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The K7RA Solar Update


Tad Cook, K7RA, Seattle, reports: Solar activity was lower this week, with the average daily sunspot number declining from 34.9 last week to 13.9 this week. This average was affected by the single day with no sunspots, Saturday, June 12.

Average daily solar flux dropped from 77.7 to 75.2. The Penticton observatory in British Columbia (the source for the 10.7-centimeter solar flux) did not report a noon reading on Wednesday, June 16, so we averaged the morning (76.9 at 1700 UTC) and afternoon readings (77.1 at 2300 UTC) to come up with 77 as a reasonable approximation.

Normally, the local noon reading (2000 UTC) is the official number for the day. You can get the three daily readings directly from the Dominion Astrophysical Observatory.

On Thursday, the noon flux reading was 85, higher than it’s been since May 26, when it was 88.

Predicted solar flux for the near term is 75 on June 18–20; 80 on June 21–25; 77 on June 26–28; 78 on June 29 – July 7; 79 on July 8–10; 77 on July 11–13; 76 on July 14–16; 78 on July 17; 80 on July 18–20; 78 on July 21, and 77 on July 22–25.

Predicted planetary A index is 12 on June 18; 5 on June 19–25; 7 on June 26; 5 on June 27 – July 4; 15, 10, and 8 on July 5–7; 5 on July 8; 8 on July 9–11; 10, 12, 20, and 12 on July 12–15; 5 on July 16–22, and 7 on July 23.

I am very excited about this forecast for the new Solar Cycle 25, which we are now seeing only its early stages. Forbes Magazine reported this.

Here’s the geomagnetic activity forecast for June 18 – July 15, from J.K. Janda, OK1HH:

The geomagnetic field will be:

  • quiet on June 20, 24, 27 – 28, July 1, 10, 15

  • quiet to unsettled on June 18 – 19, July 11, 14

  • quiet to active on June 21, 23, 25 – 26, 29 – 30, July 2, 6 – 9

  • unsettled to active (June 22, July 3 – 5, 12 – 13)

  • active to disturbed — nothing!

  • Solar wind will intensify on June (18 – 19,) 21, (22 – 24, 29,) 30, July (2,) 3, 5, 10 – 11

Remarks: Parentheses mean lower probability of activity enhancement.

F.K. Janda, OK1HH, of the Czech Propagation Interest Group, has been compiling this weekly geomagnetic activity forecast since January 1978.

Jeff, N8II, wrote: “On June 4 – 5, there was a very good 10 meter sporadic E opening to Europe, which started well before I did at 2200 UTC. Ian, MM0TFU, was the first one in the log on 10 SSB with 5/8 reports both ways. Andy, LZ2HM, was next on CW with a good signal; no other EU stations within 1000 kilometers were worked. Most all of my QSOs were with the UK and Ireland; I worked all four major UK DXCC entities. EI6JK and EI3EIB were both loud after 2400 UTC; last QSO was 0022 UTC with a total of about 20 EU contacts. Signal levels were very good from most stations.

“On June 11, 10 meters was open on Es to somewhere for most of the day. At 1900 UTC stations from Florida and the Gulf Coast were loud, including K4D on Dog Island IOTA NA-085 in the Big Bend area of the Gulf. Around 2000 UTC, I worked Missouri, Nebraska, and Michigan. Then at 2200 UTC 3 very loud VE3 stations from north-central Ontario. AC2CZ/VE2 in Montreal running 12 W into a dipole was next. Starting 2347 UTC I worked Kansas, Michigan, Minnesota, and Illinois before two double-hop Es contacts after 2400 UTC with N7WWH near the coast of north Oregon, and KM6YSS in Canyon County, Idaho. At 0027 UTC, XE1XR in central Mexico was S-9+ and easily worked, followed by Luis, XE2B, at 0036 UTC. All contacts were on SSB.

“The ARRL June VHF Contest took place June 12 – 14, which found some sporadic E most of the time. On 6 meters SSB and CW, I made 130 QSOs with my poor-performing Yagi. The Es started around 2230 UTC with stations in Tennessee, Texas, and northern Florida. Sunday morning, Es started with W0WP in Iowa (EN42) and spread to other WØs, followed by an intense opening to the south and southwest, with my closest contact being with Ed, K3DNE, in EM94 SC. Many Georgia stations were very loud, as were many in Florida and some in Texas and Oklahoma. I also caught Nova Scotia and Newfoundland. At 1546 UTC, I found EA8BPX in the Canary Islands (IL18) and was able to get through. In the afternoon many local stations on FT8 were working EU stations mostly in Spain, France, and Portugal. I worked F4ARU in France at 1834 UTC on SSB. Late around 0100 UTC, the band was still open well to EM19 (NQ0P as loud as a nearby local), EM49, and EM18.

“Today, June 17, there was an opening to Spain on 10 meters at 1950 UTC to EA7HZ and EA3AR. My noise level was very high. MM0TFU was reporting hearing beacons near my location and farther up the east coast at 2200 – 2300 UTC. At 0012 UTC on the June 18, I worked VP9KD in Bermuda who was S-9+ for a new band slot on 10 meters SSB.”

Sunspot numbers for June 10 – 16 were 29, 13, 0, 22, 11, 11, and 11, with a mean of 13.9. The 10.7-centimeter flux was 73.3, 77.3, 77.6, 68.9, 76.8, 75.5, and 77, with a mean of 75.2. Estimated planetary A indices were 5, 10, 10, 7, 4, 17, and 14, with a mean of 9.6. Middle latitude A index was 5, 11, 8, 7, 7, 15, and 15, with a mean of 9.7.

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. 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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