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The K7RA Solar Update

Spaceweather.com reports that Wednesday, December 11 was the 28th consecutive day with zero sunspots. To date in 2019, 77% of days had no sunspots. Compare this to the previous solar minimum, when 2008 had zero sunspots on 73% of days and 2009 the number of spotless days stood at 71%.

Average daily solar flux this week (December 5-11) was 70.7, up marginally from the previous week when average flux values were 70.2.

At the bottom of the solar cycle there is hardly any geomagnetic activity, with average daily planetary A index at 3.7 and average middle latitude A index at 1.9. That is very quiet and is favorable to propagation on 160 meters.

Just like the report in last week’s bulletin, predicted solar flux is 70 on each of the next 45 days, through January 26.

Predicted planetary A index is 5 on December 13-16, then 8, 12, 8, 8 and 10 on December 17-21, 5 on December 22 through January 4, 8 on January 5, then 5 on January 6-8, then 8 on January 9-10, 5 on January 11-13, 12 on January 14, 10 on January 15-17, and 5 on January 18-26.

Geomagnetic activity forecast for the period December 13, 2019-January 07, 2020 from F.K. Janda, OK1HH.

Geomagnetic field will be:
Quiet on: December 15-17, 28-31, January 1-4
Quiet to unsettled on: December 23-25
Quiet to active on: December (13-) 14, 22, January 7
Unsettled to active on: December 18, 21, (26-27,) January 5-6 active to Disturbed: (19-20)

Solar wind will intensify on: December (13-14, 16,) 18-21, (26,) January 7

Parenthesis means lower probability of activity enhancement. Everything suggests that we are very close to the minimum of the 11-year cycle at present stage of development.

G4KSG reported on December 9 at 0900 UTC hearing a conversation on 20-meter SSB between an EA7 and JA3, with his dipole at 30 feet. Checking W6ELprop on that date it looks like signals between Spain and Japan would peak (just barely) around 0730 UTC but fade by 0900. Between England and Japan signals would be peaking around 0700-0800 UTC, then fading. From Spain to England, signals might be marginal at 0900, but then improving with the best time from 1030-1400 UTC. So even with no sunspots, propagation still happens.

K6XC reported on December 9 that 10 meters appeared dead, but at 2020 UTC he worked ZL1SW using FT8. He used a hexbeam at 40 feet pointed at 60 degrees. Short path to ZL1SW from K6XC is 226.7 degrees, and long path is 46.7 degrees.

Two recent articles from Nature on the Parker Solar Probe: https://www.nature.com/articles/d41586-019-03665-3 and https://www.nature.com/articles/d41586-019-03684-0

The ARRL Ten Meter Contest is this weekend, starting Friday night in North America. Check http://www.arrl.org/contests

Although we are currently at solar minimum, conditions may be enhanced by the Geminids meteor shower. Monitoring http://www.livemeteors.com/ suggests a fair amount of activity. Check this for more information on how this service works: http://www.livemeteors.com/how-does-this-work

Check this out: a new prediction for the end of Cycle 24 and new Cycle 25: https://bit.ly/2Eavjms

K8MKN wrote: “Here’s a suggestion, especially with all these zero reports of sunspots. Can you do a flashback to what the sunspot readings were a year ago or two years ago, or maybe 11 years ago? It might be interesting to put it in context with what’s going on today.”

Here are the bulletins from 2013-2018, with sunspot numbers toward the bottom: http://www.arrl.org/w1aw-bulletins-archive/ARLP050/2018

http://www.arrl.org/w1aw-bulletins-archive/ARLP050/2017

http://www.arrl.org/w1aw-bulletins-archive/ARLP050/2016

http://www.arrl.org/w1aw-bulletins-archive/ARLP050/2015

http://www.arrl.org/w1aw-bulletins-archive/ARLP050/2014

http://www.arrl.org/w1aw-bulletins-archive/ARLP050/2013

They show average daily sunspot numbers (working backwards) of 9.7, 2.3, 40.9, 48, 88.4, and 102.9.

The latest video from WX6SWW: https://www.youtube.com/watch?v=HzA57ZxBspY&t=8s

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 http://www.arrl.org/propagation and the ARRL Technical Information Service 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 5 through 11, 2019 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 70.7, 70.3, 70.2, 71.6, 70.7, 70.6, and 70.7, with a mean of 70.7. Estimated planetary A indices were 3, 4, 2, 3, 4, 4, and 6, with a mean of 3.7. Middle latitude A index was 1, 2, 1, 2, 2, 2, and 3, with a mean of 1.9. (arrl.org)

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