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ARRL Propagation Bulletin ARLP022 (2015)

ARLP022 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 22  ARLP022
From Tad Cook, K7RA
Seattle, WA  May 29, 2015
To all radio amateurs 

ARLP022 Propagation de K7RA

This week the average daily sunspot number dropped 36 points to
56.1, and average daily solar flux was down 25.7 points to 97.6.
Geomagnetic numbers indicated more stability than the previous week
(May 14-20) with average daily planetary A index declining from 10
to 4.4, and mid-latitude A index down from 9.7 to 5.

The latest forecast from NOAA/USAF has solar flux at 90, 95, 100,
105 and 110 on May 29 through June 2, 115 on June 3-4, 125 and 120
on June 5-6, 115 on June 7-10, 110 and 105 on June 11-12, 100 on
June 13-14, 95 on June 15, 90 on June 16-17, 95 on June 18-20, 100
on June 21-23 and 95, 90, 105, 110 and 115 on June 24-28, and 120 on
June 29-30. Flux values then peak at only 125 on July 1-2, before
dropping back below 100 on July 12.

Planetary A index is predicted at 12 and 8 on May 29-30, then 5 on
May 31 through June 6, then 10, 25 and 20 on June 7-9, 12, 8 and 5
on June 10-12, then 8, 15 and 12 on June 13-15, 5 on June 16-23,
then 8, 12 and 8 on June 24-26 and 5 on June 27-28.

F.K. Janda, OK1HH predicts the geomagnetic field will be quiet to
unsettled May 29, mostly quiet May 30, quiet to unsettled May 31,
mostly quiet June 1, active to disturbed June 2, quiet to active
June 3, mostly quiet June 4-5, quiet to unsettled June 6, quiet to
active June 7-9, disturbed on June 10-11, mostly quite June 12,
quiet June 13, quiet to active June 14, active to disturbed June 15,
quiet to active June 16 and quiet on June 17.

Howard Lester, N7SO of Schuylerville, New York (FN33eb) wrote on May
28, "I got on the radio last evening to see if there was any E2 on 6
meters. The band was dead at 2330 UT, but I left it on 50.125 to
monitor. At 0005 UT I heard a K0 from Missouri calling CQ, coming in
loud at S5, so I jumped off the sofa and we had a nice little chat
for a couple of minutes. After, I heard him work a VA3. My antenna
is a little triangular loop up 15 feet."

Last week David Moore sent a couple of links to articles about
observations from the NASA Solar Dynamics Observatory. See them

On May 22, Bob Kupps, HS0ZIA of Chiang Mai, Thailand wrote, "Hi we
had a very nice 15m opening last night May 21 from around 1430-1530
UTC (2130-2230 local time) right over the North Pole into almost all
of North America from New Brunswick to Arizona. Using a K3 at 100 W
to a 5/5 Optibeam stack at 15 and 30 meters elevation. Fun!"

Check out Bob's antennas on his page. Quite a stack!

Don't forget the CQ World Wide WPX CW Contest this weekend. Look
here for more info:

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 the ARRL
Technical Information Service web page at For an explanation of the
numbers used in this bulletin, see An archive of past
propagation bulletins is at More good
information and tutorials on propagation are at

Archives of the NOAA/USAF daily 45 day forecast for solar flux and
planetary A index are in downloadable spreadsheet format at and .

Click on "Download this file" to download the archive and ignore the
security warning about the file format.

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 May 21 through 27 were 36, 81, 69, 74, 63, 46,
and 24, with a mean of 56.1. 10.7 cm flux was 101.8, 99.1, 97.7,
98.7, 96.5, 94.5, and 95.2, with a mean of 97.6. Estimated planetary
A indices were 3, 3, 4, 5, 4, 6, and 6, with a mean of 4.4.
Estimated mid-latitude A indices were 5, 4, 5, 6, 3, 6, and 6, with
a mean of 5.