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ARRL Propagation Bulletin ARLP024 (2016)

ARLP024 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 24  ARLP024
From Tad Cook, K7RA
Seattle, WA  June 10, 2016
To all radio amateurs 

ARLP024 Propagation de K7RA

I thought it was too early in the decline of this solar cycle to
start seeing days with no sunspots (when the sunspot number is zero)
but I was wrong.
There were no sunspots on June 3 to 6.  2015 had zero spotless days,
2014 had just one, and there were no spotless days in 2012 and 2013.
There were just two spotless days in 2011, so we have already seen
twice the number of spotless days that 2011 had.  2010 had 51
spotless days, and 2009 had 260 spotless days.
The last time there were four or more spotless days was December 18
to 24, 2010 when there were no sunspots for an entire week.
The average daily sunspot number dropped to 7.7 this week, from 33
the week before.  Average daily solar flux went from 87.4 to 80.7.
Geomagnetic indicators were up slightly, with planetary A index
going from 8.9 to 11.6 and mid-latitude A index from 9 to 9.4.
As of Thursday, June 9, sunspots and solar flux both seemed to be
Daily sunspot number on June 7 to 9 was 12, 15 and 22, and daily
solar flux was 78.5, 80.1 and 85.2.
Predicted solar flux for the near term is 85, 90 and 95 on June 10
to 12, 90 on June 13 and 14, 95 on June 15 and 16, 90 on June 17 to
20, 85 on June 21 to 24, 80 on June 25 to 28, 78 on June 29 through
July 4, 82 on July 5 to 7, 85 on July 8 to 11, 90 on July 12 to 17
and 85 on July 18 to 21.
Predicted planetary A index is 8, 14, and 18 on June 10 to 12, then
12, 8 and 6 on June 13 to 15, 10 on June 16 to 18, 5 on June 19 to
22, then 10, 12 and 8 on June 23 to 25, 10 on June 26 and 27, 5 on
June 28 through July 1, then 25, 20 and 8 on July 2 to 4, 5 on July
5 to 8, 12 on July 9 and 10, then 8 on July 11 and 12, then 5, 15
and 10 on July 13 to 15, and 5 on July 16 to 19.
Petr Kolman, OK1MGW of the Czech Propagation Interest Group sends
his geomagnetic forecast:
Geomagnetic field will be: 
Quiet on June 19 and 20, July 1 
Mostly quiet on June 15 and 16, 21 and 22, 29 and 30, July 5 and 6 
Quiet to unsettled on June 10, 14, 25, 28, July 4 
Quiet to active on June 11 to 13, 17 and 18, 23 and 24, 26 and 27 
Active to disturbed on June (18), July 2 and 3
Increases of the solar wind from coronal holes are expected on June
11 to 13, 17 and 18, 23 and 24, 26 and 27, July 2 and 3.
- Parenthesis means lower probability of activity enhancement.
Average daily solar flux over this past week was 80.7, but back in
December 2010 that week of no sunspot numbers had an average daily
solar flux of 79.3, very close.
Sunspot numbers are somewhat subjective, based on a visual count of
sunspot groups, the number of sunspots in those groups, and the
total area covered by sunspots.
Solar flux is an actual measure of one type of radiation reaching us
from the sun, radio energy with a wavelength of 10.7 cm, or 2.8 GHz.
This is supposed to give us a clue about how much our ionosphere is
being charged, although x-rays have greater significance.  Also
remember that because the distance from earth to the sun varies
slightly throughout the year, this affects the solar flux number
because it is weaker when we are farther away.
We are only two weeks away from Field Day weekend, so what
conditions might we see on June 25 and 26?  The predicted solar flux
for June 24 to 26 is 85, 80 and 80, while the predicted planetary A
index is 12, 8 and 10, which is not bad.
We are including Friday in the data report, even though Field Day
only runs from 1800 UTC Saturday, June 25 until 2059 UTC Sunday,
June 26 because Friday conditions should affect conditions on
We received this from N8II on June 9, which he titled "Late WPX
"Recently the solar flux has dropped substantially to 80 as of today
and I heard no signals on 15 meters an hour before sunset here.  It
was over 100 as I recall during the WPX CW contest May 28 and 29 and
the band really came to life for the contest.
15 meters sounded so good Friday night, I decided to try single
band.  I never have heard so many New Zealand prefixes as I worked
Friday evening, ZL1, 4, ZM1, 2, 3, 4 and there were multiple ZL1's
and 4's active.  To boot I worked 5W1 (western Samoa), WH6, NH7, KH6
x 3, VK2, 3, 4, 6 (though on 15 meters), VK7, JA2, 3, JH4 (Japan,
all weak).
The biggest surprise was a loud EA3 in Spain with my Yagi west (off
CA stations were noticeably weak most of the evening as were some
7's.  I closed out the evening with an A31 at 0230Z with 135 QSO's
in the log.  At 1747Z I found almost no EU (did get A60, United Arab
Emirates) and not many USA stations either, so I bagged it in after
8 minutes.  A check of the band at 2025Z revealed not only southern
EU, but loud northern EU, UR, and UA6 area stations.  About the only
areas missing were North Russia, France, Netherlands, and British
I logged several Lithuanians, Swedes, and Finns (Aland Is. very
loud).  The activity died off by 2120Z, but I was still working a
mixture of EU and Caribbean/SA up until 2154Z when I worked a loud
Sicilian and QRT'ed for dinner.
Conditions from 2330Z were similar to the day before with a weak JA
opening from 0151 to 0211Z when I QRT'ed.  Of note was a S7 Finn at
2340Z or 0234 local in Finland!  Again CA was weak most of the
evening, but there were some nice prefixes to the south like XR0Y
(Easter Is.) and T49.
Sunday AM I missed a good opportunity, because the band opened well
much earlier to EU than it ever has for weeks!  Signals were loud
from all of EU at my 1253Z start and even a RU9 was loud.  UP0
(Kazakhstan) was S9+ at 1416 and I found XW1 Laos, very rare from
the east USA!
Conditions seemed the best at 1300Z, but I was running stations
fairly well off and on thru 1515Z.  This included two western
Siberia area QRP stations.
Signals from the Baltic states and Finland were louder than stations
farther south at times.  Again 15 closed early to EU about the time
the sun was setting on the EU side or even earlier.  By 1800Z, most
of EU had died out and the few stations north of the Med area worked
were weak and fluttery.
However there was good activity to the south and several stations in
the Carib/SA area were running with low numbers sent.  I spent over
an hour picking off new prefixes mainly to the south.
At 2100Z a few stations from Black Sea Russia and many Ukraine
stations were back in along with Turkey, DL, YT, SP, HA, CT, F, 9A50
and I which was not as widespread as Saturday.  From 2133 to 2156
three weak JA Japanese were worked.
After a nice steak I grilled, it was back on at 2300Z to finally
find decent strength JA's, but activity was low.  USA 6, 7, 9, 0's
were all quite loud.  In the last 25 minutes E/SE Asia beyond JA
started coming thru working BY5 in South China and very weak two
QSO's with Eastern Malaysia and one Western Malaysia.  It was a
thrill to hear loud EU and work Asian DX again on 15 after a
dreadful month of May with April not much better.  The only areas
not worked were southern AF (no activity?), Indonesia, and NE Asia
west of JA.  This was a huge improvement from what I expected.
There was a good opening on 15 to Indonesia on June 4 from around
1230Z to 1400Z or later.  I logged 4 or 5 stations there all with
good signals except one about S4 with the rarest being a YC6.  This
was the first time I have heard them on 15 since mid-April.
Sporadic E has been rather poor so far, very few 10 meter openings
that I have been able to catch."
David Moore sent this article about coronal holes:
For more information concerning radio propagation, see the ARRL
Technical Information Service 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 June 2 through 8 were 27, 0, 0, 0, 0, 12, and
15, with a mean of 7.7.  10.7 cm flux was 85.2, 83.2, 80, 79.1,
78.5, 78.5, and 80.1, with a mean of 80.7.  Estimated planetary A
indices were 4, 3, 4, 29, 26, 9, and 6, with a mean of 11.6.
Estimated mid-latitude A indices were 5, 5, 5, 23, 21, 10, and 6
with a mean of 9.4.