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The K7RA Solar Update


Tad Cook, K7RA, Seattle, reports: Solar activity continues to increase. In last week’s bulletin ARLP027 average daily sunspot number was 34.7. This week it jumped to 55.6. Average daily solar flux increased from 86.9 to 88.9.

Despite solar flare activity pushing a sudden ionospheric disturbance and a dramatic HF radio blackout (on July 3), the average daily planetary A index for the week was only 5.7, down from 6.1 last week. The average middle latitude A index was also 6.1 last week, and it was 6.3 this week.

The July 3 flare was an X1.5-class event, the biggest since September 2017 and the only X-Class solar flare since then. It got readers wondering what was up.

Scott Craig, WA4TTK, wrote, “What happened about 1430 UTC on July 3? Some people on a forum are saying it was a massive solar flare. I was on 20 meter FT8 and my waterfall display went from solid red signals to solid nothing in the blink of an eye. It lasted about 10 minutes.”

Events such as this can be so dramatic that many may assume a hardware or antenna failure. Fortunately, these are rare.

W3LPL developed an excellent narrative on this event. See “First X-Class Major Solar Flare of Solar Cycle 25 Blacks Out HF on July 3.”

The event received some coverage outside the usual channels, including Market Research Telecast (MRT), IFLScience, and CNN.

Also, Tamitha Skov, WX6SWW, our Space Weather Woman covered this in her July 6 edition of “Space Weather News.” Love her enthusiasm, as well as her solid science reporting.

Predicted solar flux is 73 on July 9 – 13; 72 on July 12 – 13; 72 on July 14 – 15; 76 on July 16; 82 on July 17 – 18; 84 on July 19; 88 on July 20 – 22; 90 on July 23 – 28; 88 on July 29 – August 2; 84 on August 3; 82 on August 4 – 5; 80 on August 6 – 11, and 82 on August 12 – 14.

Predicted planetary A index is 5 on July 9 – 10; 8, 12, 16, 12, and 8 on July 11 – 15; 5 on July 16 – 17; 15, 12, and 10 on July 18 – 20; 5 on July 21 – 31; 10 and 8 on August 1 – 2; 5 on August 3 – 5, 15 and 12 on August 6 – 7, and 5 on August 8 – 13.

Here’s the geomagnetic activity forecast for July 9 – August 5 from Frantisek K. Janda, OK1HH, of the Czech Propagation Interest Group. He has been compiling this geomagnetic activity weekly forecast since January 1978.

The geomagnetic field will be:

  • quiet on July 14, 16-18, 21, 23-25, 28, 30-31, August 3-5

  • quiet to unsettled on July 9-10, 15, 22, 29, August 1-2

  • quiet to active on July 11, 13, 19-20, 26-27

  • unsettled to active July 12

  • active to disturbed none predicted

Parenthesis means lower probability of activity enhancement.”

Bob McHenry, G3NSM wrote:

“On July 5, I was amazed to work KL7HBK at 1447 UTC on 50.323 MHz FT8. John is in Anchor Point, BO49, which is just south of Anchorage and I was beaming on the short path, 345°. It wasn’t a marginal contact. John was in for 10 minutes and gave me a report of +05, which suggests he might have heard me on CW. I believe John also worked into [Europe] on the same day. He confirmed the contact with me on LoTW the next day.

“Contacts between Alaska and Europe on 6 meters are very rare, and John was the only signal coming through from that region. There were no W6, W7, or VE7 stations audible as there had been on the previous day.”

Thanks, Bob. I will check for any reports from July 4.

Jeff Hartley, N8II, in West Virginia wrote:

“Between increased SFI and plentiful sporadic E it was a fun week on the bands.

“The RAC Canada Day contest July 1 started with a good evening opening on 40 to all nearby areas of Canada. I worked about 65 stations in Ontario and Quebec, mostly on SSB. Sunday morning around 1400 – 1845 UTC, there was very intense sporadic E into all provinces from Ontario east to Newfoundland on all bands, including 10 meters. Normally Ontario is skipping over me on 20. I worked nine provinces on 15 CW, 10 on SSB, 8 on 10 CW, 9 on SSB! Even Labrador was worked on 15 SSB. The highlight was a run of five British Columbia stations on 10 meters CW at 1700. VE1 – VE9 except VE8 and VY2 Prince Edward Island were all logged on 10 SSB.

“On July 2 starting 1340 UTC, I worked three English stations and PA1CC in the Netherlands on 10-meter Es. TM13COL, a special French call sign for the 13 Colonies on the Air event, was worked on 12 CW with a strong signal. Then, at 1455 UTC, amid many New England QSOs on 10, I worked two Italian stations and MM0TFU in Scotland. At 1533UTC I found LY4A Lithuania (new band slot) on 10 SSB and Germany.

“17M was open late at 2340 UTC to Poland and S9 EI3GIB in Ireland on the July 3. On the July 4 at 2048 UTC, HB90BERO in Switzerland was S-9 on 15 SSB. I heard two Lebanese stations as well, with OD5ZZ peaking S-6, but no QSOs. At 2017, SO1WS Western Sahara was logged on 17 SSB, followed by V73NS in the Marshall Islands on 17 CW who was working Denmark and Portugal over the North Pole. At 2200 UTC, 17 was still wide open working Switzerland, Russia, Slovenia, the Dominican Republic, and England. G3YPZ moved up to 15 where he was S-5 on SSB followed by S-9+ IK4GRO in Italy. On the July 5 at 2212 on 15 CW KH0W in the Mariana Islands was weak over a tough path from here, and CT3MD Madeira was S-9+. On the July 6 at 1750 UTC, SP9FMP was marginally worked on 10 CW. ZA1E in Albania was a weak Q5, and stations very close to him in Europe were heard working him for about 15 minutes.”

The ARRL Contest Update reported, on July 7:

“Six meters has been exciting over the last week or so, with reports of excellent intercontinental propagation. US hams have been enjoying many contacts with Asia and the EU. Craig, K9CT, worked a few new ones on July 2: ‘Six meters was amazing today! DXCC total for 6 went from 128 to 141!’ The Pacific Northwest has even been getting in on some of the action, with some stations reporting new countries worked on 6 even with antennas like ‘a 20 meter dipole with an antenna tuner.’ You can’t work them if you don’t try!”

Sunspot numbers for July 1 – 7 were 56, 72, 81, 60, 43, 52, and 25, with a mean of 55.6. The 10.7-centimeter flux was 94.1, 94.9, 93.7, 91.1, 89.4, 83.2, and 76, with a mean of 88.9. Estimated planetary A indices were 7, 5, 4, 3, 7, 8, and 6, with a mean of 5.7. Middle latitude A index was 7, 6, 4, 4, 9, 8, and 6, with a mean of 6.3.

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.

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