HobbyKing

FRIDAY STORM EDITION: 50 MPH winds and torrential rain today, 4-6 inches. ....I will post news later, I had the grandkids over night and PT for my shoulder at 10AM.... A lot of radio amateurs may have been wondering, 'Where did the bands go?' as the first X-class solar flare in 4 years blacked out HF propagation for a time on July 3. 'Many American... radio amateurs reported sudden HF propagation blackouts on Saturday morning, July 3, when solar active region 12838 produced an X1.5 major solar flare that reached maximum intensity at 1429 UTC, the first X-class solar flare of Solar Cycle 25 and the first since 2017,' Frank Donovan, W3LPL, said. HF propagation blackouts are caused when x-ray and extreme ultraviolet radiation from X-class solar flares strongly ionizes the absorbing D-region in the Earths sun-facing dense lower ionosphere,' he explained. In this instance, it caused what NOAAs Space Weather Prediction Center ( SWPC ) calls an R3-level or strong radio blackout (on a scale of R1 R5). An R3 incident can cause a wide-area blackout of HF radio communication [and] loss of radio contact for about an hour on sunlit side of Earth. Low-frequency navigation signals degraded for about an hour. Donovan said that X-class major solar flares are necessary consequences of steadily increasing Solar Cycle 25 activity. 95% of all X-class solar flares occur when the solar flux index is 90 or greater. The remaining 5% can occur any time during the solar cycle, he points out. X1-class major solar flares typically degrade HF propagation for only an hour or two at mid and high latitudes, only on Earths sunlit side. X-class major flares are measured on an open-ended scale. The strongest one ever recorded was an X28 flare in 2003, hundreds of times more powerful than the July 3 X1.5 solar flare. X10-class and stronger solar flares typically have effects that last for most of a day and affect the entire sunlit side of the Earth. Fortunately, X10-class solar flares occur only about once every 20 years or more. Much more severe ...Read More