The K7RA Solar Update

Like June 24-27, July 7 had a new spot from cycle 25, according to the magnetic signature. This week’s brief appearance was last Sunday with a daily sunspot number of 12.

Average daily solar flux declined marginally from 67.5 to 67.1.

Predicted solar flux for the next 45 days is 67 on July 12 through August 25. That’s right, 67 on every day.

Predicted planetary A index is 8 on July 12, 5 on July 13-15, then 12 and 8 on July 16-17, 5 on July 18-27, 8 on July 28, 5 on July 29 through August 4, then 12, 15 and 12 on August 5-7, 5 on August 8-23, 8 on August 24 and 5 on August 25.


Interesting article on space weather: https://bit.ly/2G7Oz5g


A recent video from Tamitha Skov: https://youtu.be/q066gUaSsAU


OK1HH is taking a week off from his geomagnetic forecast and will return next week.


On Thursday night ,as I put this bulletin to bed, I am enjoying monitoring remote receivers around the world, via https://sdr.hu/?q=kiwisdr. I am currently listening to European CW traffic on 40 meters from a receiver in Ukraine.


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 July 4 through 10, 2019 were 0, 0, 0, 12, 0, 0, and 0, with a mean of 1.7. 10.7 cm flux was 67.8, 67.5, 66.5, 67.3, 66.5, 66.8, and 67.6, with a mean of 67.1. Estimated planetary A indices were 5, 5, 3, 5, 9, 17, and 15, with a mean of 8.4. Middle latitude A index was 8, 6, 5, 5, 7, 16, and 13, with a mean of 8.6.