ARLP046 Propagation de K7RA


Here’s the latest Amateur Radio Propagation Forecast from Tad Cook (K7RA).

Views expressed in this propagation update are those of the reporters and correspondents.

Accessed on 13 November 2021, 1440 UTC.

Content provided by Tad Cook (K7RA), W1AW, and HQ ARRL.


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ARRL Propagation Bulletin ARLP046 (2021)

SB PROP @ ARL $ARLP046 ARLP046 Propagation de K7RA ZCZC AP46 QST de W1AW Propagation Forecast Bulletin 46 ARLP046 From Tad Cook, K7RA Seattle, WA November 12, 2021 To all radio amateurs SB PROP ARL ARLP046 ARLP046 Propagation de K7RA Sunspot activity and solar flux dropped this reporting week (November 4-10), with the average daily sunspot number retreating from 67.6 to 36.4, and solar flux from 102 to 89.1. Geomagnetic indicators rose, average daily planetary A index from 12 to 18, and middle latitude values from 9 to 11.7. When the planetary and middle latitude A index were 69 and 42 on November 4, Alaska’s College A index was a whopping 131. College K index peaked at 9 on that day. K index is logarithmic, so each point in the scale represents a big difference in activity. The A index is linear, and based upon the K index. The K index is reported every three hours, and the College K index on November 4 was 5, 5, 8, 9, 8, 5, 3 and 2. This was all caused by what called a “Cannibal CME,” because it was a CME overtaken by a second larger and faster moving coronal mass ejection. At 1701 UTC on November 9 a CME eruption just over the Sun’s western horizon emitted enough energy to cause a shortwave radio blackout, which is pictured here: Predicted solar flux is 86 on November 12, 85 on November 13-16, 84 on November 17, 83 on November 18-19, 90 on November 20, 95 on November 21-27, 90 on November 28-29, 85 on November 30 through December 2, 82 on December 3-4, 85 on December 5, 82 again on December 6-9, 80 on December 10-11, 85 on December 12, and 87 on December 13-15. Flux values may peak at around 95 on December 18-24. Predicted planetary A index is 5 on November 12-15, 8 on November 16-17, 5 on November 18-27, then 10, 10 and 8 on November 28-30, 5 on December 1-4, 8 on December 5, 5 on December 6-9, then 7, 7, 10 and 8 on December 10-13, and 5 on December 14-24. F. K. Janda, OK1HH presents his geomagnetic activity forecast for the period November 12 to December 1, 2021. “Geomagnetic field will be: quiet on: 18-19, 23, 25, quiet to unsettled on: November 12-13, 17, 20, 22, 24, quiet to active on: November 21, 26-27, unsettled to active on: November 14, 16, 28, Active to disturbed: November (15, 29,) 30, December 1, “Solar wind will intensify on November 16-17, (29-30), December (1-2,) 3-4. “Parenthesis means lower probability of activity enhancement.” Don’t know why I had not noticed this before: Unfortunately, only one of the two spacecraft remains, but it is still a very useful tool: N0JK wrote from Kansas: “Good conditions on 17 meters Sunday afternoon November 7. I found the HD8R Galapagos Island DXpedition on 18.147 MHz SSB loud with few callers. Was able to work them easily with 5 watts and mobile whip at 2022 UTC. Sometimes a DXpedition is easier to work on the WARC bands.” Early on November 12, reported all is quiet for now. “Space weather near Earth is calm, but the Sun is not quiet. This week, SOHO coronagraphs have observed multiple CMEs billowing over the western edge of the Sun. The source is a farside sunspot group, probably the same one that produced a strong M2-class solar flare on November 9th. Earth is not in the line of fire, for now.” Another great video report from Dr. Tamitha Skov, WX6SWW, the Space Weather Woman: If you would like to make a comment or have a tip for our readers, please email the author at, . For more information concerning shortwave radio propagation, see and the ARRL Technical Information Service web page at, For an explanation of numbers used in this bulletin, see An archive of past propagation bulletins is at More good information and tutorials on propagation are at Instructions for starting or ending email distribution of ARRL bulletins are at . Sunspot numbers for November 4 through 10, 2021 were 28, 40, 41, 28, 41, 40, and 37, with a mean of 36.4. 10.7 cm flux was 93.8, 92.8, 82.1, 87.5, 88.3, 92, and 87.5, with a mean of 89.1. Estimated planetary A indices were 69, 13, 18, 6, 5, 7, and 8, with a mean of 18. Middle latitude A index was 42, 9, 13, 4, 3, 6, and 5, with a mean of 11.7. NNNN /EX
Aloha es 73 de Russell Roberts (KH6JRM)

Public Information Officer

Hawaii County, ARRL Pacific Section


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