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ARRL Propagation Bulletin ARLP046 (2015)

ARLP046 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 46  ARLP046
From Tad Cook, K7RA
Seattle, WA  November 13, 2015
To all radio amateurs 

ARLP046 Propagation de K7RA

At 2240 UTC on November 11, the Australian Space Forecast Center
issued a geomagnetic disturbance warning: "Combined CME and coronal
hole effects are expected to become geo-effective on 12-Nov,
resulting in active to minor storm conditions." They predicted quiet
to minor storm conditions on November 12, and unsettled to active
conditions on November 13.

A few days ago the Washington Post ran this story about a possible
geomagnetic storm:

The Washington Post also shared this video from NASA of the recent
solar flare eruption:

David Moore sent this link last week about a geomagnetic disturbance
on November 4 which made planes disappear from air traffic control
screens in Sweden:

The College A index (measured near 64.9 deg N. latitude, near
Fairbanks, Alaska) on that date was a very high 55. Stockholm is
around 59.3 deg N. latitude. It is generally true that geomagnetic
disturbances are more intense at higher latitudes.

Over the past week (November 5-11, our reporting week for data
covers Thursday through Wednesday) compared to the previous seven
days average daily sunspot number declined from 90.3 to 72.3, and
average daily solar flux went from 118.3 to 109.4.

Geomagnetic activity increased, with average daily planetary A index
going from 14.7 to 25 and mid-latitude A index from 12 to 19.

The latest forecast from USAF/NOAA has solar flux at 107 on November
13, 113 on November 14-15, 110 and 107 on November 16-17, 105 on
November 18-22, 110 on November 23-25, and 115 on November 26-27.
Solar flux peaks at 120 on November 28-30 before dropping to a low
of 100 on December 14-15. Solar flux is expected to rise to 120
again about ten days later.

Predicted planetary A index is 12, 20 and 12 on November 13-15, then
8 on November 16-17, 5 on November 18-25, 8 on November 26, 5 on
November 27, 8 on November 28-29, 25 on November 30 and December 1,
then 15, 8, 5, 12, 25, 18 and 12 on December 2-8 and 8 on December

Petr Kolman, OK1MGW of the Czech Propagation Interest Group expects
geomagnetic conditions to be quiet to active on November 13-14,
mostly quiet November 15-21, quiet on November 22-23, quiet to
unsettled November 24-25, mostly quiet November 26-29, active to
disturbed November 30 and December 1, quiet to active December 2,
quiet to unsettled December 3-4, quiet to active December 5, active
to disturbed December 6, quiet to active December 7, and quiet to
unsettled December 8-9.

He expects increases in solar wind on November 13-14, November 30
through December 2, and December 5-7.

I have automated searches running constantly for appearances of the
word "sunspot" on the web and in news stories, but not all the
results refer to actual solar events. For instance (this was new to
me) in Great Britain it seems that sunspot is also a word for any
popular winter travel destination at lower latitudes. Another recent
search revealed Sunspot is the name of one of the "My Little Pony"
figures, from an online collector's forum. But the strangest was a
link to an EDM (electronic dance music) mp3 file titled (I am not
making this up), "Powerful X-Class Solar Flare Erupts from Active

Sometimes I DJ EDM at local dances. Perhaps I should give it a

Included with December 2015 QST is a reproduction of the first issue
of QST magazine, which was published 100 years ago in December 1915.

On page three is a passage related to propagation that applies now,
100 years later:

"December Radio Relay Bulletin Season Opening.  The cool weather has
arrived, static is getting better every night, and the owners of
relay stations are returning to their instruments."

Also included is a list of all known amateur radio stations in North
America. In 1915 they operated CW only using spark gap transmitters,
and they made up their own callsigns.  I was pleased to see of the
three amateurs in Washington state, here in Seattle was 7NG (later
W7OE), Howard S. Pyle, 3376 York Road, Seattle. I believe he was
born in 1896, so he would probably have been 19 years old at the
time. Years later he was an author of many popular books and
magazine articles on amateur radio.

In that first issue is a very serious sounding discussion of how to
set up networks to pass messages across the country. In the text
they mentioned "Reliability and Certainty" and "Reliability and
Celerity." I had never heard of celerity, but it is a real word,
meaning rapidity of motion or action and swiftness of movement.

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 the
numbers used in this bulletin, see An archive of past
propagation bulletins is at More good
information and tutorials on propagation are at

My own archives of the NOAA/USAF daily 45 day forecast for solar
flux and planetary A index are in downloadable spreadsheet format at and .

Click on "Download this file" to download the archive, and ignore
the security warning about file format. Pop-up blockers may suppress
the download.

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 November 5 through 11 were 75, 86, 79, 70, 67,
65, and 64, with a mean of 72.3. 10.7 cm flux was 109.9, 115.2, 115,
107.7, 107.6, 105.4, and 105, with a mean of 109.4. Estimated
planetary A indices were 16, 15, 43, 14, 26, 38, and 23, with a mean
of 25. Estimated mid-latitude A indices were 11, 11, 29, 11, 22, 32,
and 17, with a mean of 19.


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