Propagation de K7RA
10 August 2019A new sunspot group appeared only briefly this week, on August 7 and 8. It was sunspot 2747, from current cycle 24. Sunspot numbers on Monday and Tuesday were 11 and 12.
Average daily solar flux shifted only slightly from last week, from 67 to 67.2. Average planetary A index, a geomagnetic indicator aggregated from magnetometers around the world, more than doubled, from 5 to 10.3.
This was due to solar wind which raised the planetary A index to 35 on Monday. Alaska's high latitude college A index reached 61 on Monday and 24 on Tuesday.
Predicted solar flux is 68 on August 9 to 16 and 67 on August 17 through September 22. Predicted planetary A index is 5 on August 9, then 8 on August 10 and 11, 5 on August 12 to 16, 8 on August 17 and 18, 5 on August 19 to 25, 8 on August 26 to 28, 5 on August 29 and 30, then 12, 25, 25, 16 and 8 on August 31 through September 4, then 5, 8 and 8 on September 5 to 7, 5 on September 8 to 12, 8 on September 13 and 14, then 5 on September 15 to 21 and 8 on September 22.
OK1HH sent his geomagnetic activity forecast for the period August 9 to September 4, 2019, a day early this week. There will be no forecast from him next week.
"Geomagnetic field will be
Quiet on: August 12, 16, 21, September 4 Quiet to unsettled on: August 9, 13 to 15, 17, 22, 29 and 30, September 3 Quiet to active on: August 10 (- 11,) 19 and 20, 23 to 25, 28, 31 Unsettled to active on: August (18, 26 to 28), September 1, (-2) Active to disturbed- none
Solar wind will intensify on: August (9 to 14,) 27 to 29, (30 and 31, September 1 and 2)
- Parenthesis means lower probability of activity enhancement.
- Next forecast will be issued on August 22"
Dr. Tamitha Skov, WX6SWW posted a new 3-hour (!) long space weather mini-course a few days ago:
https://youtu.be/56oVhXD7AZE
Here is her report from August 8
https://youtu.be/a3hiGPOHZ-U
Tamitha will be one of the speakers this Saturday at the Pacific Northwest DX Convention, along with Joe Taylor, K1JT:
https://pacificnwdxconvention.com/
Mark, K4SO in Virginia wrote on August 8:
"My friend and neighbor, K1HTV, suggested I drop you a note about a brief, surprising opening on 10M this morning.
I had my small tribander (A3S) almost due north, and decided to drop down from 6M to 10M, on the way down to more 'active bands.' JTDX was running, as usual, when I got a JTAlert audio message 'DX' and looked to find a decode of RV0AR, calling CQ SA. I assumed it was a broken decode of some noise, but the next cycle it changed to CQ NA.
I started calling with 100W, and turned on my Alpha 89, which features 'the longest 3 minutes in ham radio' while the filaments warm up.
I used JTAlert's text function to encourage to ask him to keep calling, but no indication he was online. That is, by the way, an underutilized service. Anyway, luckily for me, his signal continued to build as the tubes warmed up.
I wondered if he was telling his local ham friends, 'Hey I just worked NA.' (in Russian of course, hi.)"
Mike, KA3JAW likes to monitor various VHF services, such as FM broadcast, for sporadic-e. He forwarded a report from William Hepburn in Grimsby, Ontario Canada who monitored over 45 minutes of e-skip from 162 MHz weather radio broadcasts from eight stations in Kansas, Arkansas, Colorado and Oklahoma from 2:19 PM to 3:06 PM local time back on July 20. Distances ranged from 839 to 1,253 miles.
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 August 1 through 7, 2019 were 0, 0, 0, 0, 12, 11, and 0, with a mean of 3.3. 10.7 cm flux was 66.8, 66.9, 65.7, 66.9, 68.1, 68.1, and 68, with a mean of 67.2. Estimated planetary A indices were 8, 4, 3, 4, 35, 12, and 6 with a mean of 10.3.
Middle latitude A index was 8, 4, 4, 6, 20, 10, and 6, with a mean of 8.3.
• All propagation reports can be found at:
http://www.southgatearc.org/propagation
