ARRL

Secure Site Login

News

The K7RA Solar Update

09/27/2019

Sorry, still no sunspots. Spaceweather.com reported on September 26 there were no sunspots for over 3 weeks, or 24 consecutive days.

Summer transitioned through the autumnal equinox last Monday, and spaceweather.com noted that during the northern summer more than 89% of the days were spotless.

So far in 2019 the spotless days percentage is 72%, equal to what it was in the last solar minimum, in 2008 and 2009.

Passing the equinox is a good time for HF propagation, even with low solar activity, and this is true whether you are now in spring in the Southern Hemisphere or fall in the northern.

Over the past week (September 19-25) average daily solar flux shifted marginally from 68.1 to 67.3, while average daily planetary A index reflected quiet geomagnetic indices changing from 8.3 to 5.4 and mid-latitude indices went from 8 to 4.6.

Predicted solar flux is 67 on September 27 to October 4, and 68 on October 5 through November 10.

Predicted planetary A index is 28, 45, and 20 on September 27-29, 12 on September 30 and October 1, 8 on October 2-3, 5 on October 4-5, 12 on October 6, 5 on October 7-9, then 8, 5, 8, 10, 8 and 8 on October 10-15, then 5 on October 16-19, then 12 and 8 on October 20-21, 5 on October 22-24, then 25, 18, 10, 5 and 8 on October 25-29, then 5 on October 30 through November 1, 10 on November 2, 5 on November 3-5, then 8, 5, 8, 10 and 8 on November 6-10.

The planetary A index forecast of 28, 45 and 20 on September 27-29 is due to solar wind spewing from a large coronal hole. This is the same hole that gave us the planetary A index of 38 and 45 on August 31 and September 1. Look for it again on October 25-26 after yet another trip around the Sun.

 

Spaceweather.com reported in an email on September 26: GEOMAGNETIC STORM WARNING: A large hole in the Sun's atmosphere is facing Earth and spewing a stream of solar wind in our direction. NOAA forecasters say there is a chance of moderately-strong G2-class geomagnetic storms when the gaseous material arrives on Sept. 28th. The last such storm in early September produced auroras visible in many northern-tier US states. Visit today's edition of Spaceweather.com for more information and forecasts.

Geomagnetic activity forecast for the period September 27 until October 22, 2019 from F.K. Janda, OK1HH.

Geomagnetic field will be
Quiet on: October 8, 16-17
Quiet to unsettled on: October 3-4, 7, 9, 20
Quiet to active on: October 1-2, 6, 10-11, 15, 18-19, 22
Unsettled to active on: September 30, October (5, 12-14,) 21
Active to disturbed: September 27-28, (29)

Solar wind will intensify on: September 27-30, October 1 (-4, 7-9,) 11 (-14,) 21-23

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

Thanks to this week’s ARRL Letter for these two references to a 1921 disturbance I had never heard of, rivaling the infamous Carrington Event of 1859: https://bit.ly/2lyoDZB and https://bit.ly/2lvwpDo

Bil Paul, KDJUI, who operates ham radio from a kayak (detailed in November 2016 QST) reported on September 26: "I was operating from kayak today (Thursday) running 10 W into an end-fed half-wave wire vertical antenna alongside the boat in Lake Solano near Winters, CA. I was surprised to contact two French CW stations on 20 meters around noon Pacific Time (1900 UTC). They gave me signal reports of 5/3 and 5/5. I gave them S6 and S7 reports. There was a little fading.

“I did hear one station on 17 meters (CW), but no luck there. No luck either on 30 meters. Good fishing, though!"

 

N4SO in Alabama reports FT8 contacts on 40 and 17 meters on September 22-24: "Conditions have been favorable on 40 meters for making contacts with FT8 mode to Australia and New Zealand every night after midnight. Here are decoding examples from September 24 between 1 and 4 AM local time:

065715 -13  0.2 1281 -  CQ ZL4DC RE54      New Zealand
071915 -14  0.5 1692 -  CQ VK2FAD QF56     Australia
080800 -19  0.4  860 -  CQ VK7NET QE38     Australia
094830 -17  0.4  599 -  CQ SA VK6IR OF77   Australia

“Australia is also available with FT8 on 17 meters in the early evening hours before sunset. This one is even earlier at 4:40 PM Central Time.

214245 -12 -0.1 1776 -  N4SO VK2DX 73”


Here is the latest video from WX6SWW: https://youtu.be/rScJxk44OZE

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 September 19 through 25, 2019 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 67.1, 67.2, 67.7, 68.3, 66.1, 67.1, and 67.5, with a mean of 67.3. Estimated planetary A indices were 4, 3, 7, 4, 3, 13, and 4, with a mean of 5.4. Middle latitude A index was 4, 3, 7, 2, 2, 11, and 3, with a mean of 4.6.

 



Back