Propagation Update de K7RA

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Propagation Forecast Bulletin 51  ARLP051ARRL Logo
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:

Her report from last weekend can be found here:

 

 

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

ARRL is the national association for Amateur Radio in the US. Founded in 1914 by Hiram Percy Maxim as The American Radio Relay League, ARRL is a noncommercial organization of radio amateurs.

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