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 Previous: ARRL Board of Directors Outlines Ambitious Legislative Agenda |  Next: Surfin': CW on the High Seas |
SEATTLE, WA, Jan 28, 2005--Solar activity was down this week. Average daily sunspot numbers were off by nearly 36 points to 53.4, and average daily solar flux dropped 31 points to 101.7.
On Friday, January 21, we were hit by a big blast of energy from an X7-class solar flare the previous day. The planetary A index went to 61, and the mid-latitude A index was 30. A severe geomagnetic storm lasted the next couple of days, but conditions really calmed down on Monday through Thursday, January 24-27. On Wednesday, January 26, the mid-latitude A index went clear down to zero because the K index, upon which it is based, was zero during all eight reporting periods. This is incredibly quiet--good for HF propagation, provided the sunspots are there to support it.
We could hope for similar quiet conditions for this weekend's CQ World Wide 160-meter CW Contest, but the forecast doesn't look that great. The predicted planetary A indices for Friday through Monday, January 28-31, are 15, 30, 20 and 20. This isn't due to any flare activity, but Earth is about to move into a solar wind stream, and the most active conditions are expected on January 29. Conditions should be back to quiet by February 3.
Ken Kopp, KK0HF, of Topeka, Kansas, shared a great article on recent solar activity that appeared in the Baltimore Sun. It is full of dramatic descriptions of solar flares and the recent giant sunspot. It also told how the International Space Station crew hunkered down in the better-shielded Russian Zvezda service module for the duration. Also be sure to check out a constantly updated collection of links to press clippings relating to Amateur Radio on KK0HF's Web site.
Flares, solar wind and geomagnetic storms aren't bad for all radio propagation. Six meters often gets interesting during active conditions, and a number of reports arrived this week concerning VHF. When HF operators thought their radios were dead on January 21, OZ1DJJ in Denmark worked Lefty Clement, K1TOL, in Maine on 6-meter CW via aurora during the Scandinavian Activity Contest. You can hear the QSO on OZ1DJJ's Web site. (Thanks to Arne, SM7AED, for passing along this info.
Jon Jones, N0JK, reported a nice 6-meter opening between Arizona and the Midwest on January 21 beginning at 0015 UTC and lasting nearly four hours. He was mobile in Wichita, Kansas, and worked K7TOP. K7NN in Tucson, and AC7XP and K7TOP in Phoenix worked stations in Kansas, Missouri, Oklahoma, Texas and Tennessee with strong signals.
And finally, ever thought of building your own magnetometer? I've thought for a long time that in addition to noting the College K index, Boulder K index or planetary K index, it would be neat to have one that is strictly local. Where I live in Seattle, I could have a University District K index, although in the city it might be affected by passing trucks. There's an article about a two-pole magnetometer on the Web. The same site offers real-time results from a homebrew magnetometer in the Netherlands.
For more information concerning propagation and an explanation of the numbers used in this bulletin see the ARRL Technical Information Service Propagation page.
Sunspot numbers for January 20 through 26 were 61, 69, 60, 40, 42, 56 and 46, with a mean of 53.4. The 10.7 cm flux was 122.7, 113.5, 102.2, 95.8, 94.6, 94.1 and 89.3, with a mean of 101.7. Estimated planetary A indices were 12, 61, 28, 17, 6, 4 and 4, with a mean of 18.9. Estimated mid-latitude A indices were 10, 30, 23, 12, 5, 2 and 0, with a mean of 11.7.
Amateur
solar observer Tad Cook, K7RA, Seattle, Washington, provides this weekly report
on solar conditions and propagation. This report also is available via W1AW
every Frida,y and an abbreviated version also appears in The ARRL Letter. Readers may contact
the author via e-mail.
| Previous: ARRL Board of Directors Outlines Ambitious Legislative Agenda | Next: Surfin': CW on the High Seas |
