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Propagation Forecast Bulletin #45 de K7RA:

Propagation Forecast Bulletin #45 de K7RA:

From : W1AW Bulletin via the ARRL on 2019-11-08

Two new sunspot groups appeared this week, on two consecutive days, each lasting for only a day, with a daily sunspot number of 11 and 13 on Friday and Saturday of last week, just in time for ARRL CW Sweepstakes. Both sunspot groups had a magnetic polarity signature indicating Solar Cycle 25, and appeared after 4 weeks of no sunspots.

Website :
Propagation Forecast Bulletin #45 de K7RA:

ZCZC AP45
QST de W1AW
Propagation Forecast Bulletin 45 ARLP045
>From Tad Cook, K7RA
Seattle, WA November 8, 2019
To all radio amateurs

SB PROP ARL ARLP045
ARLP045 Propagation de K7RA

Two new sunspot groups appeared this week, on two consecutive days, each lasting for only a day, with a daily sunspot number of 11 and 13 on Friday and Saturday of last week, just in time for ARRL CW Sweepstakes. Both sunspot groups had a magnetic polarity signature indicating Solar Cycle 25, and appeared after 4 weeks of no sunspots.

Spaceweather.com reported both appearances as region AR2750, yet NOAA reported a new sunspot group on each day, shown as a 1 in the New Regions column:

ftp://ftp.swpc.noaa.gov/pub/indices/DSD.txt

Perhaps that is true, and the new appearances on each day were both counted as part of AR2750.

Solar flux was higher over the past reporting week (Thursday through Wednesday, October 31 through November 6) with average daily solar flux rising from 68.5 to 70.4.

Average solar flux as reported in this bulletin hasn't been as high since 2019 Propagation Forecast Bulletin ARLP020, back in May, when it was 75.7:

http://www.arrl.org/w1aw-bulletins-archive/ARLP020/2019

Note there were sunspots during that week also.

Geomagnetic indicators were low this week, with average daily planetary A index declining from 16.4 to 4.1, and average mid-latitude A index softening from 13 to 2.7.

Predicted solar flux is 70 on November 8, 68 on November 9-15, 67 on November 16-19, 68 and 70 on November 20-21, 71 on November 22-30, 70 on December 1-6, 69 on December 7-19, and 70 on December 20-22.

Predicted planetary A index is 5 on November 8-9, then 10, 12 and 8 on November 10-12, 5 on November 13-19, then 15, 25, 18, 12 and 10 on November 20-24, 8 on November 25-26, 5 on November 27 through December 16, then 15, 20, and 18, on December 17-19, 12 on December 20-21 and 5 on December 22.

At ftp://ftp.swpc.noaa.gov/pub/forecasts/45DF/ NOAA reported a solar flux forecast of 96 for December 16-18 in their predictions on their November 1-5 forecasts, but when I asked about this, they told me that the US Air Force had transposed digits from 69 to 96. By the November 6 forecast, this was all corrected. Drat! I was hoping for those higher numbers. My contact at NOAA told me he wished the flux would be 96, or even better, 196!

Even during days with no sunspots, there was notable HF propagation recently, with the Pitcairn Island expedition making HF contacts across the Americas, even on 10 meters.

F.K. Janda, OK1HH sent us his geomagnetic activity forecast for the period November 8 to December 3, 2019.

"Geomagnetic field will be
Quiet on: November 13, 18-19, 29-30, December 1
Quiet to unsettled on: November 8-9, 11, 15, 27-28
Quiet to active on: November 10, 12, 14, 16-17, 25-26, December 2-3
Unsettled to active on: November 20, 24
Active to disturbed: November 21-23

"Solar wind will intensify on: November (8-9,) 13, 21-26, (27-29).

"Parenthesis means lower probability of activity enhancement."

Stevie, MI0GTA, from Ireland commented on November 4 about working DX, even with low solar activity:

"I thought you might like to know I worked 15 new DXCC countries on 15m during the CQWW CW DX Contest, Chile, India, South Africa, Afghanistan were some of the best I worked.

"I use a M0PLK delta loop at 11 meters above ground and 350w from my old Yaesu FL2100z amp, rig is a Pro-III.

"Even today I worked WQ7X in Phoenix, Arizona."

Check out Stevie's QRZ.com page for details on his collection of ham radio related maps.

David Moore sent this article about an overlooked piece of the solar dynamo puzzle - a particular form of magnetic instability:

https://www.sciencedaily.com/releases/2019/10/191028104142.htm

The latest video from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/Rm520CkqoLM

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.

Sunspot numbers for October 31 through November 6, 2019 were 0, 11, 13, 0, 0, 0, and 0, with a mean of 3.4. 10.7 cm flux was 71.2, 70.7, 70.7, 69.4, 70.8, 70.4, and 69.3, with a mean of 70.4. Estimated planetary A indices were 7, 4, 2, 2, 4, 5, and 5, with a mean of 4.1. Middle latitude A index was 5, 2, 1, 1, 4, 2, and 4, with a mean of 2.7.
NNNN
/EX

Source: W1AW Bulletin via the ARRL.