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The K7RA Solar Update


We had some nice sunspot activity from July 3-10 -- and we were hoping for a return 27-28 days later -- but it never happened. Varying by latitude, the Sun rotates relative to Earth about every 27.5 days. If that same region was still active or the activity renewed, we might have seen something July 30-August 7, which is today. Instead, the quiet continues.

Sunspot numbers for July 30-August 5 were 0, 0, 0, 0, 0, 0 and 0 with a mean of 0. The 10.7 cm flux was 68, 68.7, 68.1, 68.1, 67.4, 65.8 and 66.2 with a mean of 67.5. The estimated planetary A indices were 3, 5, 4, 3, 10, 4 and 6 with a mean of 5. The estimated mid-latitude A indices were 2, 4, 3, 2, 7, 4 and 5 with a mean of 3.9. The predicted planetary A index for August 7-11 is 5, 5, 7, 5 and 5. Some rather odd numbers appeared on August 5. Check out the eight planetary K index readings on that date and note that they never varied.

Dean Lewis, W9WGV, of Palatine, Illinois, wrote this week asking about the most likely path that his signal took on July 12. Because of local restrictions, he uses inside wire for an antenna, so he can't tell for sure which direction a signal is coming from. He worked VK2AYD on 20 meter CW at 0620 UTC in the IARU HF World Championship. He wondered if the path was most likely over the Pacific, or the Atlantic Ocean and Africa.

I ran some numbers on W6ELprop and used a location of 42.148 degrees North and 88.014 degrees West for Dean. According to the entry on, VK2AYD is in grid square QF68in, which W6ELprop translates to 31.44 degrees South, 152.71 degrees East. W6ELprop indicates that the short path is 9069 miles, with a beam heading from Illinois of 262 degrees. Long path is at 82 degrees from Dean, at 15,806 miles.

With a smoothed sunspot number of 3, it shows that they worked each other at the optimum time for that band. From 0400-0600 UTC, the program predicts signals at 19, 21, 23, 24 and 25 dB above 0.5 microvolt on half hour intervals. After that, signals drop out -- this is exactly what Dean experienced. Any possible long path opening would be much weaker and also earlier, according to the software. It says 2300-0000 UTC is most likely.

Among 6 meter reports this week, Bill Turner, W4WNT, says he was mobile running 40 W on the beach at Oak Island, North Carolina (FM03), when he worked EA8CQS (IL18) in the Canary Islands on phone on July 29. Bill was using one of those popular and inexpensive monoband whips on the back of his car.

Jon Jones, N0JK, of Wichita, Kansas, had a lot of 2 meter E-skip excitement on July 29-30, but missed openings the following day. On July 29, he worked W1AIM (FN34 in Vermont) at 2242 UTC; K1WHS (FN43 in Maine, 2300 km away -- heard off and on for over an hour!) at 2245 UTC; W2RJO (FN23 in New York) at 2252UTC; KC2RDC (FN14 in New York) at 2332 UTC, and VE2DFO (FN25 in Quebec, Canada) at 2349 UTC. He sent a link showing the K1WHS station. Jon was using a 7-element Yagi on a stepladder in his bedroom. It was facing northeast, but Jon didn't say it the antenna was pointed out the window!

George Ackinclose, W4GNE, of Chesterfield, Virginia, had an exciting time with that same sporadic-E 2 meter opening on July 29 from 2200-0000 UTC. He was using a 12-element Yagi on a 20 foot boom, but just 25 feet above ground. George reports that he worked "K0AWU (EN37 in Minnesota -- about 1000 miles away); K0SIX (EN35 in Minnesota); KA9CFD (EN40 in Illinois); WB0ULX (EN04 in South Dakota -- approximately 1200 miles away); K0KFC (EN35 in Wisconsin); K0CJ (EN34 in Minnesota), and N0UK (EN34 in Minnesota). I have only been in Amateur Radio since December 2002, and that was the most heart racing, adrenaline pumping action on any band that I have been a part of -- so far! I'm certain that if I had a little better antenna height, I would have worked a lot more; I heard many others just too far down in the noise for me to pick out". All these contacts had good signals, S5-S9."

Roger Harrison, VK2ZRH, sent an interesting e-mail concerning a 3-month running mean of sunspot numbers he has been looking at. You can see his analysis and discussion here. Roger wrote: "During the late 1980s, I worked with Dr Leo McNamara to produce a series of nine articles titled "Radio Communicators' Guide to the Ionosphere," published in Australian Electronics Monthly (I was Editor/Publisher); Dr McNamara subsequently developed that into a book -- Radio Amateurs Guide to the Ionosphere, published by Kreiger. More recently, from around 2002, I began re-acquainting myself with the world of sporadic-E research and sporadic-E VHF propagation."

This weekend is the Worked All Europe DX CW Contest. Conditions should continue to be quiet, although currently on Friday morning, the interplanetary magnetic field is pointing south, leaving our Earth vulnerable to a solar wind stream.

Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears in The ARRL Letter. Check here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.



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