SB PROP @ ARL $ARLP036
ARLP036 Propagation de
K7RA
ZCZC AP36
QST de W1AW
Propagation Forecast Bulletin 36 ARLP036
From Tad Cook, K7RA
Seattle, WA September 9,
2017
To all radio amateurs
SB PROP ARL
ARLP036
ARLP036 Propagation de
K7RA
Wow! What a week for solar activity. Although the solar cycle
trend
is down over the past few years and moving toward a solar
minimum
around the year 2020, we will still see notable upticks in
activity,
such as this week's surprising events.
On August 31, http://www.spaceweather.com reported a G-1 Class
geomagnetic storm. Planetary A index was 59. The following
day
Spaceweather.com reported geomagnetic unrest with a planetary
A
index of 19. Planetary A index was 26 on September 2
when
Spaceweather.com reported
sunspot group AR2674 "rapidly growing,
increasing in both area
and sunspot count."
"As the sunspot grows, its magnetic field is becoming
unstable,
posing a threat for M-class solar flares." Planetary A index was
9
on September 3, when Spaceweather.com reported two huge
sunspot
groups facing Earth.
"Behemoth AR2674 has been growing for days, while newcomer
AR2673
has suddenly quadrupled in size, with multiple dark cores
breaching
the surface of the Sun in just the past 24 hours. This movie
from
NASA's Solar Dynamics Observatory shows sunspot genesis in
action:
On September 4, the planetary A index was 18, and
Spaceweather.com
reported: "Huge sunspot AR2673, which materialized with
shocking
speed over the weekend, is seething with activity.
A few days ago in Romania, solar photographer Maximilian
Teodorescu
captured this snapshot of plasma currents surging inside
the
sunspot's magnetic canopy, apparently on the verge of an
explosion":
Note the recent emergence of large sunspot areas:
We also saw the largest solar flare in over a decade launch
Thursday
night.
Predicted solar flux is 115 on September 9, 105 on September 10,
90
on September 11-15, 85 on September 16-17, 88 on September 18, 92
on
September 19-21, then 95, 98, 100 and 105 on September 22-25, 110
on
September 26 through October 2, 105 on October 3-5, then 100,
95,
90, 85 and 80 on October 6-10, 85 on October 11-14, 88 on
October
15, 92 on October 16-18, and 95, 98, 100, 105 and 110 on
October
19-23.
Predicted planetary A index is 30 and 10 on September 9-10, 8
on
September 11-12, then 28, 30, 20, 25 and 12 on September 13-17, 5
on
September 18-19, 8 on September 20, 5 on September 21-22, then 8,
5,
8 and 5 on September
23-26, 20 on September 27-29, then 12, 10, 8
and 5 on September 30
through October 3, 15 on October 4-5, 8 on
October 6, 5 on October 7-9, 25 on October 10-12 then 20 and 10
on
October 13-14, 5 on October 15-16, then 8, 5, 5, 8, 5, 8 and 5
on
October 17-23.
Here is the latest geomagnetic activity forecast for the
period
September 8 to October 4, 2017 from OK1HH:
"Geomagnetic field will be:
Quiet on September 20, 24
Mostly quiet on September 11, 21
Quiet to unsettled September 12, 19, 22, 25, October 2-4
Quiet to active on September 10, 15, 17-18, 23, 26-27, 30, October
1
Active to disturbed on September 8-9, 13-14, 16, 28-29
"Amplifications of the solar wind from coronal holes are expected
on
September 8-10, 13-19, 27-28, October (1,) 2-4
"Remark: - Parenthesis means lower probability of
activity
enhancement and/or lower reliability of prediction.
"F.K. Janda, OK1HH Czech Propagation Interested Group"
Lou, VK5EEE sent this, which I edited:
"Do not believe modern-day short-cut internet-gimmicks such as
this
(he included a reference to an online tool predicting
propagation
titled "HF
Conditions").
"Have a listen to the propagation beacons, tune around the
bands!
Remember there is NO SUCH THING generally speaking as a GLOBAL
HF
one-size-fits-all-situation in spite of the modern trend to
paint
that picture into their
systems. Part of the world is in darkness,
part in light. There are many grey areas. The K index varies
from
location to location. East-West and North-South paths are
affected
differently by events.
"Nor should we rely on advanced real-time programs such as
VOAProp
by G4ILO. While useful, these also give sometimes wildly
false
readings. For example, as I write this, bands including 10m
are
having great propagation to all of America and to Asia, and
perhaps
to other places too, while showing that even with 4kW and a big
high
up Yagi at most S1 signals from a few isolated places north
of
Australia would be possible. NOT. I just need to tune in to 28200
to
hear all the beacons coming in so nice and clear and they
are
running 100W to simple Ground Plane antennas.
"What does the Australian government have to say about
conditions
right now on the SWS website? 'Disturbed!'
"Again we may be tempted to take that at face value. 20-10m has
not
been open much from VK in recent times with very low solar flux
and
no sunspots at times. However right now, 10m is open. 12m is
open,
15, 17 and 20m. Little activity but the beacons are clear, and
Costa
Rica booming in on SSB on 20m even though the local time here
is
high noon with the Sun high in the sky.
"If we look at the regional T index map,
"we see that in Australia and New Zealand conditions are
actually
enhanced.
"If we look at the world map,
"we see that conditions in most of the world are ENHANCED, most
of
the rest is NORMAL and only a few areas in parts of the
Central
Pacific and near to the North Pole (parts of Canada, part
of
Greenland) and northern Siberia are depressed. So why is there
so
much alarm and DEPRESSED shown as a 'one size fits all' on
simple
condensed gimmicks? Well, it is true for those few parts of
the
world. And somewhere the K index is indeed 8, somewhere it is
worse,
somewhere better.
"Bear in mind that while over today and tomorrow there is
a
possibility or even a probability of short wave fade-outs
(not
worldwide but generally on the Sun side of the earth) but the
Solar
Activity being high to very high means that when there is not
a
fadeout conditions are most likely to be enhanced! We should be
SO
HAPPY that solar flux is now well above 100, as that means
HF
openings occur on higher bands more often.
"With the current predicament of those few radio amateurs who
are
not hampered by various distractions, the LOCAL NOISE levels
are
prohibitive on lower
frequencies. When bands above 20m open up, we
should not be scared off by a glance at the RED/POOR prediction
and
miss out on all the easy DX with simple antennas and low noise to
be
had while the higher HF bands are wide open. Let us not forget
the
IBP beacons, and to tune around and call CQ even when
predictions
would encourage you do to otherwise."
Lou makes some excellent points. The various propagation models
used
in the tools for predicting HF success are based on mean
predicted
sunspot numbers for the month, and cannot predict real time
HF
propagation. Lou included this URL: http://30cw.net/ .
On September 7, Mark Lunday, WD4ELG in North Carolina reported
great
propagation to South America on 10 meters using the new FT8
mode.
More about FT8, which is from Joe Taylor, K1JT, can be found
at:
Jon Jones, N0JK in Kansas wrote on September 4:
"10 Meters was back Sunday afternoon August 27 for
intercontinental
DX.
"I had been working the Hawaiian QSO Party on 15 and noted spots
for
Hawaiians on 10. I went to 10... unfortunately did not hear
Hawaii
but logged WP4JW FK68 on 10 SSB at 2307z followed by LU5XP
FF97
Argentina at 2310z. The QSO with WP4JW was probably double hop Es
as
I saw many Es contacts spotted around this time on 10. The
LU
contact may have been Es link to TEP. LU5XP was very loud for
about
15 minutes then vanished abruptly. HK1MW was spotted via Es to
W3,
W7 and W0.
"Stations in Hawaii did work North America on 10 meters August 27,
I
saw Hawaiians spotted by
stations in Florida, Texas, California,
Washington State, Oregon and New Mexico."
If you would like to make a comment or have a tip for our
readers,
email the author at k7ra@arrl.net.
An archive of past propagation bulletins is at
information and tutorials on propagation are at
http://k9la.us/.
Monthly propagation charts between four USA regions and
twelve
overseas locations are at http://arrl.org/propagation.
Instructions for starting or ending email distribution of
ARRL
bulletins are at http://arrl.org/bulletins.
Sunspot numbers for August 31 through September 6, 2017 were 59,
62,
71, 96, 122, 122, and 79, with a mean of 87.3. 10.7 cm flux
was
91.9, 93.4, 100, 120.2,
140, 120.5, and 132.9, with a mean of 114.1.
Estimated planetary A
indices were 31, 19, 26, 9, 18, 12, and 11,
with a mean of 18.
Estimated mid-latitude A indices were 20, 17, 25,
10, 16, 11, and 18, with a
mean of 16.7.
NNNN
/EX
