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SB PROP ARL ARLP002
ARLP002 Propagation de K7RA
All solar activity indicators rose this week, sunspot numbers, solar
flux and geomagnetic indices.
On January 7 the interplanetary magnetic field tipped south, opening
a crack to admit solar wind. This triggered the largest geomagnetic
storm since September 2014. That same day the planetary A index
jumped to 38, pushing the average for the week to 17.7. The previous
seven days (the final seven days of 2014) the average planetary A
index was 13.9.
Average daily sunspot numbers on the first week of January were
108.1, compared to 102.9 in the final seven days of 2014. Likewise,
average daily solar flux increased from 134.9 to 144.7.
The latest prediction has solar flux at 160 on January 9, 165 on
January 10-11, 170 on January 12, 175 on January 13-14, 180 on
January 15, then 170, 165, 160, 155, 145, 140 and 135 January 16-22,
and reaching a minimum at 130 on January 23-27. Solar flux then
rises to a maximum of 175 on February 8-11. The January 15 flux at
180 is the highest predicted solar flux for at least the next 45
days.
Predicted Planetary A index is 15 on January 9, 10 on January 10-12,
8 on January 13, 5 on January 14-20, then 10, 15 and 5 on January
21-23, then 10, 18 and 15 on January 24-26, then 8, 5, 10 and 12 on
January 27-30, 15 on January 31 and February 1, then 10, 8 and 18 on
February 2-4, 10 on February 5-7, 5 on February 8-16, then 10 and 15
on February 17-18.
F.K. Janda, OK1HH predicts quiet to unsettled geomagnetic conditions
January 9-10, quiet on January 11-17, quiet to active January 18,
mostly quiet January 19, active to disturbed January 20, quiet to
active January 21, active to disturbed January 22, quiet January 23,
quiet to active January 24, active to disturbed January 25, quiet to
active January 26, quiet to unsettled January 27, and mostly quiet
January 28.
OK1HH also predicts an increase in solar wind on January 9-11 and
again on January 28.
Mike Morris, WA6ILQ passed along a resource he heard about from Jeff
Kincaid, W6JK. This is part of the new Space Weather Forecast Center
web site, and the page is titled Radio Communication Dashboard:
Each of the three prediction displays is animated. Just hit the
arrow button at the bottom, and the animation begins after a short
delay.
The D Region absorption is important because the D Layer expands in
daylight, and absorbs and attenuates lower frequency radio waves.
This is why 160 meter signals don't propagate for long distances
during daytime.
If 160 meters seems dead after dark, you might check the D Region
absorption to see if absorption is the culprit.
Also on this page is a nice graphic showing aurora probability and
one showing solar X-ray activity.
I ran across this page, which shows a display for Southern
Hemisphere aurora:
It's been some time now since we introduced
http://www.sunspotter.org/#/ via this bulletin, but here it
is
again. We can help classify sunspots by choosing which of two images
is the most complex.
Brad Miskimen, N5LUL of Amarillo, Texas sent a screen shot from
http://www.dxmaps.com/spots/map.php showing a 6 meter
opening on
Friday, January 2 around 2100-2200 UTC. Most of the contacts shown
had their paths crossing at a midpoint near Vicksburg, Mississippi
with an estimated MUF of 61 MHz above EM42 at 2106 UTC.
Scott Bidstrup, TI3/W7RI wrote from Costa Rica: "Propagation on the
upper HF bands has been lackluster at best, with only occasional
days of really good propagation, but the lower HF bands have
benefited noticeably. Daily, on 75 meters, the signals into the
States are very strong in the hours around sunrise and for up to an
hour afterward, and Jay, HP3AK has been having some useful results
for his daily early morning DX hunting in the DX window on 75 at his
gray line. Our morning Central American coffee klatch on 75 meters
has been interrupted occasionally of late by QRM from the States
that often is as strong as the locals. And the local signals just
this morning were as strong as I have ever seen them. I'm hearing
good signals on 60m as well. I really wish we could get back our 60
meters privileges here in Costa Rica - that's a valued and needed
band for us. But the prospects aren't good.
"6 meters is going into its usual Winter funk here, with ever fewer
openings each day. We've been blessed, though, with a lot of short
and erratic openings into the South Pacific, and Andy, YS1AG and
Phil, TI5/N5BEK have been working Bob, ZL1RS and several VK4s at
least once or twice a week. Other than a spectacular but short Es
opening into the States one day last week, and another into northern
Central America, there's been very little Es activity here in
Central America in recent weeks.
"The almost-daily TEP openings from here into South America have
been getting fewer and the signals weaker and being heard for
shorter periods in the evening. Afternoon TEP has all but
disappeared and the evening TEP is getting weaker and less reliable.
That's the usual pattern here for this time of year; we expect
openings to be weak and erratic until March when things should begin
to improve. Time to do some antenna work - getting busy doing other
things ought to stimulate some openings."
If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.
For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,
http://arrl.org/propagation-of-rf-signals. For an
explanation of the
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere. 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 January 1 through 7 were 101, 113, 122, 124, 89,
102, and 106, with a mean of 108.1. 10.7 cm flux was 137.5, 145.8,
148.7, 149.7, 141.9, 141.9, and 147.2, with a mean of 144.7.
Estimated planetary A indices were 7, 12, 15, 21, 18, 13, and 38,
with a mean of 17.7. Estimated mid-latitude A indices were 7, 8, 13,
15, 10, 11, and 23, with a mean of 12.4.
NNNN
/EX
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