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The K7RA Solar Update


The average daily sunspot numbers this week were up 57 percent over the previous seven days, rising from 41.6 to 65.6, while the average daily solar flux rose just 3 points to 89.1. There seem to be plenty of sunspots of late, but none have been large, and so the sunspot number and solar flux are not as high as in some previous months. A new sunspot appeared on July 7, then three more the next day on July 8, and then a new one each day on July 9, 10 and 11, and two more on July 13, with another two on July 14. A coronal mass ejection on July 9 gave us some geomagnetic activity a couple of days later. Sunspot numbers for July 7-13 were 42, 65, 55, 67, 72, 62 and 96, with a mean of 65.6. The 10.7 cm flux was 85.5, 85.8, 85.6, 90.7, 90.1, 91.7 and 94.6, with a mean of 89.1. The estimated planetary A indices were 6, 8, 12, 12, 13, 8 and 8, with a mean of 9.6. The estimated mid-latitude A indices were 6, 6, 10, 8, 10, 7 and 6, with a mean of 7.6.

The current forecast shows the planetary A index for July 15-24 at 5, 5, 5, 8, 8, 12, 12, 8, 8 and 5. Solar flux is predicted at 94 on July 15-17, 92 on July 18-19, 90 on July 20-21, then 94, 90, 89, 87, 87, 89, and 88 on July 22-28. Geophysical Institute Prague says look for quiet to unsettled geomagnetic conditions on July 15, quiet July 16-17, unsettled July 18, unsettled to active July 19, unsettled July 20 and quiet to unsettled July 21.

Jeff Hartley, N8II, of Shepherdstown, West Virginia, sent in a report on recent 6 meter activity. He wrote: “The recent somewhat lower solar flux is noticeable on the bands, late night openings to Europe on 15 are curtailed and 17 meters is slow to open to anywhere in our morning. On July 8, I got up late to find a very good 6 meter opening to Europe. The first station I heard was DK1DAX, who rapidly faded down, followed by EA7KW (who is always there when the band is open), then G8BCG who I managed to work. Then the Mediterranean area really started to come through well around 1435 and I worked IS0GQX, F5PAU, CT1DVV, CT1EWX, EA7RM and another F5. I also worked ZB2FK (Gibraltar) for a new country. On Sunday, July 3, I finally logged PJ6D around 2300 after hearing them on Field Day for quite a stretch, but my weak signal could not be heard there. Around June 29, SM5EDX was the only signal heard on 6 meters at 2115, besides a few direct signals on the East Coast calling him. There have been quite a few 6 meter European openings into W1, W2, southern W4 and the Midwest that did not extend into my area.”

Thanks, Jeff!

Robert Elek, W3HKK, of Johnstown, Ohio, writes: “On Thursday, July 7 around 2300, I saw a nice 6 meter opening to Portugal with three strong (57 to 59) signals arriving in Central Ohio from CT1s HZE/HZJ/FFU. Signals were in and out for several hours centered on 2300. Then on Friday morning, July 8, it hit the fan in Central Ohio! I worked CT1FFU and HZE again, stronger than the night before, and then witnessed nearly all of Western Europe coming through, one by one, building up out of the noise to around 55/559 and sometimes -- as in the case of IS0GQX -- up to 59. It seemed GQX was in there from around 1300 until the band quieted down around 1800. Kudos for an amazing signal! Meanwhile, I had fun working F8DBF, ON5HJS, 9H1BT and EA7KW -- all new countries for me -- and a couple of Canadian Maritimers. But alas, the hoped for evening opening didn’t materialize in Central Ohio, although I saw the Europeans were still on, but working W6s and W7s and W5s”. Imagine all this DX with 100 W to a 5 element Yagi towering 10 feet above the rear patio, ‘equipped’ with an Armstrong rotator! Six meters is indeed the Magic Band. This was the most widespread DX opening I have seen in my two years on the band. I heard stations from England, Italy and Russia as well. Very cool opening!”

Thanks, Robert. As the kids say, “Awesome!”

We get a lot of e-mail about solar activity, including some from non-hams curious about something they read in the news. Some people mention that in the same week, they see articles claiming we’re in for some sort of dangerous solar maximum, but then they read about a dearth of sunspots. I ran across thisat a NASA site, which reminds me of some of the questions I get. This interesting piece is about a big solar event 11 years ago.

Pat Moore, AL7L, of Juneau, Alaska pointed out that perhaps the use of the word “millennia” in the last bulletin was unintended, as “millennia” is plural, while “millennium” is singular.

Dick Bingham, W7WKR -- who used to live in my Seattle neighborhood -- now lives way off the grid at Stehekin, Washington, reachable only by boat or a very rugged mountain trail. Dick sent an article and video from NASA about a dark solar explosion that continues to baffle and fascinate over a month after the event.

Mike Schaffer, KA3JAW, loves to DX TV and FM broadcasts in Tampa, Florida, and reports some intense sporadic-E propagation on July 11-12. He writes: “On Monday, July 11 at 2310, I was getting traces of black-and-white video with occasional audio from a unidentified Canadian TV-6 broadcaster via sporadic-E that continued up until 0235 (9:35 pm EDT). I do not recall ever having E-skip all the way up on channel 6 (83.25 MHz video/87.75 MHz audio) this late in the evening from Canada. The next day at 1730, I heard one unidentified Cuban TV-6 audio on 87.7 on the car radio. Five minutes later I tuned up to 107.7 with a reception of an unidentified Mexican station. Both stations had fluctuating signal strengths from moderate to strong with a slow rate of fading. While remaining on 107.7 for the next hour, I heard an advertisement for about one minute, then fading away. Twenty minutes later, the signal came in with a moderate signal strength at the best possible time giving its identification spot, ‘107.7 The Bay.’ The reception distance was 1191 air miles from Alpena, Michigan to Tampa, Florida. That would place the E-skip plasma cloud overhead of Rogersville, Tennessee.”

Mike got a confirmation from the manager of the broadcast station that indeed he had received WHSB on 107.7 MHz. Mike mentioned that he received the signal using the back-side of a cross-phased multi-element antenna.

Joe Miller, KJ8O, of Troy, Michigan, writes about some curious propagation he experienced: “For the past five years, I have worked the IARU Championship and/or Field Day, and I have worked stations on 20 meters that are in the 200-300 mile range, as opposed to the usual 600-700 mile or further first skip. I have noticed this short propagation only occurs in late June and early July. The big surprise for me this year was working AC8G in Dayton, Ohio at 1515 on Saturday, July 7 on the 15 meter band at a distance of 212 miles. I contacted him and he stated that he was using a tower of about 62 feet and a 4-element Yagi pointed toward Europe and running about 900 W. On my end, I have a 5BTV and was running 100 W. His was a good solid signal, not the kind usually heard by backscatter.”

Joe wondered what was happening to enable this propagation. We ran this by Carl Luetzelschwab, K9LA, who answered that the time period suggests sporadic-E: “We normally think of sporadic-E on 6 meters and even on 10 meters. We usually don’t think of sporadic-E extending down to the lower frequencies. But if the electron density is high enough to refract 6 meters, then it’s high enough to refract lower frequencies like 15 and 20 meters. The limiting factor determining the effect of sporadic-E on these lower frequencies is the thickness and extent of the sporadic-E cloud. It has to be thick enough and wide enough (at least several wavelengths) to allow a gradual bending (refraction) to occur. More than likely, the thickness is the true critical parameter. Perhaps the thickness and extent was sufficient to allow short skip on 15 meters on your path. And with enough electrons to refract 50 MHz -- I saw many 6 meter spots over the weekend – it’s also possible that reflection could have been involved on 15 meters, which says the cloud would not have to be as thick nor as wide.”

Carl looked at the Millstone Hill (Massachusetts) ionogram for July 7 at 1515: “Of course, it’s not near Joe’s path, but it’s the closest we have! Note that sporadic-E was occurring, and the ordinary wave sporadic-E critical frequency was reported as 4.28 MHz and the extraordinary wave sporadic-E critical frequency (the green echoes at the same virtual height) was up to 5 MHz. These critical frequencies couldn’t support high-angle 15 meter propagation, but we just don’t know the magnitude and extent of sporadic-E on Joe’s specific path. All we can say is sporadic-E was occurring in Massachusetts, and the 6 meter spots suggest it was also occurring elsewhere.

“Other possibilities are an F region anomaly, but not too likely as the summer months are generally quiet and have the lowest F region electron densities (for what it’s worth, the sparse Millstone Hill data says high-angle F region propagation over your path couldn’t be supported, either). As for a geomagnetic disturbance as suggested by your friend, I see that the A and K indices were not elevated on July 7, so that would be tough to couple to your QSO. Another possibility could be extremely long ground wave (I can easily work Toledo and Dayton on 15 meters from Ft Wayne) but the signals would be weak. A last possibility would be some kind of scatter mode, but again with weak signals.”

Thanks, Carl. Great analysis!

All times listed are UTC, unless otherwise noted.

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 each Thursday in The ARRL Letter. You can find a guide to articles and programs concerning propagation here. Check here and 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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