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ARRL Propagation Bulletin ARLP009 (2020)

ARLP009 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 9  ARLP009
From Tad Cook, K7RA
Seattle, WA  February 28, 2020
To all radio amateurs 

ARLP009 Propagation de K7RA

Still no sunspots through all of February, except for the first day
of the month. I keep watching for possible sunspot activity over the
solar horizon on . Recently I noticed
a promising looking white area, and in the past few days at they pointed out two new regions just over the

As of Thursday night, both areas still appear to be transitioning
over the horizon at -90 degrees shown on the STEREO monitor at the
above URL. But so far nothing in the daily 45 day forecast of solar
flux shows any associated increase related to this.

Average daily solar flux changed slightly from 70.9 to 70.5 over the
recent week, and geomagnetic indicators remained quiet.

Predicted solar flux over the next 45 days is 70 on February 28
through March 3, and 71 on March 4 through April 12.

Predicted planetary A index is 5 on February 28 through March 3,
then 12, 12 and 8 on March 4-6, 5 on March 7-14, then 10, 8, 10, 8,
5, 10 and 8 on March 15-21, then 5, 8, 12 and 10 on March 22-25, 5
on March 26-30, then 20, 15 and 8 on March 31 through April 2, then
5 on April 3-12.

Geomagnetic activity forecast for the period February 28 to March
25, 2020 from F.K. Janda, OK1HH.

"Geomagnetic field will be 
quiet on: March 11-14
quiet to unsettled on: March 1-3, 15, 18, 21, 23-25
quiet to active on: February (28-29), March 7-10, 19-20, 22
unsettled to active on: March 4-6, 16-17
active to disturbed: NONE!

"Solar wind will intensify on: February (28 -29), March 5-7,

"Parenthesis means lower probability of activity enhancement."

Interesting article about the Kodaikanal observatory in India with
some nice butterfly diagrams and charts of daily sunspot area:

Next weekend the Apache Point Observatory in Sunspot, New Mexico
hosts an open house:

Solar activity and whale navigation:

And the New York Times weighs in:

Mike Schaffer, KA3JAW in Easton, PA monitors 11 meters for evidence
of sporadic-E skip. On Monday, February 24 he reports:

"Sporadic-E lasted for nearly three hours - 9:58 am (1458 UTC) to
12:49 pm (1749 UTC).

"At first, stations were coming from the west with the states: IL,

"Chicago, IL at 650 air miles being the furthest.

"Half-way into the activity, around 11:33 am (1633 UTC) sporadic-E
changed directions toward the south with the states: MS, FL, GA, TN,

"Jackson, MS at 1013 air miles being the furthest."

If you would like to make a comment or have a tip for our readers,
email the author at,

 For more information concerning radio propagation, see and the ARRL Technical Information
Service web page at, For an
explanation of numbers used in this bulletin, see

An archive of past propagation bulletins is at More good
information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve
overseas locations are at

Instructions for starting or ending email distribution of ARRL
bulletins are at

Sunspot numbers for February 20 through 26, 2020 were 0, 0, 0, 0, 0,
0, and 0, with a mean of 0. 10.7 cm flux was 70.8, 71.2, 70.2, 70.1,
70.2, 70.6, and 70.1, with a mean of 70.5. Estimated planetary A
indices were 8, 14, 9, 5, 4, 3, and 4, with a mean of 6.7. Middle
latitude A index was 5, 10, 7, 4, 3, 3, and 3, with a mean of 5.


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