ZCZC AP17
QST de W1AW
Propagation Forecast Bulletin 17 ARLP017
>From Tad Cook, K7RA
Seattle, WA April 28, 2006
To all radio amateurs

SB PROP ARL ARLP017
ARLP017 Propagation de K7RA

Geomagnetic conditions were quiet this week in most places, but onApril 22 there was a geomagnetic storm at high latitudes caused bysolar wind and a south-pointing IMF. The college A index inFairbanks Alaska reached 38, and the K index was 7 at its highest.The mid-latitude A index for the day was only 10, just slightlyunsettled.

On April 27 there was a strong but brief solar flare from sunspot875, but this is not expected to cause major geomagnetic activity.At the time of the flare, around 1552z, x-rays caused a short radioblackout of nearly a quarter hour.

Sunspot numbers and solar flux have been rising, and solar flux isexpected to remain around 100 over the next week. Geomagneticconditions may become active again around May 2 and May 6, with abig increase in activity around May 10-13 expected because ofsimilar activity during the previous solar rotation.

Steve Lybarger, NU7T of Reno, Nevada wrote asking about sunspotpolarity, and where he could get information on the actual polarityof currently visible spots. I told him I didn't know, but did findthis interesting page from "Mr. Sunspot's Answer Book" at theNational Solar Observatory web site, http://eo.nso.edu/MrSunspot/answerbook/polarity.html.

Ron Wright, ZL1AMO (and others, including AE6RR) wrote in to saythat ZK1JD, mentioned in last week's bulletin as worked by VA7GO, isnot actually in the South Solomon Islands, an area of great civilunrest currently. Jim Ditchburn, ZK1JD is actually in Rarotonga inthe South Cook Islands. Craig Bradley, AE6RR worked ZK1JD a few daysago on 20 meters, and when told about his call appearing in thebulletin, Jim commented that he "would not want to be in the SolomonIslands at this time!"

Greg Andracke, W2BEE of Pine Plains, New York tells about someunexpected propagation from a couple of weeks back. On Saturday,April 15 at 1123z he heard VQ9LA of Chagos calling CQ on 30 meterswith no takers. Greg scrambled to tune his 20-meter vertical to 30meters, and reached VQ9LA, neither station having strong signals.Afterward Greg could hear no other stations called the DX station.Odd propagation for that time, but it would have been normal about10-14 hours later.

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 and an explanationof the numbers used in this bulletin, see the ARRL TechnicalInformation Service propagation page at, http://www.arrl.org/tis/info/propagation.html. An archive of pastpropagation bulletins is at http://www.arrl.org/w1aw/prop/.

Sunspot numbers for April 20 through 26 were 30, 14, 15, 24, 38, 33and 60 with a mean of 30.6. 10.7 cm flux was 78.7, 76.4, 82.4, 86.7,92.8, 95.1, and 100, with a mean of 87.4. Estimated planetary Aindices were 5, 8, 18, 8, 7, 5 and 5 with a mean of 8. Estimatedmid-latitude A indices were 3, 6, 10, 8, 4, 1 and 2, with a mean of4.9.
NNNN
/EX

Source: W1AW Bulletin via the ARRL.