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The K7RA Solar Update


Tad Cook, K7RA, Seattle, reports: It’s exciting to observe increasing sunspot activity. Recently Solar Cycle 25 produced new sunspots frequently, and I watch them pop up every day on New sunspots emerged on July 14, 16, 17, 19 and 20, and two new ones appeared on July 21. When I look at this image from July 22, our sun is peppered with spots, reminding me of past solar cycles.

Average daily sunspot numbers more than doubled from 21.3 last week to 48.9 during this reporting week, July 15-21. Average daily solar flux jumped from 72.9 to 81.3.

Geomagnetic numbers held steady, with both the middle latitude and planetary A index averages at 6.4.

Predicted solar flux is 89 and 87 on July 23 – 24; 85 on July 25 – 30; 90 on July 31 – August 1; 85 on August 2; 75 on August 3 – 12; 78, 80, and 80 on August 13 – 15; 85 on August 16 – 21, and 90 on August 22 – 28.

Predicted planetary A index is 18, 16, and 8 on July 23 – 25; 5 on July 26 – 27; 8 on July 28; 5 on July 29 – August 1; 8 on August 2; 5 on August 3 – 9; 12 and 10 on August 10 – 11; 5 on August 12 – 16; 8 on August 17 – 18; 5 on August 19 – 28, and 8 on August 29.

F.K. Janda, OK1HH, sent this geomagnetic activity forecast for July 23 – August 19, before he takes a week of vacation.

The geomagnetic field will be:

  • quiet on: July 25, 30, August 7, 12 – 13

  • quiet to unsettled on: July 24, 28 – 29, 31, August 9, 14

  • quiet to active on: July 23, 26, August 1, 3 – 6, 11, 15 – 17, 19

  • unsettled to active: July 27, August 2, 8, 10, 18

  • active to disturbed: None predicted!


=Parenthesis means lower probability of activity enhancement.

=Next Thursday, I will not compile a forecast of Earth’s magnetic field activity, because I will be walking on the highest mountains of my country — the Krkonoše Mountains — without such conveniences of civilization as computer or internet. But I will have a good friends, camera and binoculars with me!

OH6BG has some interesting VOACAP links on his profile.

I’ve been having fun using remote SDR receivers to hunt for 10-meter beacons during the day. This revealed much more sporadic-e propagation than I was previously aware of.

On Thursday, using the AB9MQ receiver in Normal, Illinois, I copied beacons KE5JXC/b in Kaplan, Louisiana, on 28.2515 MHz; WD8INF/b in Lebanon, Ohio, on 28.2525 MHz, and KC5SQD/b in Missouri City, Texas, on 28.2508 MHz.

You will notice on the 10-meter beacon roster from WJ5O that the listings resolve to 100 Hz, instead of 1 KHz. This allows more of them to be packed together on the band. The three beacons mentioned here were all copied with the receiver tuned to the same frequency, and because they transmit on slightly different frequencies, they’re easy to copy.

A correction: I mentioned my new CW beacon, K7RA/b on 28.2833 MHz in last week’s report. The power output is actually 11 W, as I was reminded by UY5DJ/AA7DJ who generously built the beacon transmitter and controller.

N8II in West Virginia, wrote:

“There was much intense sporadic-e, mostly within the US and Canada on July 13-15 with double hop to MT, UT, WA, OR, BC, CA, NV and AZ.

“Several times the skip zone shortened to stations less than 300 miles away in NC, SC, KY, and OH. I easily made over 100 QSOs. I worked Steve, VE2CSI, in Sept-Iles, Quebec (FO60), a couple of times on 10 meters and once on 6 meters, all SSB.

“Things were fairly quiet until July 18, when Europe came through well on 10 starting just after 1200 UTC, working 9A2U, Croatia, and Vlada, YU4VLA, Serbia, along with Italy, Bulgaria, Switzerland, Belgium, Scotland, and several German stations until 1319 UTC.

“Just after 0000 UTC on the July 19, 10 meters came alive with SSB activity from Maine and the US 4th area. I found TI5KMK in Costa Rica, probably via Es, and also Puerto Rico. Suddenly on July 21, Upstate New York and New England stations with big signals appeared, starting 2214 UTC. French stations F6ARC and F4AIF were found around 2240 UTC.

“July 22 saw one of the best openings of the year to western Europe on 10 meter. I ran quite a few stations on 28.430 MHz SSB after calling EI2IP and EI3GD in Ireland starting at 1941 UTC. Signal levels were very good, and many stations were active. The highlight was being called by SE5S and Hawk, SM5AQD, both in Sweden. SM5AQD was peaking S-9 running 1,500 W to a triple stack of eight-element tri-band Yagis. Soon after, MM0TFU in Scotland called in with a bit better signal. As I recall, he runs 400 W into a three-element Yagi. This was the loudest Ian has been this year after several 10-meter QSOs. Around 0040 UTC, I worked WA2OOO on Long Island, New York, less than 300 miles away, with a strong signal, as well as VO1VXC in Newfoundland.”

Here’s the latest video (July 17) from Space Weather Woman Tamitha Skov, WX6SWW.

Sunspot numbers for July 15 – 21 were 22, 35, 53, 42, 45, 59, and 86, with a mean of 48.9. The 10.7-centimeter flux was 73.5, 75, 77.4, 80.4, 82.6, 87, and 93.5, with a mean of 81.3.. Estimated planetary A indices were 10, 4, 4, 4, 7, 10, and 6, with a mean of 6.4. Middle latitude A index was 12, 5, 4, 5, 4, 9, and 6, with a mean of 6.4.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check out this propagation page.

A propagation bulletin archive is available. 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.



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