Register Account

Login Help

ARRL Propagation Bulletin ARLP045 (2019)

ARLP045 Propagation de K7RA

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

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. 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:

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:

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 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 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:

The latest video from Dr. Tamitha Skov, WX6SWW:

If you would like to make a comment or have a tip for our readers,
email the author at, .

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at, For an explanation of
numbers used in this bulletin, see

An archive of past propagation bulletins is at More good
information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve
overseas locations are at

Instructions for starting or ending email distribution of ARRL
bulletins are at

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.


Instragram     Facebook     Twitter     YouTube     LinkedIn