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The K7RA Solar Update


The autumnal equinox occurred early yesterday, at 0309 UTC on September 23. Conditions were good this week, with sunspots visible every day -- and very little geomagnetic activity. The average daily sunspot numbers rose more than 24 points to 40 and the average daily solar flux was up nearly 5 points to 82.9. Solar flux was expected to rise to 88 for September 23-27, but instead it was 84.3 on September 23, and now the solar flux forecast for September 24-28 is 3 points lower, 85. For September 29-October 5, the solar flux forecast is 84, 82, 82, 82, 80, 78 and 76. Sunspot numbers for September 16-22 were 46, 41, 42, 50, 38, 37 and 26, with a mean of 40. The 10.7 cm flux was 82.5, 82.2, 82.1, 81.2, 82.6, 84.6 and 84.8, with a mean of 82.9. The estimated planetary A indices were 6, 8, 4, 4, 4, 6 and 2, with a mean of 3.7. The estimated mid-latitude A indices were 5, 7, 2, 2, 3, 5 and 1, with a mean of 2.9.

The planetary A index for September 24-30 is predicted to be 10, 7, 5, 5, 7, 8 and 5. Geophysical Institute Prague predicts quiet to unsettled conditions on September 24, quiet conditions September 25-27, quiet to unsettled September 28 and quiet again on September 29-30.

Bill Magruder, KD7KST, sent in an interesting link showing live aurora from Yellowknife in Canada’s Northwest Territories, which is at 62.433 degrees north latitude.  Check it out and have a look -- after dark, of course. This weekend, the Sun sets in Yellowknife around 0125 and sunrise is at 1334.

Alfio Bonanno, IT9EJW, in Italy operates a 10-meter beacon on 28.226 MHz. He reports that for the first time since the beacon was put on the air in 2008, it was heard outside Europe. LW3EX in Buenos Aires, Argentina copied it at 1647 on September 15.

WorldRadio online has a new monthly propagation column from Carl Luetzelschwab, K9LA, featuring his observations about the rise time for solar cycles compared to the current Solar Cycle 24.

Dave Ripton, K6SIX, of Morris Plains, New Jersey, commented about a recent question concerning TVI on 6 meters. Dave wrote: “In this week’s bulletin, you mentioned the improvement in 6 meter TVI. We have to thank the cable, satellite and fiber optics companies for the reduction in 6 meter TVI. In my Northern New Jersey area, roof top TV antennas are rare and the ones that are there are rusted-out, so I expect they are no longer used. With Channel 2 gone, even indoor ‘rabbit ears’ are no longer a problem. Also, telephone RFI has dropped, thanks to the new wireless phone bands. With all the new rigs that included 6meters, it is a great band for newcomers, as well as 6 meter nuts like myself. Now all we need is some F2 to really bring 6 meters back to life.”

John Ragle, W1ZI of Hadley, Massachusetts, wrote: “I run 350 W (peak) output on 50 MHz to a 5 element beam about 30 feet up, and about 50 or 60 feet from our house and a neighbor’s house. The TV and Internet cable come in on underground fiber optic, and across the street, underground as double-shielded coax. The run from the sill junction box on the house to the interior of the house is with ordinary single-shield coax. I also run about 350 W (peak) on 2 meters and 90 W on 70 cm, as well as 100 W on HF. There is not the slightest hint of TVI in either location, although my wife’s sound system (her computer sound card is hooked to an FM radio’s audio in) picks up some crackle from the modulation peaks in the 2 meter band.”

All times, unless otherwise noted, are UTC.



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 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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