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ARRL Propagation Bulletin ARLP026 (2011)

ARLP026 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 26  ARLP026
From Tad Cook, K7RA
Seattle, WA  July 1, 2011
To all radio amateurs 

ARLP026 Propagation de K7RA

The predicted Field Day geomagnetic storm never appeared, although
conditions were unsettled leading up to last weekend.  Planetary A
index was 7 and 7 on Saturday and Sunday, and mid-latitude A index
numbers were 5 and 6.
Reports so far indicate an enjoyable and productive Field Day 2011.
Average daily sunspot numbers for the week were down 13 points
compared to the previous week, and average daily solar flux was off
by over 7 points.
Predicted solar flux for the near term is quite a bit lower than
recent numbers.  The forecast shows solar flux at 87 for July 1-5,
then 90 on July 6-8, 88 on July 9, 92 and 96 on July 10-11, and 100
on July 12-15, then back to 88 on July 16.
Expected planetary A index is 8, 10, 12 and 8 July 1-4, 5 on July
5-7, 7 on July 8-9, and 5 again on July 10-18.
Geophysical Institute Prague says watch for unsettled conditions
July 1, unsettled to active July 2, unsettled July 3, quiet to
unsettled July 4-5, and quiet July 6-7.
Good news from WM7D and W7GTF who heard on a WWV broadcast that the
Space Weather Prediction Center decided not to drop the hourly
geo-physical report, and due to all the feedback they may actually
expand it.  See the official announcement at
Now that June has passed, let's look at the 3-month moving average
of sunspot numbers.  Centered on June 2010 through May 2011 the
moving average of daily sunspot numbers were 20.4, 23.2, 28.9, 33,
35.6, 31, 30.1, 35.3, 55.7, 72.3, 74.4 and 65.9.  We have to look
quite far back to find moving averages of daily sunspot numbers as
high as the last few months.  Back in 2004, the 3-month moving
average of daily sunspot numbers centered on June through December
were 80.8, 78.1, 69.3, 66, 66.3, 61 and 52.2.
Mel Frost, KD7DCR of Whitehall, Montana (DN-35) reports that on 6
meters at 0301z on June 29 he worked NZ5E and AB5F, both in eastern
Arkansas.  AB5F faded from S-6 into the mud about 35 minutes later,
NZ5E started at S-9 +10 and faded to S-8, until they finally signed
off at 0420z.  He couldn't find any evidence on DK Sherlock of
others enjoying this path.
Jon Jones, N0JK of Wichita, Kansas (EM17jr) on June 25 wrote: "I
worked PJ6D at 1704z today.  They came up on a QSB peak, worked AC0A
then me.  Sent the usual '599' but more like a 579.  Solid clear
signal and clean confirmed QSO.  Earlier heard them at 1600z but
very weak like on scatter".
"They are running an amp, so I was hearing them better than they me.
Had to call several times to get a response.  PJ6D faded down
shortly after I worked them.  Had just come in the apartment after
helping the XYL load some furniture in our car.  Could have easily
missed PJ6D.  Could not go out portable today due to T-Storms".
Also on June 25, Bill Hohnstein, K0HA of Seward, Nebraska (EN10lx)
wrote: "I worked PJ76 at 1502z and PJ6D at 1506z.  Both were strong
then.  The PJ's and others in that area were stronger with 120
degree Yagi phasing.  That's how my antenna was set when I worked
them.  By 1520z signals from that area were better with 0 degree
Yagi phasing".
"I think that I had my earliest run of JA's today:  29 between 2137
and 2216z, with two more around 2240z.  I think that JA6LCJ in PM52
was my furthest (10,457 km)".
Bill also added:  "I did a lot of antenna checks while working the
JA's.  All that I checked were stronger with 120 degree phasing
between two of my Yagis!  Most were pretty much unworkably weak with
0 degree phasing AND with just my 6M7 being fed.  My adding the
phasing option is definitely a success!"
Bill linked to a recording he made of JN1NDY at  He also added "And, if you
want to hear how JA4DND's signal sounded, go to: .  That's how the pileup sounded
most of the time".
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 at  For an explanation of
the numbers used in this bulletin, see  An archive of
past propagation bulletins is at  Find more good
information and tutorials on propagation 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 23 through 29 were 47, 62, 47, 26, 30, 37,
and 45, with a mean of 42.  10.7 cm flux was 96.3, 96.2, 93.6, 90.1,
89.2, 86.9, and 87.3, with a mean of 91.4.  Estimated planetary A
indices were 18, 10, 7, 7, 5, 4, and 2, with a mean of 7.6.
Estimated mid-latitude A indices were 16, 10, 5, 6, 4, 2, and 2,
with a mean of 6.4.


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