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Propagation Forecast Bulletin #11 de K7RA:

from W1AW Bulletin via the ARRL on March 15, 2013
Website: http://www.arrl.org/
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Propagation Forecast Bulletin #11 de K7RA:

ZCZC AP11
QST de W1AW
Propagation Forecast Bulletin 11 ARLP011
>From Tad Cook, K7RA
Seattle, WA March 15, 2013
To all radio amateurs

SB PROP ARL ARLP011
ARLP011 Propagation de K7RA

Solar indicators were mixed this week, with the average daily sunspot number down 8.4 points to 84.9, but average daily solar flux up 5.9 points to 118.5. Geomagnetic indices were much quieter, with the average planetary A index down 4.7 points to 4.4, and the average mid-latitude A index down 5 points to 3.9. The main reason for this is there weren't any active days this week, such as March 1-2 in the previous week's report.

The predicted solar flux for March 15-17 is 120, then 115 on March 18-19, 110 on March 20, 105 on March 21, 95 on March 22-24, 100 on March 25-26, 105 on March 27, 110 on March 28-31, 115 on April 1-3, then solar flux peaks around 120 on April 4-11. This prediction for solar flux at 120 on April 4-11 is fairly recent, first appearing in the March 11 forecast. Prior to that date, values were predicted around 100-105, and back before February 25, 95 was the predicted level. The predicted March 15-17 flux value of 120 is also recent. On March 6 the predicted values were 95 for that period.

The average of predicted solar flux for the next five days, March 15-19 is 118, right around the average of 118.5 for the past reporting week, March 7-13.

The predicted planetary A index on March 15-16 is 17 and 12, indicating more geomagnetic activity similar to March 1-2. The predicted planetary A index is 5 on March 17-20, 8 on March 21, 5 on March 22-27, 18 and 10 on March 28-29, and 5 again on March 30 through April 16.

OK1HH predicts the geomagnetic field will be active to disturbed on March 15, quiet to unsettled March 16-17, mostly quiet March 18, quiet to unsettled March 19-21, active to disturbed March 22, quiet to active March 23, quiet March 24-25, mostly quiet March 26, quiet to active March 27-28, quiet to unsettled March 29-30, mostly quiet March 31, and quiet on April 1-4.

At 0600 UTC on March 15 the Australian Space Forecast Centre reported that a sudden impulse of 22 nT was detected in magnetometers at 0527 UTC. Due to a CME, increased geomagnetic activity is predicted on March 15-16. Minor storm periods at high latitudes are possible.

The coronal mass ejection and M1 class solar flare were from sunspot group 1692, right in the center of the visible solar disc viewed from Earth, and was Earth-directed.

In recent online articles about a possible two-peak Cycle 24, they were talking about the peak in late 2011 and another in 2013. But I noticed recently that solar physicist Dean Pesnell of NASA is suggesting a peak in late 2013 and another in 2015. Check the last line of the first paragraph of this article posted yesterday on the ARRL website: http://www.arrl.org/news/solar-cycle-24-may-have-double-peaks-says-nasa-solar-physicist.

Robert Elek, W3HKK sent these observations about the TX5K operation on Clipperton Island:

"Kudos to the ops at TX5K! And to their nifty web site. I love the world map, spotting of call signs, almost instantaneous log updates, QSO totals, etc. It lets you see the propagation on a visual basis, call by call.

"I had not realized TX5K was on the air until, during our club effort at WW8OH for the ARRL SSB DX Contest on March 2-3, we worked them. Post-contest, and after catching up on my sleep Sunday night and most of Monday, I turned on the rig, right after dinner, and TX5K was EVERYWHERE, with big sigs! I worked them on 12, 15, 17, 30, 40 and 160 meters, many bands on both SSB and CW, during an amazing three hour stretch of operating!

"The station here is modest: 100 watts to an assortment of single band ground planes, and an inverted L for 160m. Working them so quickly, often on the very first or second call, was mind-blowing. Their pile-ups were HUGE. It had to be a miracle of good timing, plus a little experience to boot.

"I have since worked them on 160 thru 10m. Great job by TX5K! Thanks, guys!"

For a peek at the vertical antennas at W3HKK, click the photo on the upper right on his QRZ.com page at http://www.qrz.com/db/W3HKK. Note you will have to log in, but accounts are free.

Brian Alsop, K3KO of Henderson, North Carolina commented that "DXers shouldn't overlook VOACAP while chasing new ones." He sent a couple of circuit reliability plots from his location to ZL9CI and 9M4SLL on Spratly, and noted that the times he worked them lined up with the predictions. "I recently downgraded to 500 watts, a 2 element tri-bander at 40 feet and rotary dipole for 30/17/12 at 42 feet. I need all the help I can get. Besides the DX cluster, knowing what paths at what time may be possible helps."

K9LA has a tutorial on the ARRL web site for using VOACAP, and you can see it at http://www.arrl.org/files/file/Technology/propagation/Voacap.pdf.

Finally, at http://stevemorse.org/jcal/latlon.php is a handy tool for converting a street address into latitude/longitude coordinates. This is useful for determining locations for propagation prediction and other programs based on FCC database address records, or for your own location.

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 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.

Sunspot numbers for March 7 through 13 were 80, 59, 63, 89, 105, 95, and 103, with a mean of 84.9. 10.7 cm flux was 113.8, 115, 116.2, 119.2, 119.7, 123, and 122.9, with a mean of 118.5. Estimated planetary A indices were 4, 3, 6, 4, 5, 5, and 4, with a mean of 4.4. Estimated mid-latitude A indices were 2, 3, 6, 3, 4, 6, and 3, with a mean of 3.9.
NNNN
/EX

Source: W1AW Bulletin via the ARRL.

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