The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: The last time we experienced a day with no sunspots was October 13. Prior to that, September 26 – October 8, September 24, and August 21 – September 22 had no sunspots. Cycle 25 is clearly under way and going strong.

Average daily sunspot number over the November 5 – 11 reporting week was 31.3, up from 21.3 over the previous 7 days. Average daily solar flux increased from 81.6 to 90. The higher HF bands are opening up.

Geomagnetic indicators were very quiet, with average daily planetary A index dropping from 6.3 to 4.4, and middle latitude A index (based on readings from a single magnetometer on Wallops Island, Virginia) from 4.9 to 2.7.

Predicted solar flux for the following 7 days was revised downward on Thursday, November 12: Predicted flux is 85 on November 13 – 15; 82 on November 16; 80 on November 17 – 19; 78 on November 20 – 25; 80 and 82 on November 26 – 27; 86 on November 28 – December 5; 90, 88, 86, and 84 on December 6 – 9; 82 on December 10 – 11; 80 on December 12; 78 on December 13 – 22; 80 and 82 on December 23 – 24, and 86 on December 25 – 27.

Predicted planetary A index is 8 on November 13 – 15; 5 on November 16 – 19; 15, 12, and 15 on November 20 – 22; 8, 10, and 12 on November 23 – 25; 5 on November 26 – December 2; 8 on December 3 – 4; 5 on December 5 – 8; 8 and 10 on December 9 – 10; 5 on December 11 – 13; 10, 5, and 10 on December 14 – 16; 15, 12, and 15 on December 17 – 19; 8, 10, and 12 on December 20 – 22, and 5, 5, 8, 5, and 5 on December 23 – 27.

EarthSky recently published the article, “The Sun is Becoming Active Again.”

Here’s the geomagnetic activity forecast for November 13 – December 9 from F.K. Janda, OK1HH. Geomagnetic field will be:

• quiet on November 13 – 14, December 1, 6 – 8
• quiet to unsettled on November 15 – 19, 23 – 30, December 2, 4
• quiet to active on December 3, 5, 9
• unsettled to active November (20 – 22)
• active to disturbed none
• Solar wind will intensify on: November (18 – 20,) 21 – 25, (30,) December (2,) 3 – 5, (9)

Parentheses mean lower probability of activity enhancement.

We heard from Mike Schaffer, KA3JAW, of Easton, Pennsylvania:

Friday, November 6, was a good day for 10 meters between 2000 and 2100 UTC. A wide regional swath between the north Pacific Ocean, North America, and Western Europe were all hearing these call sign prefixes: CE/XR: Chile; CX: Uruguay; LU/LW: Argentina, and PY: Brazil. Modes heard were CW, FT8, and SSB.

Signal strength went from background noise level of 2 up to 9+ dB.

F2 distances ranged approximately from 3,000 to 6,000 miles (4,828 to 9,656 kilometers).

DXmaps on 28 MHz indicated the MUF reached 66 MHz above grid square FN11 (Williamsport, Pennsylvania) at 2009 UTC, then ramped up to 72 MHz above FN00 (Altoona, Pennsylvania) at 2046 UTC. Prior to local sunset at 2152 UTC, the F2 slowly faded out into the South Pacific off the mid-western coast of South America.

On November 11, around 2130 – 2320 UTC both sporadic-E (Es) and F2 started on the 11-meter band. Background noise level ranged between 3 and 4 dB. Puerto Rico stations via Es were strong, up to 20+ dB with light fading.

These southern states were heard with signal strengths ranging from 8 to 18 dB: AL, AR, FL, GA, KY, LA, MS, TN.

At 2248 UTC on 10 meters, there was light FT8 activity into Alabama and Tennessee until 2320 UTC when the DX finally went below the 4 dB noise level.

Here are some useful images from the Solar Dynamics Observatory:

Atlas Obscura on Hisako Koyama.

Sunspot numbers for November 5 – 11 were 28, 35, 37, 40, 27, 27, and 25, with a mean of 31.3. The 10.7-centimeter flux was 90.7, 93.8, 90.6, 90, 90, 86.8, and 88.1, with a mean of 90. Estimated planetary A indices were 4, 8, 7, 5, 1, 2, and 4, with a mean of 4.4. Middle latitude A index was 3, 7, 4, 3, 0, 0, and 2, with a mean of 2.7.

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.

Share your reports and observations.

SOURCE: ARRL