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ARRL Propagation Bulletin ARLP003 (2017)

SB PROP @ ARL $ARLP003
ARLP003 Propagation de K7RA

ZCZC AP03
QST de W1AW  
Propagation Forecast Bulletin 3  ARLP003
From Tad Cook, K7RA
Seattle, WA  January 20, 2017
To all radio amateurs 

SB PROP ARL ARLP003
ARLP003 Propagation de K7RA

Last week's Propagation Forecast Bulletin ARLP002 featured zero
sunspots for the entire seven days.

This week (January 12-18) the average daily sunspot number rose to
22.6.

Average daily solar flux rose from 72.5 to 77.1. Average planetary A
index declined from 14.3 to 6.

Predicted solar flux is 80 on January 20-23, then 78, 77 and 75 on
January 24-26, 77 on January 27 through February 1, 76 on February
2, 75 on February 3-8, 76 on February 9, 77 on February 10-14, 78 on
February 15, 80 on February 16-21, 78 on January 22, and 77 on
January 23-28.

Predicted planetary A index is 15, 12, 10 and 8 on January 20-23, 5
on January 24-26, then 12, 15, 7, 10, 12 on January 27-31, then 16,
18, 20, 16, 12, 10 and 8 on February 1-7, and 5 on February 8-12,
then 8, 22 and 18 on February 13-15, 16 on February 16-18, then 12
and 8 on February 19-20, then 5 on February 21-22 and 12, 15, 7 and
10 on February 23-26.

"Geomagnetic activity forecast for the period January 20-February
15, 2017 from F.K. Janda, OK1HH.

"Geomagnetic field will be:
Quiet on January 25-26, February 10, 13-14
Mostly quiet on January 24, 30, February 6, 9, 11-12
Quiet to unsettled on January 23, 27, 31, February 1, 3
Quiet to active on January 20-22, 28-29, February 7-8
Active to disturbed on January February 2, 4-5, 15

"Amplifications of the solar wind from coronal holes are expected on
January 20-21, (22-25,) 26, (31,) February (1-5,) 9, (15)

"Remarks:
- Parenthesis means lower probability of activity enhancement.
- Observed indicia of upcoming MAJOR CHANGES in solar activity!
  Therefore, the current forecast is less reliable.

"F. K. Janda, OK1HH"

Time now to examine the average daily sunspot number for 2016, which
was 36.8. Starting from Solar Cycle 24 minimum in 2008, annual
average daily sunspot numbers were 4.7, 5.1, 25.5, 80.1, 82.3, 97.1,
121.2, 70.1 and 36.8.

The January 11, 2017 issue of ARRL Contest Update (current and back
issues available at http://www.arrl.org/contest-update-issues )
mentions a new online propagation prediction program from G4FKH via
RSGB. The link to ITURHFprop is at http://bit.ly/2jTVHFQ .

The Atacama Large Millimeter/submillimeter Array (ALMA) telescope in
Chile is providing new detailed images of the Sun. See
http://bit.ly/2ka6JKh for details.

More info from regular contributor David Moore:

https://www.sciencedaily.com/releases/2017/01/170117101835.htm

John Kelley, K4WY wrote on January 17:

"Great timely info as always thank you! I wanted to share with you
that on January 2 on 17 meters I worked E51DMC, VK2DX and ZL4FF all
within a spread of an hour. I was in VA and running 100 watts to a
loop and was really surprised when I checked the SN count, A and K
indexes.  Could not have been much worse! So - I am at a loss as to
how to explain the propagation! But I liked it at least for that
hour. 73."

The sunspot number was 0 on that date, and the day prior. There was
one brief sunspot appearance the next day, then none at all from
January 4-11. But given those numbers and daily solar flux (around
72-73) there should be some pretty good propagation during that
period. W6ELprop predicts for that date that ZL4FF might receive
your 17 meter, 100 watt signal from 1530-1930z fairly reliably.

To VK2DX the prediction shows good propagation 1800-2100z. To E51DMC
(South Cook, I assume?) it looks good on 17 meters from 1700-2030z.

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 January 12 through 18, 2017 were 11, 24, 25, 23,
24, 26, and 25, with a mean of 22.6. 10.7 cm flux was 75.5, 74.9,
76.6, 77.5, 78.3, 78.6, and 78.6, with a mean of 77.1. Estimated
planetary A indices were 5, 4, 4, 5, 3, 4, and 17, with a mean of 6.
Estimated mid-latitude A indices were 3, 3, 3, 2, 2, 3, and 11, with
a mean of 3.9.
NNNN
/EX