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The K7RA Solar Update

05/01/2020

There were several sunspot appearances this week. Sunspot numbers on April 25-29 were 11, 14, 12, 0 and 24, giving a weekly average of 8.7. Average daily solar flux changed from 69 to 69.2.

Geomagnetic activity remains quiet, with average daily planetary A index declining from 7.3 to 5.6.

On Thursday, new sunspot activity continued, with the daily sunspot number for April 30 at 35, and the total sunspot area four times what it was on April 25-27. This new activity is both encouraging and exciting.

Predicted solar flux is 70 on May 1-5, 69 on May 6-16, 70 on May 17-31, 69 on June 1-12, and 70 on June 13-14.

Predicted planetary A index is 5 on May 1-2, then 8, 8, 10 and 8 on May 3-6, 5 on May 7-17, then 10 and 8 on May 18-19, 5 on May 20-23, 8 on May 24-27, 5 on May 28-31, 12 on June 1, 5 on June 2-13, and 10 on June 14.


Geomagnetic activity forecast for the period May 1-26, 2020 from F.K. Janda, OK1HH.

Geomagnetic field will be
Quiet on: May 2-3, 13-14, 26
Quiet to unsettled on: May 1, 6-8, 15-16, 25
Quiet to active on: (May 4, 9-10, 17, 20, 22, 24)
Unsettled to active on: May 5, (11-12, 18-19, 21, 23)
Active to disturbed: None predicted

Solar wind will intensify on: May (4,) 5-6, (11-12,) (18-21, 23,) 24

- Parenthesis means lower probability of activity enhancement.

- The predictability of changes remains lower as there are no indications.

Michael Guerin, W6MVT, of Upland, California wrote: "The evening of 27 April 2020 was an odd one for those of us in Southern California. After the end of the Florida QSO Party 20 meters became quiet here. Yet in the evening around 0300 UTC the only three signals heard were there ZL1s - ANH, BD and WN. Each courteously received each of us and we enjoyed clear (uncontested) time with our neighbors to the southwest. It was like having an exclusive pipeline. Nice change."


KB1DK from Trumbull, Connecticut wrote: “On Saturday morning April 25th between 1350-1430z, I listened to YB0AZ and YB0IBM working stations in the Midwest on 14.190 and 14.210, respectively. Both stations were armchair copy, S8 to S9 on an inverted vee OCFD antenna. Those lucky enough to work YB0IBM also got to contact his friends YB1DNF and HS0ZOA. YB0AZ said that it has been nearly a year since he worked stateside stations. Nothing was heard this morning (4/26). I did not contact either station.

“On 17 meters, ZL1WN is a regular on 18.150 to 18.160 between 2100 and 2130z. I have been hearing Ross on most afternoons with a strong S8 to S9 signal though the fading can get pretty bad.


I think it is interesting that YB0AZ says it has been nearly a year since he last worked USA stations. He should be hearing from North America more often as the sunspot cycle picks up.

Sean, K8KHZ, wrote: “Forty meters was great on April 18 at 0100z. I was able to work EA8BWW Canary Islands. I used a low-height inverted G5RV antenna with just 100 watts on SSB. I was surprised the band was open.”


Be sure to check the current issue of ARRL Letter for comments by K9LA on differences between historic sunspot numbers. The link is 
http://www.arrl.org/arrlletter?issue=2020-04-30 .

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 23 through 29, 2020 were 0, 0, 11, 14, 12, 0, and 24, with a mean of 8.7. 10.7 cm flux was 68.7, 69.7, 68.9, 69.2, 69, 69, and 69.9, with a mean of 69.2. Estimated planetary A indices were 4, 8, 5, 6, 7, 6, and 3, with a mean of 5.6. Middle latitude A index was 4, 6, 5, 5, 6, 6, and 4, with a mean of 5.1.



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