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The K7RA Solar Update


The average daily sunspot number this week was down 12 points from the previous week, and the solar flux was about the same. Sunspot numbers for February 23-29 were 52, 47, 47, 58, 45, 35 and 22, with a mean of 43.7. The 10.7 cm flux was 103.3, 108.9, 108, 107, 105.5, 103.3 and 102, with a mean of 105.4. The estimated planetary A indices were 4, 6, 6, 6, 16, 10 and 6, with a mean of 7.7. The estimated mid-latitude A indices were 3, 6, 3, 7, 12, 11 and 6, with a mean of 6.9.

With February over, we can look at some of our averages and statistics for the current sunspot cycle. The average daily sunspot number for February 2012 was 50.1, the lowest monthly value since January 2011. The monthly averages for sunspot numbers since January 2011 are 32.2, 53.5, 81.1, 80.8, 61.5, 55.5, 67.2, 66, 106.4, 123.6, 133.1, 106.4, 91.4 and 50.1.

We also keep track of a three-month moving average, and the latest -- ending in February and centered on January, 2012 -- is 83.3. This is the numeric average of all the daily sunspot numbers from December 1, 2011-February 29, 2012, a period of 91 days. 83.3. It is centered on January -- which was the lowest since August 2011 -- when the average was 79.6. The three month moving averages of daily sunspot numbers centered on August 2011-January 2012 are 79.6, 98.6, 118.8, 118.6, 110 and 83.3.

The latest prediction has planetary A index for March 2-6 at 8, 8, 5, 10 and 10, then 5 on March 7-10, 8 on March 11, 5 again on March 12-16, then 12, 15, 10, 8 and 5 on March 17-21. The predicted solar flux is 105 on March 2-5, 100 on March 6-8, 105 on March 9-11, 110 on March 12-13, and 115 on March 14-18. On March 19-20, the predicted value is 110 and then down to 105 on March 21-25, and that covers the spring equinox.

The ARRL International DX SSB Contest this weekend should have fairly good conditions. It looks like somewhat unsettled conditions for Friday and Saturday, March 2-3, and quiet geomagnetic conditions on Sunday, March 4.

There is a new service that forecasts geomagnetic storms for satellite operators. You can find more details here.

From time to time, we mention silly popular press reports of large solar flares and other big space weather, but this article from Northern Scotland places the famous Carrington event at the peak of Solar Cycle 19, instead of the 19th century.

Robert Miles, K9IL, of Martin, Tennessee wrote about 6 meters: “This is the low time for most USA 6 meter operators, unless you are very far south. I have been listening for the Oceania stations that others are spotting, and on Wednesday, February 23 (0200 Thursday), I worked Remi, FK8CP, in New Caledonia on 6 meter CW, a pretty good thrill for me in EM56, in Northwestern Tennessee.” That is quite a long haul, about 7900 miles from Robert’s place on Green Acres Drive to Noumea.

Mel Frost, KD7DCR, at 6200 feet near Whitehall, Montana, writes about 6 meter plans for this year: “I just thought that I’d mention that more and more, plans to activate some rare grids here in the USA area this season (May-August) are becoming known. Some of these are personal travel plans and some are dedicated trips with only radio in mind. There is one big-circle route from Arizona to North Dakota, around Eastern North Dakota for about a month, and then back around the western side to Arizona. This one is kind of early in the year, but may work well if our Sun cooperates. Some Canadians are planning to activate the other CY0, St Paul Island. The far Northern Michigan grids (mostly water) are going to get a go, and the biggie is a special trip down into DL88, and DL79/89 is laid on with some large antennas and power. And not much said currently, but there is also a ‘floating’ operation for DM02 planned as well (very rare!). These are all concentrated on 6 meters, with some higher bands being available if open.”

Lance Collister, W7GJ, of Frenchtown, Montana, writes about moonbounce: “I noticed your comments in the last Solar Update about the low band guys enjoying the low solar activity. Actually, at the other end of the spectrum, the unusually low Kp index also makes for ideal 6 meters EME conditions! And with the greatly increasing number of newer transceivers (and amplifiers) that include 6 meters, and with more stations QRV on digital modes, many folks have 6 meter EME capability and don’t even realize it. I have been activating a rare DXCC entity on 6 meter EME for each of the last four years, and will be going to ZK2 (Niue) at the beginning of September (during the optimum time of the month for 6 meter EME). Any halfway-decent 6 meter station with good ground gain should be able to put that rare DXCC in the log during their moonset. The smallest antenna I have worked so far with my portable 6 meter EME setup was N3CXV and his M2 6M5X Yagi during his moonset. It is real magic on the Magic Band when you can make contacts halfway around the world during a poor solar cycle!”

Find more information about 6 meter EME -- and using JT65A for EME -- on Lance’s web pages:

Howard Lester, N7SO, of Schuylerville, New York wrote, “I haven’t been on HF for nearly two months, but I got on this morning (February 24) at 1600. Even with the flux at ‘only’ 103, I had a nice, but short chat on 10 meter SSB with Ljubo, 9A9DX (in Croatia), with S7-S8 signals both ways. Then, on 12 meter CW, I heard an F6 station with a booming signal from France. If this is what 10 and 12 can be like at this time of year with this level of solar flux, I have no complaints.”

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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