Propagation de K7RA

Sunspot numbers rose over the past few days. Though the average sunspot number for the past reporting week (Thursday through Wednesday) was about the same as the previous week, the emergence of sunspots 921 and 922 brought the daily sunspot number over October 29 through November 2 to 0, 15, 34, 46 and 59. This number will
probably rise through the weekend.

The increased sunspot numbers may correlate with some activity observed for the past few days on the higher bands. A glance at http://dx.dxers.info/ on Thursday evening shows that during the day, Asian Far East stations on 10 and 12 meters were hearing and working the XF4DL expedition on Socorro Island (this is in the Pacific Ocean, roughly 300 miles south of Baja California on roughly the same latitude as Mexico City). Also apparent on 10 and 12 meters is E51QMA in the North Cook Islands heard and worked by North American stations.

Helioseismology detects a new spot emerging on the far side of our Sun which should rotate to face us in a few days, around November 7. Why this, when we might be only months away from sunspot minimum, predicted to occur some time around April 2007
(see http://sec.noaa.gov/ftpdir/weekly/Predict.txt)? Attribute it to the many large short term variations we see in solar activity during any cycle.

October is over, and we now know the average sunspot number for the month (14.7) and the average solar flux (74.3). Here are the monthly averages for the past thirteen months:

The average daily sunspot numbers for the months October 2005 through October 2006 were 13, 32.2, 62.6, 26.7, 5.3, 21.3, 55.2, 39.6, 24.4 , 22.6, 22.8, 25.2 and 14.7. Average daily solar flux for the same months was 76.6, 86.3, 90.8, 83.4, 76.5, 75.5, 88.9, 80.9, 76.5, 75.8, 79, 77.8 and 74.3.

We can compare the recent monthly sunspot averages to the averages during the last solar minimum in 1996. The monthly average sunspot numbers for January 1996 through April 1997 were 18, 9.1, 12.1, 8.5, 11.9, 18.8, 13.2, 20.7, 2.9, 2.3, 25.6, 15.1, 8.7, 11.4, 13.7, and 24.5. We see the lowest numbers were in September-October 1996, and six months prior to that, the numbers weren't far off from what we've seen for the past three months, 22.8, 25.2 and 14.7.

Last week was the phone weekend of the CQ World Wide DX Contest. Geomagnetic conditions were a bit unsettled. This weekend is the CW weekend for ARRL Sweepstakes, and conditions should remain quiet through the weekend, with increased sunspot numbers. Many contesters would rather see those conditions on a DX contest weekend, but we can't complain. The predicted planetary A index (lower numbers
indicate more stable geomagnetic conditions), for November 3-9 are 8, 8, 5, 5, 5, 5 and 20. Geophysical Institute Prague predicts unsettled conditions for November 3, quiet to unsettled November 4, quiet conditions November 5-7, quiet to unsettled November 8, and unsettled to active November 9.

Larry Godel, W0OGH in Gilbert, Arizona reports that he experienced good 10 meter FM openings last weekend to California and Texas. He was able to work through the W5DFW repeater and another near Yosemite in California with full-quieting signals. He comments that on Sunday morning, "on the 40 meter AM net, local stations (those
within 100 miles) were strong as 20db over S9. Within 5 minutes they were gone and within half an hour they were all back, strong as ever. Conditions stayed that way for several hours thereafter."

Finally, I don't know if this fellow in Quebec is a ham operator, but he should be. This illustrates a personal fantasy I had as an 11 year old. Problem was, it was 1963, and we didn't have the technology yet. Take a look at these videos at,
http://tinyurl.com/n7agv and http://tinyurl.com/ms6t2.

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 at,
http://www.arrl.org/tis/info/propagation.html.

For a detailed explanation of the numbers used in this bulletin see, http://www.arrl.org/tis/info/k9la-prop.html.

An archive of past propagation bulletins is at, http://www.arrl.org/w1aw/prop/.

Sunspot numbers for October 26 through November 1 were 0, 2 14, 28, 0, 15, 34 and 46 with a mean of 19.9. 10.7 cm flux was 71.9, 72, 74.7 , 73.3, 75.7, 80.1, and 86.7, with a mean of 76.3. Estimated planetary A indices were 1, 2, 14, 21, 9, 4 and 6 with a mean of 8.1. Estimated mid-latitude A indices were 1, 3, 12, 13, 6, 2 and 5, with a mean of 6.

Source: The American Radio Relay League