Propagation de K7RA - 2 March, 2013

15:41 Fernando Luiz de Souza 0 Comments



2 March, 2013


Solar and geomagnetic activity over the past week (Thursday through Wednesday, February 21-27) declined, with the average daily sunspot number dropping nearly 21 points to 57.7. Average daily solar flux softened by 4.7 points to 100.9, and average daily planetary A index declined 6.4 points to 5.1. This isn't much of a change, but geomagnetic activity was low already, and this is even lower.

Predicted solar flux for the near term is 110 on March 1-3, 105 on March 4-7, 100 on March 8, 95 on March 9-14, 100 on March 15-16, 105 on March 17, and 110 on March 18-20. Solar flux then reaches a peak of 120 on March 25-27, and on March 28 through April 6 maintains an average around 113.
The predicted planetary A index is 12 and 8 March 1-2, 5 on March 3-4, 8 on March 5, 7 on March 6-7, 5 on March 8-10, 7 on March 11-12, and 5 on March 13-20.

OK1HH predicts quiet to active geomagnetic conditions on March 1, mostly quite March 2, quiet to unsettled March 3, quiet on March 4, mostly quiet March 5, quiet to unsettled March 6, quiet to active March 7, quiet on March 8, mostly quiet March 9-10, quiet to active March 11-12, quiet to unsettled March 13-16, mostly quiet March 17-18, quiet to unsettled March 19-21, active to disturbed March 22 and quiet on March 23-24.
It is interesting to note that OK1HH predicts active to disturbed conditions on March 22, but NOAA and USAF predict a benign planetary
A index of only 5 on that date.

This weekend is the ARRL International Phone DX Contest, from March 2, 0000z to March 3, 2400z. If you are on the West Coast, and use Pacific Standard Time, that would begin at 4:00 PM on Friday, ending at 4:00 PM on Sunday. For more info, check http://www.arrl.org/arrl-dx.
With February ended, let's look at some updated averages. Our most recent 3-month moving average does not impress. The three months centered on January 2013 had an average daily sunspot number of 73.6. This is below every three-month moving average for last year, except the three months centered on March 2012, which was 71.2. The 3-month moving averages of daily sunspot numbers centered on January 2012 through January 2013 were 83.3, 73.7, 71.2, 87.3, 91.5, 96.5, 91.9, 89.9, 81.2, 82.3, 74.4, 82.8 and 73.6.
Jim Henderson, KF7E sent a link to an impressive NASA clip of solar activity from last July. Note that you can set this video to HD resolution, and it looks great on full screen. See it athttp://apod.nasa.gov/apod/ap130226.html.
Also check out the photo gallery of solar events at
http://news.cnet.com/2300-11386_3-10015988.html and note the dramatic composite image number 4.

Walt Knodle, W7VS sent an article about artificial ionosphere produced by the HAARP facility in Alaska with a 3.6 megawatt signal on 69 meters. Note that they are only able to produce the effect for 45 seconds. Read about it at http://phys.org/news/2013-02-scientists-densest-artificial-ionospheric-plasma.html.
I think the Wikipedia page at http://en.wikipedia.org/wiki/
High_Frequency_Active_Auroral_Research_Program
 gives a pretty good overview of the HAARP project.
Also the September 1996 issue of QST has a nice article by K3NS titled, "The High Frequency Active Auroral Research Program." ARRL members can find and download it from the ARRL website with a search athttp://www.arrl.org/arrl-periodicals-archive-search.

Jim Smith, K3RTU operated on HF CW from Ridley Creek State Park in Southeast Pennsylvania (FM29) on February 25. He wrote, "I hooked up with EA8BVP in the Canary Islands. 'Bal' EA8BVP was using a FT-817 and a vertical, and I was using my FT-817 and my trusty Buddistick vertical. This CW QSO took place early in the afternoon on 18.086 MHz. I had been trying to make a contact on 20 meters and was having no luck so I QSYed to 17 meters and almost within minutes heard EA8BVP calling CQ. Both of our signal levels were S4 to S5. I frequently operate on 17 meter CW while out backpacking and more often than not it provides me with good long distance contacts."
It looks like the path from the park to the Canary Islands would be good in the early afternoon, with the best 17 meter signals that day from 1200-2200 UTC. 17 meters does look like a better bet, with 20 meters not catching up until after 2000 UTC.
If you would like to make a comment or have a tip for our readers, mail the author at, k7ra@arrl.net.
For more information concerning radio propagation, see the ARRL Technical Information Service 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 ofpast propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation.
Find more good information and tutorials on propagation at
http://myplace.frontier.com/~k9la/.
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 February 21 through 27 were 75, 79, 56, 25, 59, 49, and 61, with a mean of 57.7. 10.7 cm flux was 108.5, 107, 99.6, 94.9, 95.4, 98.7, and 102, with a mean of 100.9. Estimated planetary A indices were 6, 9, 6, 3, 3, 5, and 4, with a mean of 5.1. Estimated mid-latitude A indices were 5, 9, 6, 2, 3, 4, and 4, with a mean of 4.7.

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