Register Account

Login Help

ARRL Propagation Bulletin ARLP022 (2013)

ARLP022 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 22  ARLP022
From Tad Cook, K7RA
Seattle, WA  May 31, 2013
To all radio amateurs 

ARLP022 Propagation de K7RA

Average daily sunspot numbers sank nearly 50 points to 94.3 this
week, and the average daily solar flux was down over 16 points to
117.8.  Geomagnetic indices were quite high, due to a solar wind

The predicted solar flux for the near term is 105 on May 31 through
June 1, 110 on June 2-5, then 105, 115, 125 and 130 on June 6-9, 135
on June 10-11, 140 on June 12-13, then 135, 125, 135 and 130 on June
14-17, and 125 on June 18-20.

Predicted planetary A index is 18 on May 31, 15 and 10 on June 1-2,
8 on June 3-4, 5 on June 5-10, then 8, 12, and 8 on June 11-13, and
5 on June 14-17.

OK1HH predicts the geomagnetic field will be quiet to active on May
31, active to disturbed June 1, quiet to active June 2, mostly quiet
June 3, quiet to unsettled June 4, quiet June 5-7, mostly quiet June
8-9, quiet June 10, quiet to unsettled June 11, quiet to active June
12-14, mostly quiet June 15-17, quiet June 18, quiet to unsettled
June 19-20, active to disturbed June 21, and quiet to active June

The Australian Space Forecast Centre issued an alert at 0524 UTC on
May 30 warning of increased geomagnetic activity due to a solar wind
stream from a coronal hole. For May 31 they predict mostly unsettled
to active conditions with the chance of minor storm periods in the
latter half of the UTC day at high latitudes. For June 1 they expect
mostly unsettled conditions with a chance of active periods.

Rich Zwirko, K1HTV of Amissville, Virginia wrote on May 29: "Worked
my first European of the 2013 6M Es season at 2200Z yesterday, May
28th. Worked F8GGD and heard two other French stations on CW here at
my FM18ap Virginia QTH. They were in and out of the noise here for
about 45 minutes before the band opened to the southeast. Worked
three stations in Venezuela as well as stations in J6, PJ4 and HI
(Dominican Republic, not Hawaii!).

"Did you know that in the past 9 years on 77% of the May 29 dates
there was E-Skip between the Eastern USA and Europe, and 66% of the
days on May 30th?

"Check out this and other very interesting Es data from Kevin,


"Lots of 6M ops in the Eastern U.S. will have their beams on Europe
today. The Es season has begun."

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

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 23 through 29 were 117, 99, 107, 92, 87, 75,
and 83, with a mean of 94.3. 10.7 cm flux was 134.5, 127.3, 121.3,
120, 110.1, 104.8, and 106.9, with a mean of 117.8. Estimated
planetary A indices were 7, 20, 32, 18, 13, 8, and 2, with a mean of
14.3. Estimated mid-latitude A indices were 8, 17, 25, 19, 8, 8, and
2, with a mean of 12.4.


Instragram     Facebook     Twitter     YouTube     LinkedIn