sexta-feira, 28 de abril de 2017

ARLP017 Propagation de K7RA

ARLP017 Propagation de K7RA

Each of the average solar and geomagnetic indices rose last week
(April 20-26) over the previous seven days.
Average daily sunspot number rose from 8.6 to 35.7, and solar flux
rose from 76.5 to 81.4.
Average daily planetary A index went from 8 to 26.4, and average
daily mid-latitude A index from 6.3 to 18.4.
The day with the most geomagnetic activity was April 22 when the
planetary A index was 54. One the same date, Alaska's College A
index (near Fairbanks) was 86.
Predicted planetary A index is 8, 5 and 5 on April 28-30, then 14,
10, 8 and 10 on May 1-4, 15 on May 5-6, 8 on May 7-8, 5 on May 9-14,
8 and 15 on May 15-16, and then into a more active period at 30, 25,
45, 50 and 30 on May 17-21. Then 20 on May 22-24, then 15, 8, 5 and
20 on May 25-28, 10 on May 29-31, 15 on June 1-2, 8 on June 3-4, and
5 on June 5-9.
Predicted solar flux values are 79 on April 28-29, 78 on April 30
and May 1, 77 on May 2-4, 75 on May 5-14, 80 on May 15-18, 85 on May
19-24, 80 on May 25-28 and 75 on May 29 to June 10.
OK1HH sent us this geomagnetic activity forecast for the period
April 28 to May 24, 2017.
"Geomagnetic field will be:
Quiet on May 9-10, 12-13
Mostly quiet on April 30, May 7
Quiet to unsettled April 29, May 2, 4, 14, 21-24
Quiet to active on April 28, May 1, 3, 8, 11, 15-16, 19
Active to disturbed on May (5-6,) 17-18, 20
"Amplifications of the solar wind from coronal holes are expected on
April 28, May (1-5,) 6-8, (9-11,) 18-22
"Remark: - Parenthesis means lower probability of activity
enhancement and/or lower reliability of prediction."
I thought I ran this last week, but apparently not:
https://www.youtube.com/watch?v=JR7D9zTygao
These always seem to come out after the bulletin is posted.
You might want to check this for more up-to-date videos from Dr.
Tamitha Skov:
https://www.youtube.com/user/SpWxfx/videos
Thanks to Don, N5DM for that tip.
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 the ARRL
Technical Information Service web page 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 20 through 26, 2017 were 26, 39, 29, 43,
41, 36, and 36, with a mean of 35.7. 10.7 cm flux was 80.7, 82.2,
83.6, 82.5, 80.2, 81.3, and 79.6, with a mean of 81.4. Estimated
planetary A indices were 30, 19, 54, 41, 20, 12, and 9, with a mean
of 26.4. Estimated mid-latitude A indices were 20, 11, 37, 24, 19,
10, and 8, with a mean of 18.4.
https://www.youtube.com/watch?v=JR7D9zTygao&authuser=0
____________________________________________________ 
ARRL Web site <memberlist@www.arrl.org
QST de W1AW
Propagation Forecast Bulletin 17  ARLP017
From Tad Cook, K7RA
Seattle, WA  April 28, 2017
To all radio amateurs


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