Warning of increased geomagnetic activity and DX propagation

Sunspot numbers pulled up from 0 this week, but barely. Average daily sunspot numbers rose over nine points to 12.9. Geomagnetic conditions were quiet. Conditions have been quiet for so long that we may not appreciate this, as many of us wish for more solar activity and sunspots.

It wasn’t long ago when we had more sunspots, but the accompanying geomagnetic activity made conditions difficult. Check the Planetary A index in October 2002, April, June, September and December 2003, and into January 2004. For 2003, check http://www.sec.noaa.gov/ftpdir/indices/old_indices/2003_DGD.txt. For any other year, just change 2003 toward the end of the URL, and to check sunspot numbers change DGD to DSD at the end of the URL.

If you read ARRL Propagation Bulletins from back then, in addition to complaints about the higher geomagnetic activity, you’ll find stories of better VHF propagation during periods of geomagnetic disturbance. You can see old bulletins back through 1995 at, http://www.arrl.org/w1aw/prop/.

The Australian Ionospheric Prediction Service sent out a warning of increased geomagnetic activity centered on September 1 due to a wind stream from a solar coronal hole. They predict, August 31, will be quiet with increasing activity late in the day, unsettled to active conditions with possible minor storm on Saturday, September 1, and mostly unsettled conditions September 2.

Geophysical Institute Prague predicted earlier that August 31 would be quiet to unsettled, September 1 unsettled to active, unsettled conditions September 2-3, quiet September 4-5, and unsettled to active again on September 6.

Over the same period the US Air Force predicts a Planetary A index of 15, 25, 12, 12, 8, 5 and 15 for August 31 through September 6.

From the same prediction, it looks like September 8-17 may see a return of 0 sunspot days.

QST de W1AW Propagation Forecast Bulletin 36 ARLP036 From Tad Cook, K7RA Seattle, WA August 31, 2007 To all radio amateurs

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David F1JXQ - Ham Radio - Web 2.0 - QTH France (Aix les Bains 73) Locator JN25wq - Former TO1USB and FG/F1JXQ - 14Mhz - 28Mhz - 50 Mhz - 144Mhz - SSB & PSK31 DX