SB PROP @ ARL $ARLP038 ARLP038 Propagation de K7RA ZCZC AP38 QST de W1AW Propagation Forecast Bulletin 38 ARLP038 From Tad Cook, K7RA Seattle, WA September 24, 2010 To all radio amateurs SB PROP ARL ARLP038 ARLP038 Propagation de K7RA 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. Average daily sunspot numbers rose more than 24 points to 40, and average daily solar flux was up nearly five 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 forecast for September 24-28 is solar flux three points lower, 85. For September 29-October 5 the solar flux forecast is 84, 82, 82, 82, 80, 78 and 76. 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. Go to http://snipurl.com/15tszs and have a look, after dark, of course. This weekend sun sets in Yellowknife around 0125z and sunrise is at 1334z. 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 1647z on September 15. Information on the beacon is at http://www.it9ejw.it/beacon.htm. WorldRadio online has a new monthly propagation column from Carl Luetzelschwab, K9LA, this time with his observations about the rise time for solar cycles compared to the current cycle 24. You can find it at http://www.worldradiomagazine.com/. Dave Ripton, K6SIX of Morris Plains, New Jersey commented about a recent question concerning TVI on six meters. Dave wrote, "In this week's bulletin you mentioned the improvement in 6M TVI. We have to thank the cable, satellite, and fiber optics companies for the reduction in 6M TVI. In my Northern NJ 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 6M it is a great band for newcomers as well as 6M nuts like myself. Now all we need is some F2 to really bring 6M's back to life". John Ragle, W1ZI of Hadley, Massachusetts wrote "I run 350 watts (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 cross 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 watts (peak) on 2 meters and 90 watts on 70 cm, as well as 100 watts 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". If you would like to make a comment or have a tip for our readers, email the author at, k7ra@arrl.net. For more information concerning radio propagation, see the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of the numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. Find more good information and tutorials on propagation at http://mysite.ncnetwork.net/k9la/index.html. Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation. Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins. Sunspot numbers for September 16 through 22 were 46, 41, 42, 50, 38, 37, and 26 with a mean of 40. 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. Estimated planetary A indices were 6, 8, 4, 4, 4, 6 and 2 with a mean of 3.7. Estimated mid-latitude A indices were 5, 7, 2, 2, 3, 5 and 1 with a mean of 2.9. NNNN /EX