ARRL

Secure Site Login

News

The K7RA Solar Update

10/09/2020

Tad Cook, K7RA, Seattle, reports: Geomagnetic activity quieted down over the October 1 – 7 reporting week. Compared to the previous 7 days, average daily mid-latitude A index declined from 15.6 to 6, and average planetary A index slipped from 22 to 7.1.

There were no sunspots this week and only one in the previous 7. Average daily solar flux went from 73.4 to 71.8.

On late Thursday, October 8, however, two new Solar Cycle 25 sunspots appeared! They are both in the southern hemisphere, and, as of this writing, had not been assigned numbers.

Check Spaceweather.com later to see the official sunspot numbers. You can check here Friday night to see the daily sunspot numbers and daily total sunspot area over the last month. I just hope this activity isn’t like recent spots, which made only brief, faint appearances.

Predicted solar flux over the next 45 days is 72 on October 9 – 14; 70 on October 15 – 18; 72 on October 19 – 31; 70 on November 1 – 14, and 72 on November 15 – 22.

Predicted planetary A index is 5 on October 9 – 19; 10, 18, 20, and 24 on October 20 – 23; 16, 38, and 38 on October 24 – 26; 26, 15, and 10 on October 27 – 29; 5 on October 30 – November 6; 10 on November 7; 5 on November 8 – 15; 10, 18, 20, and 24 on November 16 – 19; 16 on November 20 – 21, and 38 on November 22.

F.K. Janda, OK1HH, provided this geomagnetic activity forecast for October 9 – November 4. He reports the geomagnetic field will be:

  • quiet on October 16, 18, November 2.

  • quiet to unsettled on October 9-10, 12-14, 17, 31, November 3-4.

  • quiet to active on October 15, 19-20, 28-29, (30,) November 1.

  • unsettled to active October 11, 21-24, 27.

  • active to disturbed October 25-26.

  • Solar wind will intensify on October 13, (14-15, 20-21,) 22, (23-24,) 25-29, (30,) November 2-4.

Note: Parentheses mean lower probability of activity enhancement.

Here’s word from NASA about a new look at sunspots:

Solar physicist Leif Svalgaard predicts a slightly better Solar Cycle 25.

Has the pandemic affected amateur radio activity? Yes, and in a good way.

All that isolation seems to allow more time on the air, if HF contest activity is any indicator.

From Jon, N0JK in Kansas:

Some weak sporadic-E from Kansas to Florida October 6 around 1900 UTC, but stations farther east had some outstanding propagation. Stations in Ecuador worked north to the Gulf Coast, then New England on 6 meters.

Propagation mode? F2 can occur in early October between North America and South America, but the solar flux was only 71 and with no major geomagnetic activity. Multi-hop sporadic-E may have been the mode. Some sporadic-E was spotted from New England to Florida, and Florida to Mexico. E-skip is rare in October, too.

HC2FG

20/10/06

2104Z

50313.0

 

still in FN44 Maine

K1TOL

HC3AP

20/10/06

2103Z

50314.4

FT8

 

W4AS

HC3AP

20/10/06

2100Z

50313.0

 

CQ

XE1MEX-#

HC1BI

20/10/06

2055Z

50313.0

 

73

KW4BY

HC1BI

20/10/06

2051Z

50314.2

FT8

 

KD5M

HC1BI

20/10/06

2046Z

50313.0

FT8

Maine

K1TOL

HC2FG

20/10/06

2046Z

50313.0

 

73

KW4BY

HC1BI

20/10/06

2045Z

50314.2

FT8

 

W4AS

HC2FG

20/10/06

2037Z

50313.0

FT8

Maine

K1TOL

HC2FG

20/10/06

2035Z

50313.0

 

 

WB2TQE

HC2FG

20/10/06

2033Z

50314.7

FT8

 

KD5M

Jeff Hartley, N8II writes from West Virginia:

“I just finished the California QSO Party. Saturday, 15 meters was very marginal; I made about 20 QSOs. Today, 15-meter conditions were excellent to all of California from 1640 – 1850 UTC, enabling me to work about 110 total 15-meter QSOs. 80 and 40 were excellent to California, with the 40-meter peak about 30 – 60 minutes before their sunset Saturday evening. Some signals on 80 were quite loud, and the California stations were hearing my 200 W very well. Also, signals were still good to California almost 2 hours after my sunrise today on 40. 20 was very poor 2200 – 2300Z Saturday, but improved enough for me to run 20-meter SSB stations 2300 – 2340Z. I noticed some possible sporadic E to central Tennessee and Kentucky in the afternoon on 20 (also some unexpected Illinois stations late morning).”

Tamitha Skov, WX6SWW explains the cause of recent geomagnetic activity.

Sunspot numbers for October 1 – 7 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. The 10.7-centimeter flux was 72.8, 72.2, 71.8, 71.2, 72.3, 71.7, and 70.7, with a mean of 71.8. Estimated planetary A indices were 11, 9, 6, 4, 8, 7, and 5, with a mean of 7.1. Middle latitude A index was 11, 6, 5, 3, 7, 6, and 4, with a mean of 6.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check out K9LA’s Propagation Page.

A propagation bulletin archive is available. Monthly charts are no longer be updated on this page. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Instructions for starting or ending email distribution of ARRL bulletins are on the ARRL website.

Share your reports and observations.



Back