ARRL

ARRL Propagation Bulletin ARLP023 (2011)

SB PROP @ ARL $ARLP023
ARLP023 Propagation de K7RA

ZCZC AP23
QST de W1AW  
Propagation Forecast Bulletin 23  ARLP023
From Tad Cook, K7RA
Seattle, WA  June 10, 2011
To all radio amateurs 

SB PROP ARL ARLP023
ARLP023 Propagation de K7RA

Although higher early in the reporting week, average daily sunspot
numbers declined over four points to 85.7 and the average of daily
solar flux numbers was down a point and a half to 101.6, when
compared to the previous week, May 26 to June 1.

Predicted solar flux for the near term is 88 on June 10-13, then 86,
84, 84, 88, 95, on June 14-18, then 92 on June 19-21, 95 and 100 on
June 22-23 and 110 on June 24-26.  Solar flux then rises to a peak
of 115 on June 28.  Predicted planetary A index is 25, 12, 8 and 8
on June 10-13, then 5 on June 14-22, then peaking at 15 on June
24-25.

Geophysical Institute Prague predicts unsettled to active conditions
June 10, unsettled June 11, quiet to unsettled June 12-13, unsettled
June 14, quiet to unsettled June 15, and quiet conditions June 16.

On June 3 there were 8 sunspot groups facing Earth, numbered
consecutively 1225-1232. Then on June 5, groups 1225, 1229, 1230 and
1231 disappeared, and new group 1233 emerged. On June 7 1233
disappeared, and on June 9 1226 left us and new group 1234 appeared.

Scott Bidstrup, TI3/W7RI sent a link to some fantastic HD videos of
solar eruptions.  Go to
http://www.thesuntoday.org/current-observations/a-spectacular-event-a-filamentprominence-eruption-to-blow-your-socks-off/ .

If you check page 14 on the report
http://www.swpc.noaa.gov/weekly/pdf/prf1861.pdf and compare it with
page 15 on http://www.swpc.noaa.gov/weekly/pdf/prf1866.pdf you can
see that some reported and predicted smoothed sunspot numbers have
changed over the last month.  The smoothed sunspot numbers for
December 2010 through November 2011 have each gone down one or two
points.  The numbers are smoothed over a year, so the current month
would average actual data that has already been measured for about
the past six months with about six months of data predicted into the
future.

Bob Cashdollar, NR8U of Newark, Ohio reports, "On June 4 at 0208z
checked 10M for activity for the 10-X Open Season Contest. When I
fired up the rig and computer, I landed right on ZL3TE working
another ZL on PSK31 on 28.120 MHz. He was very strong and I watched
the QSO on the waterfall. When he finished with the ZL QSO I called
him and to my surprise he came right back and we exchanged info.  I
thought this contest was going to be really easy. Boy, was I
mistaken! I had a lot of trouble seeing and working anybody
stateside. Checked the band this morning (June 4) around 1400z and
most stations were not workable, with a lot of scattering of the
other stations transmissions. Maybe I should go up to Bob W3HKK that
you mentioned in your last column; he just lives about 25 miles NW
of me. Maybe he has better propagation!"

Jon Jones, N0JK of Kansas reports, "I worked Dave, VP5/W5CW on 6M
SSB on June 1 at 0018z. Dave worked many across the mid USA on
double hop Es the afternoon of May 31. I was operating portable
using a 2 el Yagi."

Charlie Calhoun, K5TTT of Owasso, Oklahoma (EM26ch) wrote, "I had
something unexpected happen during the Es openings this week on 6m.
On two consecutive days I worked two different stations in totally
different directions, less than 24 hours from exactly one year
prior.  On 6/1/2010, I worked XE2NS, DL95 at 0247z, then on 6/1/2011
I worked Alfonso again at 0323z.  I thought that was pretty neat
until the next day when I worked K0PP, DN36 at 0322z and noticed him
in my log from 0305z, 6/3/2010."

Last week's Propagation Forecast Bulletin, ARLP022 (see
http://www.arrl.org/w1aw-bulletins-archive/ARLP022/2011) contained a
message from Rudy Hanau, K2EVY of Rye Brook, New York about some 20
meter backscatter propagation he experienced. The report didn't
mention this, but the propagation was observed around 0300z on May
29. I passed this on to Carl Luetzelschwab, K9LA, who had the
following comments for Rudy:

"I looked at the Boulder ionosonde data (kind of along your path to
K6ZA) for a couple days before and after May 29. The data show a
depletion (roughly 33%) of F2 region electrons on May 28 and May 29,
undoubtedly due to the spike in the A index beginning on May 27 and
continuing through May 30. I'm sure this would show up in other mid
latitude ionosondes. This is likely the reason the 'normal' path
wasn't there.

"Next I looked at Pt Arguello (Vandenberg AFB, Southern California)
ionograms from 0215-0300 UTC on May 29. They show good sporadic-E
traces that could easily support 14 MHz. The Pt Arguello ionosonde
is about 230 miles SSE of K6ZA, so it is as good an indicator as
anything that Es was occurring in the vicinity of K6ZA.

"Thus this cursory look says your unusual path might have been due
to an Es cloud. Kind of makes sense since we're in the Es season.
And it might explain K6ZA's follow-on QSO with the Nevada guy.

"I think this is about as far as I can take it without wildly waving
my arms."

Rudy responded, "I was not aware that sporadic-E effects were
noticeable all the way down to 20 meters."  Carl responded, "I agree
that the 'normal' refraction mechanism is likely out of the picture
on 20m as the high sporadic-E electron density is probably not thick
enough vertically for refraction on 14 MHz.

"I wasn't thinking refraction - I should have been more explicit. I
considered reflection and scatter from the sporadic-E cloud.

"As for conductivity, the highest electron density seen in the Pt
Arguello ionograms (8 MHz) translates to a conductivity of around
.00025 S/m on 14 MHz. Poor ground has a conductivity of .002 S/m, so
we're an order of magnitude less than poor ground. Regardless, some
reflection could occur on 20m."

Thanks, Carl!

And last, Bob Paglee, who is probably either WA7CFP or KB2ITO (he
didn't say) of Moorestown, New Jersey, sent a note after reading our
item in Propagation Forecast Bulletin ARLP021 about the geophysical
announcements on WWV ending, and thought WWV was being shut down,
which it is not.  Bob can rest easy.  WWV is not going away.  The
solar flux and geomagnetic indices that are updated every three
hours and currently are broadcast via voice at 18 minutes after each
hour are ending.  The same reports will still be available on the
internet at:

http://www.swpc.noaa.gov/ftpdir/latest/wwv.txt

That is the text of the message that is currently read on WWV.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at
http://arrl.org/propagation-of-rf-signals. For an explanation of the
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past
propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. Find more good
information and tutorials on propagation at
http://mysite.ncnetwork.net/k9la/index.html.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.

Sunspot numbers for June 2 through 8 were 118, 122, 116, 74, 67, 58
and 45, with a mean of 85.7. 10.7 cm flux was 111.6, 107.1, 102.8,
102.9, 100.2, 96.4 and 90.2, with a mean of 101.6. Estimated
planetary A indices were 8, 4, 15, 27, 7, 9, and 14, with a mean of
12. Estimated mid-latitude A indices were 6, 3, 11, 20, 5, 8, and 9,
with a mean of 8.9.
NNNN
/EX