Solar activity increased over the past week, with average daily sunspot numbers rising from 129 to 135.6, while average solar flux increased by nearly 13 points to 154.3. This compares the recent March 20-26 period with the previous seven days, March 13-19.

The latest predicted solar flux from the current 45 day forecast has 10.7 cm flux values at 145 on March 28-29, 140 on March 30 through April 2, 135 on April 3-4, 150 and 155 on April 5-6, 160 on April 7-8, then 155, 150, 145 and 140 on April 9-12, 145 on April 13-14, 150 on April 15-17 and 145 on April 18. Solar flux peaks at 160 on April 22 and again on May 4-5.

Predicted planetary A index is 5 on March 28 through April 8, 10 on April 9, 5 on April 10-16, then 8, 7,7, 10 and 8 on April 17-21, then 5 until April 25, when for three days the planetary index is 8, on April 26-28.

OK1HH believes that the geomagnetic field will be quiet to active on March 28, mostly quiet March 29-30, quiet to unsettled March 31, quiet to active April 1, quiet April 2-7, quiet to active April 8, mostly quiet April 9, quiet to unsettled April 10-11, quiet April 12, quiet to unsettled April 13, mostly quiet April 14-15, quiet on April 16, quiet to active April 17, mostly quiet April 18-19, quiet to active April 20-21, and quiet April 22.

OK1HH says we may see enhanced solar wind on 8, 11, 13-14 and 20-21.

OK1HH also sent along some photos from the first day of spring, at https://www.dropbox.com/sh/36kbsoqzou1tdbd/ATLb7dVOu3 . You can see the Ondrejev Observatory and an interesting sculpture (images 2-5) which catches the sunlight at local noon on both the autumnal and vernal equinox and also the winter and summer solstice. I believe images 7 and 8 were photographed from the observatory deck shown in image 9. OK1HH says the observatory is a 10 minute walk from his home. It has a Facebook page at https://www.facebook.com/AstronomickyUstav.

Concerning the sculpture, OK1HH wrote, “Sculpture has one vertical and three horizontal cut notches. In places where they intersect, sunbeam penetrates the holes in the intersection when the astronomical equinox and the summer and winter solstice around local noon. Sunbeam penetrated on 20-21 April 2014 around 12:07 CET.”

Jon Jones, N0JK, is in Oahu this week, and says he worked VK, ZL, FK and 5W on 6 meter trans-equatorial propagation.

Bill Billingsly, N5IR, of Sanger, Texas sent a report about his experiences on 17 meters on March 23. “I rarely work SSB, but saw HB9CVQ spotted on 18.143 MHz. I have worked Andy many times on CW, so I called him. We had a continuous SSB QSO from 2151Z to 2334Z. Andy was running a KW into a 3-el SteppIR at 60 ft and his signal was mostly 59+15 with two short dips to 56. I was running 200 watts into a 2-el Yagi at 70 ft. I received about the same reports.

“I had to quit for dinner and didn't return until 0029Z. HB9CVQ was still there at 57. I moved down to 17 meters CW and worked 8Q7TS over the pole. He was 579 here in NTX. I went back to HB9CVQ at 0050Z and he was 59+15 again. I had just a little gray light left outside. I called him again and he gave me a 58. Andy mentioned that the band had taken one big dip after our earlier QSO, but soon recovered. He had been going strong since I left for dinner.

“Happy days are here again!”


Don’t forget the CQ World Wide WPX SSB Contest this weekend. The CW portion is on May 24-25. See http://www.cqwpx.com/ for details. HF propagation should be good.


For more information concerning radio propagation, see the ARRL Technical Information Service 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. More good information and tutorials on propagation are at http://k9la.us/.

Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins.

Sunspot numbers for March 20 through 26 were 137, 125, 159, 159, 132, 114, and 123, with a mean of 135.6. 10.7 cm flux was 151.3, 152.6, 154.9, 157, 158.6, 152.8, and 153.2, with a mean of 154.3. Estimated planetary A indices were 6, 10, 6, 6, 5, 8, and 9, with a mean of 7.1. Estimated mid-latitude A indices were 4, 10, 7, 7, 4, 7, and 7, with a mean of 6.6.