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The K7RA Solar Update

10/18/2019

Solar activity remains very low. At the bottom of the sunspot cycle, any sunspot activity is fleeting. Again, another week passes with no sunspots at all. Spaceweather.com reports no sunspots for the past two weeks, and the total number of spotless days this year is now 213 days, or 73%, matching the percentage of spotless days in 2008.

Average daily solar flux during the week of October 10-16 was 67.3, down insignificantly from 67.6 during the previous week.

Average daily planetary A index was 6.4, down from 14.4 in the previous week, and average daily mid-latitude A index declined from 11 to 5.1.

The predicted solar flux for the next 45 days is 66 on October 18-25, then 68 on October 26 through December 1.

Predicted planetary A index is 5 on October 18-20, then 12, 8, 5, 20, 25, 12, 10 and 8 on October 21-28, then 5 on October 29 to November 9, then 8 on November 10-11, then 5 on November 12-16, 15 on November 17, 5 on November 18-19, then 15, 20, 10 and 8 on November 20-23, and 5 on November 24-30.

Geomagnetic activity forecast for the period October 18 until November 12, 2019 from F.K. Janda, OK1HH.

Geomagnetic field will be:
Quiet on: October 29-30, November 8-9, 11-12
Quiet to unsettled on: October 18-20, 22-23, November 4-5, 7, 10
Quiet to active on: October 28, 31, November 2-3
Unsettled to active on: October 21, 27, November 1, 6
Active to disturbed: October (24-) 25 (-26)

Solar wind will intensify on: October 11 (-14, 21-23. 25), 26, November 7-9

Parenthesis means lower probability of activity enhancement.
The predictability of changes remains lower again.

Rick Tucker, W0RT, of Parsons, Kansas was listening for HZ1TT (Saudi Arabia) on October 14 on 21.023 MHz at 1045 UTC. The band sounded dead, but at 1115 UTC he copied 8 or 10 European stations calling and working the Saudi station. Rick said he never heard HZ1TT, but HZ1TT was spotted by a VE9.

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 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. More good information and tutorials on propagation are at http://k9la.us/.

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 October 10 through 16, 2019 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 67.5, 68.5, 68.3, 67.2, 66.2, 67.2, and 66.3, with a mean of 67.3. Estimated planetary A indices were 13, 8, 5, 2, 6, 5, and 6, with a mean of 6.4. Middle latitude A index was 10, 6, 4, 1, 5, 5, and 5, with a mean of 5.1.

 



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