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ARRL Propagation Bulletin ARLP023 (2015)

ARLP023 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 23  ARLP023
From Tad Cook, K7RA
Seattle, WA  June 5, 2015
To all radio amateurs 

ARLP023 Propagation de K7RA

For seven days from May 28 through June 3, average daily sunspot
numbers dropped from 56.1 the previous week to 34.3.  Average daily
solar flux barely changed from 97.6 to 97.8 over the same two weeks.
But both numbers show a rising trend in recent days.
Predicted solar flux is 125 on June 5, 130 on June 6, 135 on June 7
to 11, then 130, 120 and 110 on June 12 to 14, 100 on June 15 and
16, 95 on June 17 to 22, 90 on June 23 to 25, 95 on June 26 to 28,
100 on June 29, then peaking at 120 on July 7 and 8 and dropping
back below 100 after July 13.
Predicted planetary A index is 5, 8 and 12 on June 5 to 7 then 15,
25 and 15 on June 8 to 10, then 10, 5 and 8 on June 11 to 13, then
15 and 12 on June 14 and 15, and 5 on June 16 through July 3, then
10, 25, 20 and 12 on July 4 to 7.
OK1HH predicts the geomagnetic field will be quiet to unsettled June
5, quiet to active June 6 to 9, disturbed on June 10, quiet to
unsettled June 11, mostly quiet June 12, quiet on June 13, active to
disturbed June 14, quiet to active June 15 and 16, quiet on June 17
to 21, quiet to unsettled on June 22 to 25, quiet to active June 26,
active to disturbed June 27, quiet June 28 to 30, and mostly quiet
on July 1.
OK1HH predicts increasing solar wind on June 12, June 16 and 17 and
June 27 and 28, with reduced prediction reliability during the
latter two periods.
On May 28 the daily sunspot number was 11, the lowest non-zero
sunspot number possible.  This means there was just one sunspot
group visible.  There are no sunspot numbers between 1 and 10,
because there is a value of 10 for each sunspot group, and a value
of 1 is added for every sunspot in the group.
The last time the daily sunspot number was 11 was July 16, 2014 and
the following day the sunspot number was zero.  Note that this was
just a few months after the peak of cycle 24, which I reckon to be
around February and March 2014 using our three month moving average.
Prior to that we look back to January 14 and 15, 2011 to find the
sunspot number at 11 on both days, on the rising side of cycle 24.
Look here for a long range forecast of smoothed sunspot numbers: .  These are International Sunspot numbers,
on a different scale from the ones we present in this bulletin.
Note it shows the current cycle peaking in March and April 2014,
just like our 3-month moving averages of daily sunspot numbers.
Four years in the future we see the next cycle minimum in summer
We keep track of a 3-month moving average of sunspot numbers to spot
trends and figure our cycle peaks and minima.  At the end of May we
now know the most recent 3-month average.
The average centered on December 2014 through April 2015 is 107.8,
98.2, 78.1, 68.2 and 72.4, so we saw a small uptick in the latest
numbers.  Now to make us all feel better, I will cherry pick data.
The monthly sunspot averages for March, April and May 2015 were
61.7, 72.6 and 83.  No foolin'.
Check out "Best NASA Footage of Giant Sunspots" here:
.  Be sure to click each image to get a better look, and take the
video sequence up to full HD resolution by clicking the gear in the
lower right corner and selecting Quality: 1080 or 720.
Steve Sacco, NN4X of Saint Cloud, Florida passed along an
interesting article about plasma tubes.  Don't miss the comments:
Jeff Hartley, N8II of Shepherdstown, West Virginia sent this report:
It has been a fun week on the radio with exceptional polar openings
on 15 meters, the WPX CW contest and a 6 meter opening on double hop
to VE5, UT, CO, AZ, and CA on Tuesday evening followed by a good
Caribbean opening to Cuba, KP4, FG, and HI3 Wednesday morning.
Considering the solar flux has hovered just below or above 100, the
polar path openings morning and evening have been amazing on 15
meters in the past week.  Having the North Pole illuminated 24 hours
a day makes for some great polar openings.  The solar flux level
seems to matter much less for good openings during the summer months
than the rest of the year.  And the K index has been kindly low.
During the WPX contest May 30 and 31, conditions on 15 meters may have
been a bit below normal Saturday, but there was still plenty of DX
to be worked and Sunday was considerably better except for a lack of
strong JA signals from 0000Z-0200Z.  Around 0200Z, my JA vs. Chinese
QSOs were running neck and neck, very surprising.  The band was open
well to SE Asia and China every morning and evening.  I worked about
20 total Chinese QSOs including several never heard before with
prefixes such as BH4, BG3, BG6, BG8, and BG9 as well as working YE1,
YB2, YC1, XW1 (heard every morning and evening), XV9, HS4, HS0, E21,
9V1, 9V50, and JT5.  Many Far East signals were S9 or better.
In addition the South Pacific was loud all the way out to VK and ZL
the first evening.  I worked the Azores around 0200Z with no northern
EU then, but right before the band closed I made long path EU QSO's
with S50 and UR.  Saturday morning at 1200Z started with only Eastern
EU to Central Asia coming thru, with western EU finally loud around
Stations in 7Z1 (Saudi Arabia), 4L8, and two A65 in the UAE were
worked.  By 1800Z, there were still plenty of loud big gun EU
stations, but northern EU was gone along with Eastern EU north of UR
and UA6.
By 2100Z, near midnight in Eastern EU, conditions had improved with
loud signals from all over EU including Scandinavians, then signals
began fading fast around 2200Z.
Sunday was even better in our morning into the whole northern
hemisphere including loud SE Asians and JA's and even the very
poorly equipped EU stations were good copy from 1200 to 1500Z.  EU was
fading out by 2100Z, but I finished the last 15 minutes running
Conditions into Asia seemed even better in the late morning of June
2, working very loud prefixes YC8, YB0, 7K4 (Japan), JH1, and BD7.
Late morning on June 3 was also good with strong signals from EU
Russia and RX0SA on 15 CW.
Last week during the Seattle International Film Festival I attended
a screening of "The Russian Woodpecker", a documentary about the
Soviet cold war era Duga 3 OTH HF RADAR that plagued HF radio users
all over the world during the 1970s and 1980s.  Like many of the
festival films, the film maker attended the first showing and
answered audience questions afterward.
The film was factual, but of course part of the story were the
conspiracy theories which naturally arise in a society in which
information is tightly controlled.  The director told us he used a
small helicopter drone to capture the wonderful high resolution
close-up footage of the massive antenna system, which sits within
the Chernobyl Exclusion Zone in Ukraine.
Among the impressive hardware seen in this film, some of my
favorites were the large black rotary dial telephones left behind in
the facility.  I would love to have one, and still have a landline to
hook it to.
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
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 28 through June 3 were 11, 23, 27, 47, 38,
39, and 55, with a mean of 34.3.  10.7 cm flux was 93, 92.3, 95,
94.3, 100.4, 101, and 108.5, with a mean of 97.8.  Estimated
planetary A indices were 7, 7, 5, 5, 8, 3, and 4, with a mean of
5.6.  Estimated mid-latitude A indices were 8, 5, 5, 6, 9, 4, and 5,
with a mean of 6.


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