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The K7RA Solar Update

03/13/2020

I felt cheated this week when a much-anticipated sunspot only appeared just briefly, disappearing after two days.

Sunspot region AR2758 only appeared on March 8-9, with daily sunspot numbers of 13 and 12. Average daily sunspot numbers for the week rose from zero to 3.6, while average daily solar flux increased (minimally) from 70 to 70.2.

Average daily planetary A index declined from 6.7 to 4.4, and average middle latitude A index decreased from 4.6 to 3.6.

Predicted solar flux over the next 45 days is 70 on March 13-20, 72 on March 21-22, 70 on March 23 through April 4, 72 on April 5-18, and 70 on April 19-26.

Predicted planetary A index is 5 on March 13-26, then 12 and 8 on March 27-28, 5 on March 29 through April 5, then 10 and 8 on April 6-7, 5 on April 8-13, then 8, 12 and 8 on April 14-16, 5 on April 17-22, then 12 and 8 on April 23-24 and 5 on April 25-26.

The vernal equinox occurs next week, at 0350 UTC on March 20. 2020. This is when the Southern and Northern Hemisphere are bathed in approximately equal doses of solar radiation, and like the autumnal equinox six months later, is considered a good time of year for long distance HF communications.

I see some new activity over the solar horizon, an active, bright spot, but this time in the Northern Hemisphere: https://stereo.gsfc.nasa.gov/

Geomagnetic activity forecast for the period March 13 to April 8, 2020 from OK1HH.

Geomagnetic field will be
quiet on: March 13-14, 23-25, 29-30
quiet to unsettled on: March 15, 18 (- 21), 26, 28, April 2-7
quiet to active on: (March 22, 31, April 1, 8)
unsettled to active on: (March 16-17, 27)
active to disturbed: None.

Solar wind will intensify on: March (17-22,) 28, (29-31)

Remarks:
- Parenthesis means lower probability of activity enhancement.
- The predictability of changes remains lower at present.

Ken, N4SO, reports monitoring NCDXF 15-meter beacons using a half-square antenna. "I heard CS3B on 21.150 MHz. The transmitter is located in Madeira (northwest coast of Africa). Reception was on March 4, 2020 at 1931 and 1934 UTC.

“The beacons in the NCDXF International Beacon Project broadcast on four different power levels: 100 W, 10 W, 1 W, and 100 mW, giving a very good indication of propagation quality.

“I heard the very strong CS3B beacon on at least 3 power levels. The last one is uncertain.

“It's not unusual to hear NCDXF beacons on 3 power levels, if the signal is strong and the frequency is quiet. Other NCDXF beacons heard daily on 21.150 MHZ are OA4B and YV5B with variable signals, or not at all, but often heard approximately at 1900, 2000, or 2100 UTC."

Steve Gardner, KB1RUV noted strong 15-meter activity into the Caribbean last Saturday.

A local newspaper article in Duluth about recent sunspot activity: https://bit.ly/339S1Xk

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 March 5 through 11, 2020 were 0, 0, 0, 13, 12, 0, and 0, with a mean of 3.6. 10.7 cm flux was 69.5, 70, 69.9, 70.2, 70.8, 70.8, and 70.5, with a mean of 70.2. Estimated planetary A indices were 4, 5, 5, 5, 5, 4, and 3, with a mean of 4.4. Middle latitude A index was 3, 4, 5, 3, 5, 3, and 2, with a mean of 3.6.

 



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