
2, then 10, 12 and 6 on February 3-5, 5 on February 6-8, then 22, 16
and 6 on February 9-11.
 
Here is the geomagnetic activity forecast for December 29, 2017 to
January 24, 2018 from F.K. Janda, OK1HH.
 
"Geomagnetic field will be: 
Quiet on December 30, January 5, 11, 17-18, 23-24 
Mostly quiet on December 29, January 4, 6, 19, 
Quiet to unsettled on January 7-8, 10, 16, 
Quiet to active on December 31, January 2-3, 12, 14-15, 22 
Active to disturbed on January 1, 9, (13, 20-21) 
 
"Amplifications of the solar wind from coronal holes are expected on
December 31, January 1-3, (6-8,) 10-13, 19-20, (21-22).
 
"Parenthesis means lower probability of activity enhancement."
 
Jeff Hartley, N8II of Shepherdstown, West Virginia (FM19ck) reported
on December 22:
 
"We had some excellent low bad conditions on the evenings of
December 20-21 allowing QSOs with S01WS in Western Sahara, Finland,
Sweden, EU Russia, Lithuania, Romania, and Ukraine on 160M with best
signals mostly around 2400Z and 0100Z. On 80M, Russia, Latvia,
Lithuania, Greece, Poland, Hungary, Slovenia, and Romania were
worked. Many signals on 80 were at least S9 as were several on 160.
 
"Today, December 22, 15M opened late to Europe allowing a very solid
S9 QSO with EA7ATX at 1603Z on 15 phone; followed by S9+15dB with
MI5AFK in Northern Ireland. England and VO1CAL in Newfoundland were
also worked on SSB and Hungary on CW. There could have been some
sporadic-E involved, not sure."
 
Dr. Tamitha Skov is featured in the first 2018 issue of Popular
Science:
 
https://www.popsci.com/space-weather-woman
 
Her report from last weekend can be found here:
 
https://www.youtube.com/watch?v=YJnQvu0FZ-E
 
The latest report should be posted here soon:
 
https://www.youtube.com/user/SpWxfx
 
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 21-27, 2017 were 18, 18, 22, 22, 17,
14, and 11, with a mean of 17.4. 10.7 cm flux was 76, 75.3, 76.2,
76.1, 75.7, 71.8, and 71, with a mean of 74.6. Estimated planetary A
indices were 3, 2, 5, 12, 10, 11, and 7, with a mean of 7.1.
Estimated mid-latitude A indices were 2, 2, 4, 9, 9, 8, and 6, with
a mean of 5.7.
NNNN
/EX