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ARRL Propagation Bulletin ARLP008 (2016)

ARLP008 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 8  ARLP008
From Tad Cook, K7RA
Seattle, WA  February 19, 2016
To all radio amateurs 

ARLP008 Propagation de K7RA

Sunspot numbers and solar flux declined over the past week relative
to the previous seven days. Average daily sunspot number went from
86.6 to 56.7, while average daily solar flux slid from 117.4 to
107.8. Geomagnetic indices were up. Average daily planetary A index
went from 9.4 to 17.7, and mid-latitude A index went from 7.4 to

Early in this week was anticipating a CME, but
instead we got a stiff solar wind, causing the planetary A index to
rise to 38 on February 16 and 34 on February 17. This will most
likely subside.

Predicted planetary A index is 20, 12 and 8 on February 19-21, 5 on
February 22-29, then 15, 10, 12 and 8 on March 1-4, then 5, 15, 10
and 8 on March 5-8, then 5 on March 9-10, then 8, 5, 27 and 12 on
March 11-14, and 20, 12, 10 and 8 on March 15-18, and 5 on March

Predicted solar flux is 95 on February 19-20, 100 on February 21-23,
105 on February 24-25, 110 on February 26, 115 on February 27-28,
118 on February 29, 120 on March 1-3, 115 on March 4-5, 110 on March
6-7, 105 on March 8-12, 108 on March 13-14, then 105, 103, 106, 107
and 110 on March 15-19, and 115 on March 20-26.

This week OK1MGW believes geomagnetic field activity (which the A
index expresses as numeric values) quiet to unsettled February
19-20, mostly quiet February 21, quiet on February 22-25, mostly
quiet February 26, quiet to unsettled February 27-28, quiet to
active February 29 to March 1, quiet to unsettled March 2, quiet to
active March 3, quiet to unsettled March 4, quiet to active again on
March 5-6, quiet to unsettled March 7-8, quiet to active March 9-10,
quiet to unsettled March 11-12, quiet to active March 13, active to
disturbed March 14-15, and quiet to active March 16.

Jeff, N8II in Shepherdstown, West Virginia (FM19cj) wrote on
February 12, "FYI today SFI (solar flux) down 1, K index 3 at 1500Z.
10 meters was very slow to open to Europe today, but finally around
1520Z, I started working fairly loud
Germans/Netherlands/Belgium/Italy/Switzerland, some very loud
signals and a few weak ones. I worked one summit activator in DL who
was over S9, but think he was using a Yagi and was not QRP. Still
open well at 1630Z when I went QRT. 12 meters was open much earlier,
but a bit spotty in coverage.

"Supposed to get howling winds and below zero/single digit wind
chills starting overnight thru Sunday AM, Brrrrrr!

"We had wind chill around 5 deg F almost all day yesterday, winds
15-30 MPH."

A fascinating article appeared in Sky and Telescope on Valentine's
Day, about how sunspots are counted:


The third paragraph mentions "all sorts of models" which use sunspot
records to predict "climate, orbit of satellites, and stability of
power grids." I would caution though that back in the 1970s and
earlier, climate scientists tried to correlate solar activity with
climate, and found a weak correlation, which only worked prior to
the industrial age.

Regarding the stability of power grids, this probably refers to
blasts of CME energy and solar wind, which you may have noticed seem
to peak after solar maximum. We are seeing this right now, and I
have noticed it in previous sunspot cycles.

NN4X sent this, concerning the solar dynamic observatory:

Here is an article claiming another solar max in 2023, nine years
after the recent solar maximum. But why do they use my first name at
the start of paragraph two? Is TAD an acronym? Or maybe this is from
another subculture I am not familiar with, where the expression "Tad
Dramatic" is widely understood? I wish I knew, but I must admit,
rather like that expression.

This paragraph is interesting:

"This solar cycle decline helps to disprove solar hypotheses stating
that the witnessed temperature rise on Earth would be caused to
extra solar activity, if solar played any significant role over the
last couple of decades, it should have manifested a net cooling

But we don't cover climate in this bulletin.

Dr. Jon K. Jones, MD, N0JK of Lawrence, Kansas wrote on February 18,
concerning 6 meters:

"A geomagnetic storm is in progress February 16-19 with the 24 hour
K index on February 18 peaking at 6.

"Some aurora was worked on 6 meters from Minnesota February 17:

"K0SIX, 2329Z 50125 EN34 Au EN35 by WB4SIA K0SIX, 2329Z 50125 EN35
EN44 by K9MU

"The following morning, February 18, strong sporadic-E on 6 meters
from Florida to Illinois, Indiana, Michigan and Ohio. The 1 watt
WA3TTS/b was copied 559 on 6 meters by K8XX in EL88 Florida.

"Some spots, all from February 18:

"WA3TTS/B, 1416Z  50068 EL90  1 W ERP heard 55 in EL88 by K8XX

"K9OIM, 1402Z  50125 EL98 by KC8UDV

"KJ4E, 1358Z 50125 59 +20 by KC8UDV

"K8MMM/B, 1355Z 50010 EL98IT<>EN91IG 59+, by KJ4E

"W3PIE/B, 1339Z 50062 EL98IT<>FM09MM by KJ4E

"WA8FTA, 1335Z 50098 EL98IT<>EN52MK by KJ4E

"KJ4E, 1326Z 50099 EN62AX<>EL9 by WA9CAT

"WA9CAT, 1325Z 50099 EL98IT EN62AX TU QSO by KJ4E"

The DX maps show some of the paths toward the end of the opening.
The Es may have been associated with the geomagnetic activity.

Upcoming (today!) is the CW weekend of the ARRL DX Contest.
According to the rules, the objective is "To encourage W/VE stations
to expand knowledge of DX propagation on the HF and MF bands,
improve operating skills, and improve station capability by creating
a competition in which DX stations may only contact W/VE stations."

It begins this evening (Friday, North America time) at 0000 UTC
Saturday and ends 2359 UTC Sunday.

See here for more details and rules:

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 February 11 through 17 were 68, 74, 46, 52, 48,
49, and 60, with a mean of 56.7. 10.7 cm flux was 112.8, 112.2,
110.3, 108, 107.3, 104, and 99.9, with a mean of 107.8. Estimated
planetary A indices were 11, 13, 7, 10, 11, 38, and 34, with a mean
of 17.7. Estimated mid-latitude A indices were 8, 11, 7, 6, 10, 25,
and 21, with a mean of 12.6.