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The K7RA Solar Update


Solar Cycle 24 is slowly building momentum. We saw sunspots for eight days in a row -- October 10-17 -- then 12 days of no spots. Another sunspot -- number 1007 -- appeared on October 30 from Solar Cycle 24. It is a high latitude sunspot and may provide some fun for this weekend's 75th running of the ARRL CW Sweepstakes.

Sunspot numbers for October 23-29 were 0, 0, 0, 0, 0, 0 and 0 with a mean of 0. The 10.7 cm flux was 67.2, 67.5, 67.5, 66.9, 67, 67.1 and 66.7 with a mean of 67.1. The estimated planetary A indices were 3, 2, 1, 4, 1, 4 and 11 with a mean of 3.7. The estimated mid-latitude A indices were 3, 0, 1, 3, 1, 5 and 16 with a mean of 4.1.

So what does the upcoming week hold? I don't know how long this new sunspot will remain. According to the US Air Force and NOAA Space Weather Prediction Center, the planetary A index is predicted at 8 for October 31, then a nice low index of 5 for November 1-6. But November 7, look for a big geomagnetic upset, complete with more absorption on HF, especially over polar paths with a planetary A index of 35. But this may also give VHF operators some nice auroral reflections. The same forecast does not predict sunspot numbers, but solar flux, which has been right around 67 since October 26. They predict solar flux at 69 for November 1-6, then 70 for November 7-12.

Geophysical Institute Prague predicts "Relative sunspot number in the range 0-25" for October 31-November 6. They forecast unsettled geomagnetic conditions for today, October 31, quiet to unsettled November 1, quiet conditions November 2-5 and quiet to unsettled November 6. It is possible that around November 4 we may see a return of sunspot number 1005.

After a calendar year of very few sunspots, this is the fourth time during October that sunspots have emerged, and all from the new Solar Cycle 24. For a comparison, we look at W6ELprop to compare zero sunspots over this weekend to several days of two sunspot groups (a sunspot number of 24, for example). We will look at two paths: The first from Beaverton, Oregon to Savannah, Georgia, and the second from Cleveland, Ohio to Central California. Because this is a contest weekend, we will only consider the five bands used in most contests: 80, 40, 20, 15 and 10 meters.

  • From Oregon to Georgia, with zero sunspots we see little or no likely 10 or 15 meter propagation. Twenty meters looks good from 1700-2030 UTC.

  • Propagation on 40 meters is best from 2230-0130 UTC, fair from 0900-1100 UTC, signals may disappear around 1330-1430 UTC; there is propagation building throughout the day from 1500-0130 UTC with the weakest daylight signals around 1730-1900 UTC.

  • Eighty meters looks strong 0200-1130 UTC z from after sunset in Oregon until prior to sunrise in Georgia.

  • With a sunspot number of 24 for several days, 15 meters has a possible opening 1830-1930 UTC, 20 meters 1600-2200 UTC and 40 meters looks good 2200-0430 UTC. Then we'll see excellent signals 0800-1300 UTC and weakest 1630-2000 UTC. Propagation on 80 meters should be about the same as with no sunspots.

  • From Ohio to California, with zero sunspots, 15 meters might open 1600-2130 UTC, with a better chance 1730-1930 UTC. Twenty meters should be good 1430-1500 UTC, then 1700-2000 UTC and 2200-2330 UTC. Forty meters should be open nearly around the clock, with weak signals around 1300 UTC, strongest signals 0100-1230 UTC and strong again at 1400 UTC and again at 2300 UTC. Eighty meters should open after 2200 UTC, with strongest signals 0300-1200 UTC and weak or no signals during daylight from 1500-2200 UTC.

  • With a sunspot number of 24 sustained for several days from Ohio to California, 15 meters comes alive with excellent signals for most of the day, 1630-2130 UTC. Twenty meters opens 1400-0030 UTC with weak spots at 1530 UTC and 2100 UTC. Forty meters should be open 24 hours a day, with strongest signals 0100-1230 UTC, then again around 1400 UTC and 2300 UTC, weakest 1700-2000 UTC. Eighty meters looks about the same, but opening slightly later than with zero sunspots.

Propagation programs give us some general guides to openings, based on statistical models using smoothed sunspot numbers.

Bob Parkes, G3REP, of West Sussex, United Kingdom, sends along an interesting link about visualizing the ionosphere, a subject not mentioned in this bulletin for some time (we covered the subject earlier this year on May 2). Bob is now semi-retired, but his telecom engineering work over the past few decades has taken him all over the world. He was VS5RP Brunei in 1979-1981, P29PR in Papua New Guinea in 1983-1987, A45XF in Oman from 1992-1993 and 4S7RPG in Sri Lanka in 1993-1997. You can read his bio and find a link to his photo here.

Joaquin Montoya, EA2CCG, wrote this week about conditions last Friday, October 24. He turned on his mobile rig to check conditions before the CQ World Wide DX contest and found everything dead in the dead of night. Conditions were also poor throughout the weekend from his location in Spain. But on October 29, perhaps around the time our new sunspot 1004 appeared, he worked WH2P (Guam) on 15 meters. He didn't say what time that was, but I might wager that it was during his morning hours from 0700-1100 UTC, perhaps around 0900 UTC. Joaquin has a very interesting blog at that I found along with his photo.

Just before this bulletin was released, Joaquin wrote: "I worked WH2P at 0937 UTC 29 October. Today 31 October we also have good conditions...and a surprise. On this moment at 1647 UTC listening to LU on 15 meters. This morning I worked VU7NRO on 15 meters, weak but workable. Suddenly 10 meters were also opened, listening to some European beacons. At 1111 UTC, I caught a sporadic-E opening on 6 meters and worked 8 European stations from OK, DL, OE and 9A. What a day!" So the "wager" about 0900 UTC turned out to be not far off. This was done looking at W6ELprop, assuming one sunspot.

Many of us in the US (myself included) unfortunately only speak one language, English, and sometimes not that well. But I used the language tool here and pasted the blog's URL into the http:// field under "Translate a web page." Although the translation is rough (sometimes laughable), and considering that a mere AI machine did this, the result is pretty impressive; you can definitely understand Joaquin's fine writing. Check it out -- this is really a great blog about Amateur Radio with impressive photos and other graphic images.

Dave Fisher, KA2CYN, of New City, New York, says that during last week's contest on 10 meters with a roof-mounted rotatable multi-band trap dipole, he worked a number of South American stations, the furthest "in Brazil and Argentina." He wonders if it could be F2 propagation, but this was probably E-skip. W7FA (see last week's bulletin) reports more 10 meter propagation from Oregon on October 22, 2100-2130 UTC, a short opening to LU and PY, just like KA2CYN a few days later.

Also, Jim Henderson, KF7E, in Arizona said, "VU4MY was actually workable on 14.240 MHz this morning. Good sign!" Local morning for Jim might be 1300-1700 UTC. Jim also reported some 17 meter long path propagation to a station that turned out to be a fake, so he doesn't really know where it was. He wrote, "Back in early 1972, there was a guy signing ZK2 something, with the name of 'Back' or 'Bach.' He would show up every other week or so. In about July of that year, I found myself on Niue as ZK2DX (the original issue of that call). On one of my first nights operating, there was ZK2?? with a grand pile on 20 meters. I would have loved to have seen his face when I called him and said 'Please tell me where on the island you are because I would love to come visit your shack.' He vanished forever!"

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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