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The K7RA Solar Update

04/10/2020

After five days of new Cycle 25 sunspot activity, sunspots vanished. Average daily sunspot number rose from 3.6 last week to 5.1 this time. The average daily sunspot number over the days they were visible, March 31 through April 4, was 12.2, but these observations straddled two reporting weeks.

Average daily solar flux rose from 69.4 to 70.2. Geomagnetic indicators remain quiet, with average planetary A index declining from 7.7 to 6.6, and average mid-latitude A index slipping from 5.9 to 5.3.

Predicted solar flux for the next 45 days is 70 on April 10-13, 68 on April 14-23, 70 on April 24 through May 7, 68 on May 8-20, and 70 on May 21-24.

Predicted planetary A index is 8 on April 10-11, 5 on April 12-14, 10 on April 15, 8 on April 16-19, 5 on April 20-25, 10 on April 26-27, 5 on April 28 through May 6, 8 on May 7-8, 5 on May 9-11, 10 on May 12, 8 on May 13-16, 5 on May 17-22 and 10 on May 23.

F.K. Janda, OK1HH, wrote:

"Geomagnetic activity forecast for the period April 9-May 5, 2020

Geomagnetic field will be
quiet on: April 10, 20-21, May 2-3
quiet to unsettled on: April 11-13, 17-18, 22-24, 28-29
quiet to active on: (April 9, 14, 16, 25, May 1)
unsettled to active on: (April 15, 19, 26-27, 30, May 4-5)
active to disturbed:- nothing predicted
Solar wind will intensify on: April 9, 12-13, (15-16,) 17-19, (20,) 26-28, May 4-6

Remarks:
- Parenthesis means lower probability of activity enhancement.
- The predictability of changes remains lower as there are no indications."


In her latest video, Dr Tamitha Skov, WX6SWW, is excited about signs of Cycle 25: https://youtu.be/UKsPSnSZers

Frank Donovan, W3LPL sent this out to the Potomac Valley Radio Club yesterday, and shared it with us for this bulletin: "Some of us have noticed a slight uptick in solar activity since Christmas Day when two Cycle 25 spots -- AR 2753 and AR 2754 -- appeared.

Only one of the five subsequent sunspots -- AR 2757 --  has been from old Cycle 24.  All of the sunspots over the last 12 months have been relatively weak and have had little effect on propagation.
“Although the beginning of Cycle 25 won't be officially declared until late this year, its highly likely that it began on Christmas Day 2019. The next important event to look for is a strong Cycle 25 sunspot, hopefully that will occur this year."
Two relevant links:
https://iopscience.iop.org/article/10.3847/2515-5172/ab79a1

https://www.syfy.com/syfywire/welcome-cycle-25-a-new-solar-magnetic-cycle-has-begun

Jon Jones, N0JK, wrote yesterday: "With the early start to the summer sporadic-E season, some Es are linking from North  America to South America.

“On April 9, LU9FF and LU9FVS spotted K4CVL on 50.313 MHz FT8 at 2230z. K4TR and NN4X in South Florida spotted stations in Chile. Signals were strong enough for SSB with AC4TO EM70 working CA3SOC and LU8YD on 50.110 MHz SSB at 2224z.

“KN4NN, AA5AU and N0FW (EM79) Ohio were also making FT8 contacts with South America on 6 meters."
 
KA3JAW monitors 11 meters, (that's right, Citizens Band) for interesting propagation events from Easton, PA (FN20jq): "Sporadic-E was up on eleven meters on Tuesday, April 7 from 6:45 until 11:00 pm local (ET).

“During this event, the Es funnel path coned me stations only from the coastal Gulf of Mexico states of Louisiana, Mississippi, Alabama.

“I find it somewhat strange that Es remains active up till late nightly hours during the opening of Spring season.

“I thought Tuesday, March 31 was a good DX day monitoring the 11-meter band with reception of Tyler, Texas at 1,254 miles.

“But today, Saturday, April 4 was way more exciting with reception of multiple Puerto Rican stations rolling-in from 6:42 pm local (ET) until 8:00 pm that were 374+ miles further in range.

“One operator there was making greater than 1,600 miles contacts from West Virginia up into Rhode Island.

“At around local sunset at 7:29 pm the baseline background noise level environment  jumped 30 dB when one particular operator running high power would key the microphone.

“Puerto Rican operators would occasionally peak 20 dB over local operators.

“The distance from my home to San Juan, Puerto Rico runs 1,628 miles. This would be at the far end range of a single-hop sporadic-e path. Perhaps the ion cloud was tilted a few degrees from horizon."

 

Your author has been using the FT8 mode with WSJT-X software to observe marginal propagation modes, in which communication occurs due to refraction via whispery ionized clouds. Using low power and a deliberately marginal antenna (short piece of wire, thrown out the basement window, never more than 4 feet above ground) I can immediately see signal reports from many stations via https://www.pskreporter.info/pskmap.html. Some of the results on 160 through 10 meters seem quite remarkable, considering the antenna and power level.

If you would like to make a comment or have a tip for our readers email the author at 
k7ra@arrl.net.

For more information concerning radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere.

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/.

Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins.

Sunspot numbers for April 2 through 8, 2020 were 12, 13, 11, 0, 0, 0, and 0, with a mean of 5.1. 10.7 cm flux was 69.8, 69.9, 70.1, 71.2, 69.9, 69.9, and 70.4, with a mean of 70.2. Estimated planetary A indices were 7, 9, 5, 5, 3, 4, and 13, with a mean of 6.6. Middle latitude A index was 7, 7, 4, 4, 2, 3, and 10, with a mean of 5.3.

 



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