ARRL Propagation Bulletin ARLP050 (2018)

Accessed on 15 December 2018, 1540 UTC, Post 804.


Author:  Tad Cook (K7RA).

Please scroll down to read the complete propagation forecast from Tad Cook (K7RA) and his volunteer staff of observers.

ARLP050 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 50  ARLP050
From Tad Cook, K7RA
Seattle, WA  December 14, 2018
To all radio amateurs 

ARLP050 Propagation de K7RA

Our recent reporting week (December 6-12) had sunspots on five of
the seven days, with an average daily sunspot number of 9.7, up from
2.3 in the previous seven days. Average daily solar flux rose from
68.9 to 70.7. Geomagnetic indices were moderate, with average daily
planetary A index rising from 7 to 8, and mid-latitude A index
increasing from 4.9 to 6.4.

Predicted solar flux over the next 45 days is 70 on December 14-19,
68 on December 20-22, 70 on December 23 to January 4, 68 on January
5-18, and 70 on January 19-27.

Predicted planetary A index is 5 on December 14-15, 8 on December
16-17, 5 on December 18-27, then 8, 12, 10 and 8 on December 28-31,
5 on January 1-2, 10 on January 3-4, 8 on January 5-6, 5 on January
7, 8 on January 8-9, 5 on January 10-12, 8 on January 13-14, 5 on
January 15-23, then 8, 12, 10 and 8 on January 24-27.

Geomagnetic activity forecast for the period December 14, 2018 to
January 9, 2019 from F.K. Janda, OK1HH.

"Geomagnetic field will be:
Quiet on December 14-15, 18-23,
Quiet to unsettled on December 16, 24-27, January 9
Quiet to active on December 17, 28, January 1-2
Unsettled to active on December 29, (30-31), January 3-8
No Active or disturbed days predicted.

"Solar wind will intensify on November 30 and on December (15-18,
24-27,) 28-31, January 1, (3-4,) 5-7, (8)

"Parenthesis means lower probability of activity enhancement."

On December 11 N0JK reported on the ARRL 10 Meter Contest from
Kansas, "Much better conditions in the ARRL 10 meter contest this
year than last.

"On Saturday afternoon, had E-skip on 10 to W4 and W5, which allowed
links on to F2/TEP propagation to South America. Running just 5
watts, I logged CE, CX, LU and PY stations via Es link. Double hop
Es to HK, P4 and PJ2. Single hop Es to W4 and W5.

"Sunday the band conditions not nearly as good, but see the
northeast states had strong Es to Florida. This in turn allowed them
to link on to South America. See DX maps, which clearly show this
classic setup. Also strong single hop Es along the West Coast.

"Had some weak Es in Kansas, heard CO8RH but he faded out while I
was fiddling with my hand key. I was able to work 9Z4Y on 10M CW."

Another report on last weekend's 10 meter contest was from Jeff
Hartley, N8II in West Virginia:

"Conditions last weekend were much better than last year in the ARRL
10 meter contest. My first QSO beyond local range was VE2FK in
Quebec at 0045Z (Friday local time) followed by WI/MN and SD
starting 10 minutes later. Then ME, Nova Scotia, and New Brunswick
came through followed by the Gulf coast from TX around to FL all on
sporadic-E (Es). At 0220Z there was a brief double hop Es opening to
CO and NE. Around 0300Z FL came back in and even at 0420Z FL
stations were still good copy but fading.

"Saturday started slow until 1416Z when I found W0WP in IA followed
by one WI on scatter. The next opening was 1540Z when CE7VPQ in
Chile was found on SSB (first F2 QSO) followed by Argentina and
Brazil. Then at 1622Z Es started from MN, WI, IA, then IL, MO, NE,
then AR, MO, KY, TN, and KS.

"At 1740Z, OK, TX, and AR were loud and soon after XE2HQI in
northern Mexico was found. Southern SA was back at 1800Z along with
some F2 backscatter QSOs into the W8/9 call areas. Then, NM was
found at 1826Z on either double hop Es or F2 and K6AM in CA 1831Z.

"For the next hour, a huge number of stations were worked mostly in
AZ, CA, NM, and NV as well as backscatter into Ontario and W1/2
along with several XEs in Mexican states mostly on F2. A big
surprise was being called by VK2BJ in New South Wales, Australia on
CW at 1851Z, very early, best DX of contest!

"The band stayed open to SA and XE until about 2035Z with last QSOs
into Bonaire and Columbia. Another amazing QSO was ZL6YOTA (Youths
On The Air) in New Zealand at 0200Z probably via double hop Es into
F2 on the other end.

"Sunday conditions were much poorer after a very good sporadic-E
opening to FL until about 1420Z. Mostly marginal SA openings in and
out along with some scatter (meteor and ionospheric) sums up what
was available. W0AIH in WI was nearly constantly readable on
ionospheric scatter and a few other Midwest stations were worked
scatter too. Starting 1518Z, Aruba, Curacao, and Venezuela were all
added as new countries in a spotlight F2 opening.

"Conditions were good enough to allow 63 QSOs with FL, 24 with AZ, 9
with XE, and 23 with CA. 69 locals in MD were logged."

The latest from Dr. Tamitha Skov, WX6SWW:

"Whirlwind of a Season

"Dear Tad,

It's hard to believe I haven't written since Thanksgiving. Many of
you already know I have had a challenging go of it over the last six
weeks or so. Between the southern California wildfires coming so
close to my home and now two members of my immediate family having
emergency medical procedures, it's been a whirlwind of a season! I
cannot express the depth of my appreciation for all the notes of
comfort and encouragement I have received from you recently. Your
kind words and patience through it all have helped me stay positive
and hopeful during this crazy ride.

"As for your recent emails, I am finally able to begin writing back.
So, if you are expecting an answer from me, it will be coming in the
next few days! Also, to play catch up, I recently did a live
mini-course on Space Weather indices. This is a really complicated
topic that you can't find well explained anywhere. It has turned out
to be one of my most popular courses and I've gotten amazing
feedback about how helpful it has been to everyone. So, just in case
you missed it but want to see it, I am including a link here:

"As for the forecast this week, we have been enjoying an extended
period of moderately fast solar wind. The weak storming kept us at
unsettled conditions, which brought aurora to high latitudes and
improved GPS at low latitudes over the past 10 days. However, the
Space Weather will slowly quiet down as we approach week's end.
Thankfully, not all is going quiet. Three new active regions are now
facing Earth and are boosting the solar flux. This means amateur and
shortwave radio should improve, especially on Earth's day side. With
any luck, these regions will continue to brighten the Sun's face
over the next week. So, despite conditions quieting down, between
the recent aurora and now the elevated flux, it looks like the Sun
is already beginning to spread the holiday cheer!

"Cheers, Tamitha

Latest forecast from Dr. Skov:

In last week's Propagation Forecast Bulletin ARLP049, I noted a new
updated forecast for smoothed sunspot numbers and solar flux from
NOAA on pages 10-11 at:

These seemed to show predicted activity headed for extremely low
numbers out to the year 2022, with most of that year having no
sunspots. But I believe these numbers are suspect, because if you
look at solar flux numbers they go to some low values that have not
been seen ever before.

These smoothed numbers are a moving average over a whole year. It
shows the smoothed solar flux going down to 59, which has not been
seen ever before. I inspected daily solar flux during the last
minimum, and decided to look at the six months on both sides of
7/17/2008. If I average the flux values for a year centered on that
date, I get a value of 68.68. Around that time in 2008-2009 there
were extended periods with no sunspots.

So, I suspect there are errors in these predictions, and will wait
for NOAA to clarify this forecast and probably correct them.

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

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bulletins are at

Sunspot numbers for December 6 through 12, 2018 were 17, 16, 12, 12,
0, 11, and 0, with a mean of 9.7. 10.7 cm flux was 69.7, 70.1, 70.5,
71.6, 71, 71, and 70.8, with a mean of 70.7. Estimated planetary A
indices were 5, 10, 10, 9, 11, 7, and 4, with a mean of 8. Estimated
mid-latitude A indices were 3, 8, 10, 6, 8, 7, and 3, with a mean of