Average daily sunspot numbers for the recent reporting week (August 3-9) rose 7.1 points to 12.1, and average daily solar flux rose from 71 to 73.2.

Average daily planetary A index went from 5 to 11.3, and mid latitude A index rose from 6 to 10.9.

Predicted solar flux for the near term is 74 on August 15-21, 72 on August 22, 68 on August 23-28, 70 on August 29, and 72 on August 30 through September 8.

Predicted planetary A index is 5, 16, 26 and 20 on August 15-18, then 16, 14, 12, 10 and 6 on August 19-23, 5 on August 24-29, then 12, 24, 18 and 14 on August 30 through September 2, and 5 on September 3-8.


W7WKR sent this: http://nyti.ms/2f4mpNH

Max White sent this: http://bit.ly/2uUxsNm

Ward Silver, N0AX, and others reminded me that the upcoming HamSCI experiment this month in conjunction with the solar eclipse is not actually sponsored by the ARRL, but is a creation of HamSCI, Ham Radio Science Investigation. Check them out at http://www.hamsci.org/ .


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 August 3-9, 2017 were 13, 13, 13, 13, 11, 11, and 11, with a mean of 5. 10.7 cm flux was 75.1, 74.1, 74.1, 73.5, 72.7, 71.1, and 71.5, with a mean of 71. Estimated planetary A indices were 12, 23, 16, 13, 5, 5, and 5, with a mean of 5. Estimated mid-latitude A indices were 11, 19, 17, 13, 6, 5, and 5, with a mean of 6.