02/05/2016
Over the recent reporting week (January 28 through February 3) both sunspot and
solar flux averages were down a negligible amount, and geomagnetic numbers were
down substantially, compared to the previous seven days.
Average daily sunspot numbers declined from 57.3 to 50.6, while average daily
solar flux values went from 106 to 105.4. Average daily planetary A index
softened from 11.6 to 7.3, while the mid-latitude A index (measured in
Fredericksburg, Virginia) went from 7.6 to 5.6.
The latest predicted solar flux is 125 on February 5-6, 120 on February 7, 115
on February 8, 110 on February 9-11, 105 on February 12-20, 100 on February 21
through March 2, 95 on March 3, 90 on March 4-5, 95 on March 6-8 and 105 on
March 9-18.
Predicted mid-latitude A index is 6 on February 5, 5 on February 6, then 8, 18,
and 12 on February 7-9, 6 on February 10-11, 5 on February 12-16, then 10, 15,
12 and 10 on February 17-20, 5 on February 21-27, then 8 on February 28-29, 15
and 8 on March 1-2, 5 on March 3-5, then 12, 10 and 8 on March 6-8 and 5 on
March 9-15.
OK1MGW predicts geomagnetic activity will be mostly quiet February 5-6, quiet
to active February 7-8, quiet to unsettled February 9-10, mostly quiet February
11, quiet February 12-14, quiet to unsettled February 15, quiet to active
February 16-18, quiet to unsettled February 19-20, mostly quiet February 21,
quiet February 22-25, mostly quiet February 26-28, quiet to active February 29
through March 1, and quiet to unsettled March 2.
During the March 16-18 period when he predicts quiet to active conditions, we
may see active to disturbed conditions Match 16-17, although he is uncertain
about this.
He says we may see increased solar wind on February 7-8, 16-18 and February 29
through March 1.
Skip Burroughs, KS5KIP, of Capitan, New Mexico sent a query about how to apply
some of the data from this bulletin to get a feel for what propagation will be
like.
One way to do this is to use a propagation prediction program and do
predictions based on your location for various locations and frequencies of
interest.
One free program for doing this is W6ELprop, which you can download from
http://brucerichards.com/army/w6elprop.htm[1]. K9LA has some more info on
running the program here: http://k9la.us/Propagation_101_23Sep07.pdf[2] and
here: http://k9la.us/W6ELProp_tutorial.pdf[3]
Basically what we want to see in the weekly numbers are rising solar flux and
sunspot numbers and lower A index, at least ideally.
You could take the average daily sunspot number from the bottom of this
bulletin (50.6 in this bulletin) and use that in the program. If we run that
for Capitan, New Mexico for this Sunday toward Japan, we see that 40 meters
should be good 0600-1500 UTC, with best signals around 0900-1400 UTC. 30 meters
seems good 0700-1430 UTC, 20 meters looks rather weak, but possibilities
include 2100-0300 UTC and another possible opening at 1500-1600 UTC. 17 meters
looks much stronger 2130-0200 UTC, and 15 meters 2200-0030 UTC. 12 meters looks
promising 2230-2330 UTC.
From Capitan to Chicago, 15 meters looks possible 1730-2000 UTC, 17 meters
looks better 1630-2200 UTC, 20 meters 1500-0000 UTC and 30 meters 1330-0130
UTC. 40 meters looks excellent any time of the day or night, with best signals
0100-1300 UTC and open, but about 13 db lower signals but still open 1730-1930
UTC. 75 meters looks best 0130-1230 UTC.
Vary the date using the same numbers, and you will see seasonal effects on
propagation. For instance, the path to Japan on March 22 opens on 17 meters an
hour earlier and closes over 2 hours later.
Next week I should have an evaluation copy of ACE-HF, another propagation tool
and I hope to review it.
Now that January is over, we can look at our 3-month moving averages of sunspot
numbers t check the progression of this solar cycle. This gives us the latest
number, centered on December 2015.
We saw the peak centered on February and March 2014, when the three month
moving averages were 146.4 and 148.2. The highest single monthly average at the
peak of the solar cycle was February 2014, at 174.6.
The latest 3-month average was 55.4 centered on December 2015, which included
all of the daily sunspot numbers from November 1, 2015 through January 31 2016.
The 3-month moving averages of sunspot numbers centered on January through
December 2015 were 98.2, 78.1, 68.2, 72.4, 77.7, 76.3, 69.1, 67.5, 64.5, 64.6,
58.5 and 55.4. With this moving average you can see a smooth, steady decline in
cycle 24.
For more information concerning radio propagation, see the ARRL Technical
Information Service at http://arrl.org/propagation-of-rf-signals[4]. For an
explanation of the numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere[5]. An archive of past
propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation[6]. More good information
and tutorials on propagation are at http://k9la.us/[7] .
My own archives of the NOAA/USAF daily 45 day forecast for solar flux and
planetary A index are in downloadable spreadsheet format at
http://bit.ly/1VOqf9B[8] and http://bit.ly/1DcpaC5 [9].
Click on "Download this file" to download the archive, and ignore the security
warning about file format. Pop-up blockers may suppress the download.
Monthly propagation charts between four USA regions and twelve overseas
locations are at http://arrl.org/propagation [10].
Instructions for starting or ending email distribution of ARRL bulletins are at
http://arrl.org/bulletins[11] .
Sunspot numbers for January 28 through February 3 were 64, 49, 30, 39, 42, 52,
and 78, with a mean of 50.6. 10.7 cm flux was 109.9, 106.9, 105.1, 101.2,
100.2, 102.1, and 112.1, with a mean of 105.4. Estimated planetary A indices
were 6, 3, 3, 10, 9, 6, and 14, with a mean of 7.3. Estimated mid-latitude A
indices were 5, 3, 3, 8, 6, 4, and 10, with a mean of 5.6.
[1] http://brucerichards.com/army/w6elprop.htm
[2] http://k9la.us/Propagation_101_23Sep07.pdf
[3] http://k9la.us/W6ELProp_tutorial.pdf
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://arrl.org/w1aw-bulletins-archive-propagation
[7] http://k9la.us/
[8] http://bit.ly/1VOqf9B
[9] http://bit.ly/1DcpaC5
[10] http://arrl.org/propagation
[11] http://arrl.org/bulletins
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