http://www.arrl.org/files/file/Technology/pdf/119962.pdf)
From Tad Cook, K7RA
Seattle, WA February 15, 2013
To all radio amateurs
Propagation de K7RA
Low levels of solar activity continue, the same as the past few
weeks. Sunspot numbers remain remarkably consistent, with average
daily numbers for the four reporting weeks since January 17 at 56.4,
55.7, 50.7 and finally 51.3 for the past week. As you can see,
average daily sunspot numbers rose less than a point from the
previous week to the past week. Average daily solar flux receded
2.4 points to 104. Geomagnetic conditions remain calm.
The latest prediction for solar flux shows values of 100 for
February 15-16, 105 on February 17-19, 100 on February 20-22, 115 on
February 23-24, 110 and 105 on February 25-26, 100 on February 27
through March 3, 95 on March 4-9,115 on March 10 and 120 on March
11-13.
The predicted planetary A index is 5 on February 15-20, 9 on
February 21-22, 8 on February 23, 5 on February 24-28, then 10 and 8
on March 1-2, and 5 on March 3-17.
Every week F.K. Janda, OK1HH gives us his thoughts on geomagnetic
conditions over the next few weeks. Generally for HF propagation,
particularly for the higher bands (10-20 meters) we would like to
see very little geomagnetic activity, but with as many sunspots and
as much solar flux as possible. We have seen a lot of quiet
geomagnetic conditions over the past few years, but not much in the
way of sunspots or high solar flux values.
OK1HH suggests the geomagnetic field will be quiet to unsettled on
February 15-16, quiet on February 17-21, quiet to active February
22, active to disturbed February 23, mostly quiet February 24-25,
quiet February 26-28, quiet to unsettled March 1, quiet to active
March 2, mostly quiet March 3, quiet to unsettled March 4, quiet
March 5-6, mostly quiet March 7-8, quiet March 9, and quiet to
active on March 10.
 |
| AR1654 is a Monster Sunspot |
Don't miss the article in the March issue of QST, by Carl
Luetzelschwab, K9LA titled "The Sun and the Ionosphere." It begins
on page 48, gives an update on Cycle 24, and discusses measuring the
Sun and ionosphere and relating solar flux to MUF, or Maximum Usable
Frequency.
Neil Shapiro, W2NLS of Bethpage, which is on New York's Long Island,
asked about relating the information in these bulletins to practical
on-the-air results.
I suggested checking out the resources listed at the bottom of each
bulletin, from the ARRL Technical Information Service and also the
resources from the K9LA website.
One useful tool is to download the free program W6ELprop (which
works on the Windows operating system) from
http://www.qsl.net/w6elprop/.
You will need to enter your latitude and longitude for your default
station location, and a useful tool for converting street addresses
to geographical coordinates is at
http://www.latlong.net/convert-address-to-lat-long.html.
You can use an average of the previous 5 days sunspot numbers from
here:
http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt
For the K index, either use the latest Middle Latitude numbers from
here:
http://www.swpc.noaa.gov/ftpdir/indices/DGD.txt
