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ARRL Propagation Bulletin ARLP009 (2013)

ARLP009 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 9  ARLP009
From Tad Cook, K7RA
Seattle, WA  March 1, 2013
To all radio amateurs 

ARLP009 Propagation de K7RA

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

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 at

Also check out the photo gallery of solar events at 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

I think the Wikipedia page at
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

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,
email the author at,

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at For an explanation of the
numbers used in this bulletin, see An archive of past
propagation bulletins is at Find more good
information and tutorials on propagation at

Monthly propagation charts between four USA regions and twelve
overseas locations are at

Instructions for starting or ending email distribution of ARRL
bulletins are at

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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