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ARRL Propagation Bulletin ARLP008 (2018)

ARLP008 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 8  ARLP008
From Tad Cook, K7RA
Seattle, WA  February 23, 2018
To all radio amateurs 

ARLP008 Propagation de K7RA

Average daily sunspot number dropped from 24 during the previous
seven days, to 5.6 in the current reporting week, February 15-21.
That average is so low because no sunspots have been seen since
February 17, and no new sunspot regions were observed since February
4. Average daily solar flux dropped to 70.1 in the current period
from 77.4 in the previous week.

Based on the latest 45-day prediction for solar flux, I expect
sunspots to re-appear by March 2 or 3, when solar flux is expected
to increase suddenly.

Predicted solar flux is 68 on February 23 to March 1, 69 on March 2,
76 on March 3-12, 74 on March 13-14, 72 on March 15, 70 on March
16-25, 72 and 74 on March 26-27, and 76 on March 28 through April 8.

Predicted planetary A index is 8 on February 23-25, then 12, 16 and
8 on February 26-28, 5 on March 1-3, 8 on March 4, 5 on March 5-13,
then 10, 8, 12, 16, 14 and 12 on March 14-19, 8 on March 20-22, 5 on
March 23-30, 8 on March 31 and 5 on April 1-8.

Greg Andracke, TI7/W2BEE wrote from Costa Rica, where he is

"Now on the air with a 124.5 ft. sloper. Working CW ONLY when not in
the pool! In Playa Garza, Guanacaste, Costa Rica until about March
15. If anyone needs a CW contact, email me at, -- I'm
not running pileups, just chatting with folks. Made only a few
contacts during ARRL DX Test because I couldn't get antenna
installed until about 3 hours before the test was over.

"Worked VK3IO on 30M with my modest setup, K2/100 and sloper into
9:1 UNUN."

Greg has a fascinating career filming documentaries. See .

A new space weather video from Dr. Tamitha Skov from last week: .

Paul Gray, N0JAA of Melbourne, Florida wrote:

"Late Winter/early Spring is generally the time of year in Florida
when we typically experience tropospheric ducting.  2018 is no
exception.  This year I have experienced a good amount of ducting on
2 meters. I don't have sideband capability on that band currently,
so my experience is limited to FM repeaters and simplex.  For the
VHF bands of 2 meters and 1.25 meters, and the UHF 70 centimeter
band (and perhaps higher), tropospheric ducting in Florida occurs
mostly in the late evening and overnight hours.  The 6 meter band,
at least in my personal experience, does not appear to be
significantly affected by tropospheric ducting.

"Over the last week or so, I have been receiving a distant repeater
on my club's repeater frequency of 146.610 MHz (W4MLB) in Melbourne.
I have been able to receive and, after a fashion carry on QSOs with,
several stations on the K4GSO repeater.  The trick is to let each
repeater drop before responding, but it can be done.  Considering
that 2 meters is basically line of sight +/- a few miles beyond the
horizon, and the distance between Melbourne and Ocala is
approximately 150 miles, this is a good feat, especially with a
5-watt HT and a 1/2-wave mag mount antenna!  I would consider this
DX on 2 meters.

"This is my recent experience with propagation.  It isn't
ionospheric propagation, but tropospheric ducting will produce
propagation on a more local scale which is useful in and of itself."

Geomagnetic activity forecast for the period February 23 to March
20, 2018 by F.K. Janda, OK1HH.

"Geomagnetic field will be:
Quiet on February 25-26, March 1, 6, 10, 12-13, 19-20,
Mostly quiet on February 27, March 2, 7, 11,
Quiet to unsettled on February 23-24, March 3, 5, 8, 15-16,
Quiet to active on February 28, March 4, 9, 17-18,
Active to disturbed on March 14.

"Amplifications of the solar wind from coronal holes cannot be
predicted for the period until March 10, but I do not expect any
significant upsurge. Then solar wind will intensify on March 18-20.

"Remark: - Parenthesis means lower probability of activity enhancement.  
- With regard to ongoing changes, current forecasts
remain less reliable, especially in the first half of March."

Tomas Hood, NW7US who edits the Propagation column in CQ Magazine
was interviewed by Eric Guth, 4Z1UG for Eric's podcast "QSO Today." .

If you change the end of the above URL from nw7us to k7ra, you'll
hear my interview from about two years ago.

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 February 15-21, 2018 were 15, 12, 12, 0, 0, 0,
and 0, with a mean of 5.6. 10.7 cm flux was 72.5, 71.5, 69, 70.3,
69.1, 70.5, and 67.6, with a mean of 70.1. Estimated planetary A
indices were 11, 7, 12, 14, 17, 5, and 4, with a mean of 10.
Estimated mid-latitude A indices were 6, 7, 10, 14, 11, 3, and 3,
with a mean of 7.7.


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