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ARRL Propagation Bulletin ARLP015 (2019)

ARLP015 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 15  ARLP015
From Tad Cook, K7RA
Seattle, WA  April 12, 2019
To all radio amateurs 

ARLP015 Propagation de K7RA

Similar to the last reporting week in Propagation Forecast Bulletin
ARLP014, the first three days (Thursday through Saturday) had no
visible sunspots, but sunspots returned on Sunday through Thursday.
Average daily sunspot number declined from 9.4 to 6.9, but average
daily solar flux rose from 69.5 to 75.4.

Geomagnetic indicators were slightly more active, with average daily
planetary A index increasing from 8.4 to 10.6, and average middle
latitude A index from 7.3 to 9.

Predicted solar flux for the next 45 days is 78 on April 12-17, 76
and 74 on April 18-19, 70 on April 20-22, 69 on April 23, 70 on
April 24-28, 71 on April 29 through May 1, 72 on May 2-3, 77 on May
4-6, 74 on May 7-16, 70 on May 17-19, then 69, 68, 69 and 69 on May
20-23, 70 on May 24-25 and 71 on May 26.

Predicted planetary A index is 12 on April 12-13, 5 on April 14-23,
then 10, 8, 5, 10, 8, and 5 on April 24-29, 10 on April 30 through
May 2, 7 on May 3, 5 on May 4-20, then 10, 8, 5, 10, 8 and 5 on May

On April 7 sunspot group 2738 appeared. Currently (Thursday, April
11) you can see it as the bright spot on the STEREO image at:

Of course, the bright spot will move from left to right over time,
until it disappears off the right side.

Geomagnetic activity forecast for the period April 12 to May 8, 2019
from F.K. Janda, OK1HH.

"Geomagnetic field will be:
Quiet on April 14, 17-19 
Quiet to unsettled on April 16, 20-23, 26, 29, May 2-4
Quiet to active on April (15,) 28, May 1 
Unsettled to active on April (24-25, 27,) 30, May 5-8
Active to disturbed April (12-13)

"Solar wind will intensify on April 12-13, 15-16, (19-23,) 24-25,
(26-30,) May (1,) 2-3, (5, 8)

"Parenthesis means lower probability of activity enhancement."

Thanks to David Moore for this article:

The Solar Cycle 25 prediction panel met last week in Boulder, and
they see an end to declining solar cycles, and they do not predict
another grand minimum similar to the terrifying (to hams) Maunder

The Washington Post had an interesting take on the prediction,
indicating the next solar cycle could be stronger:

Here is a tweet from Scott McIntosh, Director of the National Center
for Atmospheric Research's High Altitude Observatory offering his
opinion that Solar Cycle 25 will be stronger than Solar Cycle 24:

Steve Ford, WB8IMY sent this article on accurate predictions of
space weather. It has a nice video on the perils of space weather:

Mike Schaffer, KA3JAW of Easton, Pennsylvania sent this report:

"Tuesday evening, April 9, 2135 UTC (5:35 PM EDT local) I was
monitoring the 11-meter Citizen Band (27 MHz) and telltale signs of
sporadic-E, swooshing, fading in and out of signals on channel 19,
which is active with interstate truckers was causing interference to
local operators.

"Sporadic-E was emerging from the state of Florida, around Miami.

"During the 2200 UTC (6:00 PM EDT local) central cities of
Melbourne, Orlando, Ocala, and Gainesville were heard. At 2310 UTC
(7:10 PM EDT local) the Es plasma cloud was shifting westerly over
Tampa. Ten minutes later, Es had vanished. Most likely the cloud
(not the internet one) had moved over the Gulf of Mexico where there
are no truckers.

"The most distant station, Miami, was 1,070 air miles from Easton,
Pennsylvania. The MUF made it up into the 6 meter band, but not high
enough for the low-VHF TV or the FM broadcast bands. The reported
geomagnetic field was at quiet to unsettled levels with a 10.7 cm
flux at 79. The MUF had intensified with durations becoming longer
compared to last week."

Jeff, N8II in West Virginia sent this report:

"Here we go again; the SFI has been near 80 for 3-4 days

"Unfortunately, 15M has not come to life except for stations to the
south. I keep seeing spots for C5DL in the Gambia on 15M and hear
little or no signal. 17M does come to life a bit when the flux hits
the upper 70s.

"Conditions were not good to Missouri during their QSO Party from
here. 20 was marginal then closed around 1900Z Saturday and signals
seemed weaker than expected on 40 during the day. On top of that,
storms in the Gulf Coast area caused QRN even on 20M and I was
unable to work any Mississippi QSO Party stations on 75 phone during
their round table net due to high noise on their end.

"The good news is that 30M down to 80M have been pretty good many
nights. I would say the average signal levels on 80 far exceed the
levels on December and January with March probably being the best
month, but signals from the big guns in EU are still S9+ many

"I managed to work C5DL on 160 on the April 11 at 0044Z; they were
Q5 copy about 90% of the time here with low noise levels.  They have
also been logged on 80, 40, 30, and 20M, no luck on 17M so far.

"Most days several European Russians are loud on 20M and they have
several special prefixes running as well as many AM70 and other AM
prefixes from Spain to celebrate the 80th anniversary of URE.

"On April 11, signals were booming from Spain at 2100-2200Z on 20
meters; signals have been fairly weak around 1300-1600Z from Spain,
but I suspect most AM70 stations were beaming towards Eastern EU.

"On April 5, Turkey and two booming Bulgarians were worked on 20M in
the 2000Z hour.

"Mikhail, VE7ACN has been touring islands in Nova Scotia and New
Brunswick and generating large EU pile ups on 40, 20, and even one
time I heard the pile up on 17M. The skip zones are so long, that he
skipped over me on 20M several days until the solar flux improved. I
can hear SE Asia stations some days on 20, but working through the
EU pile ups is very difficult.

"There is still a decent long path opening to Australia on 30 and
20M around 2100Z. That path was very good during our Winter.

"Today, April 11 was fun with some booming signals from the south on
12 and 10 meters.  Columbia, two from Chile, and St. Lucia, were
logged on 10 SSB around 2050Z and Teddy, VP2ETE on Anguilla was loud
on 12M SSB at 2115Z. Several of these stations were S9 or better
here and they were only using dipoles."

Dr. Tamitha Skov, WX6SWW issued this report on April 10:

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 April 4 through 10, 2019 were 0, 0, 0, 11, 12,
12, and 13, with a mean of 6.9. 10.7 cm flux was 70.3, 71.7, 73.6,
76.5, 78.6, 79, and 78.1, with a mean of 75.4. Estimated planetary A
indices were 10, 14, 7, 5, 13, 11, and 14, with a mean of 10.6.
Middle latitude A index was 8, 10, 7, 5, 12, 11, and 10, with a mean
of 9.


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