ARRL

ARRL Propagation Bulletin ARLP026 (2009)

SB PROP @ ARL $ARLP026
ARLP026 Propagation de K7RA

ZCZC AP26
QST de W1AW  
Propagation Forecast Bulletin 26  ARLP026
From Tad Cook, K7RA
Seattle, WA  June 26, 2009
To all radio amateurs 

SB PROP ARL ARLP026
ARLP026 Propagation de K7RA

Thanks to Carl Luetzelschwab, K9LA for writing last week's
Propagation Forecast bulletin.

Two new sunspots appeared last week, numbered 1022 and 1023, and
both were Cycle 24 spots.  1022 lasted through June 23 and 1023
until June 24.  On June 24 geomagnetic indices were unsettled.

This weekend is ARRL Field Day, and conditions should be stable.
Planetary A index is predicted to be around five, which is quiet.

Chip Margelli, K7JA wrote about some surprising openings last week.
He writes, "Sunspots or no, there are DX opportunities even with a
solar flux of 67. Both Friday and Saturday nights (U.S. time June
19-20), the 21 MHz and 28 MHz bands were open to Japan from my
location in southern California, and along much of the West Coast,
around 0500-0800 UTC (that's 10 PM to at least 1 AM!).  Both nights,
the 15-meter CW band was crawling with loud JA signals from stations
working the All Asian DX Contest, and there were many loud signals
on 10 meters, as well. I fear many did not think to check ten at
this hour, but it very much was open."

He continues, "And Saturday night I worked 54 JA stations in a nice
run on 50 MHz, so perhaps those noctilucent clouds were being kind
to me."

Steve Brandt, N7VS of Portland, Oregon had a similar observation.
On 10 meters CW last Friday night (at 0336z Saturday) Steve worked
JK1YMM in the All Asia CW Contest with S7 reports in both
directions.  Steve also observed sporadic-E openings this week out
to about 1,000 miles, and said other stations have reported working
Japan on 10 meters this week.

In last week's bulletin, Carl mentioned the upcoming DXpedition to
Glorioso in July.  Now he has written a set of predictions for
propagation to Glorioso from various areas, and you can see it at
http://mysite.verizon.net/k9la/id11.html.  Just click on the
"Glorioso in July 2009" link.

I received some interesting mail from Red Haines, WO0W of La
Crescent, Minnesota.  I did a search for past emails from him, and
came across an unread mail from December, 2007.  Just to review and
clarify, an ionosonde is a tool for measuring the critical frequency
(f0F2) for the area just above.  It sweeps an RF signal, beaming
straight up, and looks for reflections.

Some quotes from Red occupy the next few paragraphs.

"Though we use the sunspot number and the solar flux index to assess
propagation expectations, there is only an indirect connection
between these indices and propagation.  Neither sunspots nor the
radiation measured by the solar flux index directly increase or
decrease the levels of ionization in the ionosphere.  All three are
determined, somewhat independently, by physical processes on or in
the Sun.

"Sunspots and the solar flux are caused by solar conditions that are
often associated to a limited degree with high energy radiation that
reaches Earth and ionizes molecules in the atmosphere.  Only the
energetic radiation (UV, X-ray, and Gamma rays) from the Sun or
other sources ionize those molecules.  The solar flux radiation is
not energetic enough. The sunspots are only a visual phenomena
associated with solar events, including radiation.  It often happens
that no solar radiation associated with a sunspot reaches Earth.

"In past years, we didn't have any better predictors of propagation
than the sunspot number and the solar flux index.  They remain
useful, but we must recognize their limitations.  In fact,
propagation correlates very poorly with them.  Smoothed sunspot
numbers are useful to study the solar activity cycle.  Smoothed
sunspot number doesn't predict the next day's propagation or even
the next cycle's timing or magnitude.  In fact, the smoothed SSN
cannot be calculated until 6 moths have passed.  The daily SSN is
just about meaningless to propagation.

"Today, we have better indicators of propagation potential. Hams may
view near real time measures of X-ray radiation from the GOES
satellites.  See http://www.swpc.noaa.gov/today.html.

"The various propagation beacons are very useful to assess current
propagation.

"A source of near real time ionospheric conditions, including the
various critical frequencies, may be accessed at
http://www.swpc.noaa.gov/ftpdir/lists/iono_day/. This index links to
the worldwide system of ionosondes to report measured values on
short time intervals, typically near 15 minutes.  The shortcoming is
the relatively small number of ionosondes, which requires
interpolation to estimate the MUF for a propagation path, as well as
educated guesses regarding details of the path.

"The Australian IPS Radio and Space Services offer several maps that
attempt to depict interpolated propagation conditions, based on
ionosonde measurements.  For an example and links to additional
products, see http://www.ips.gov.au/HF_Systems/4/3."

In a message from June 15, Red wrote:

"Perhaps you already noted the large increase in f0F2 reported by
the ionosonde at Boulder.  Rapid fluctuations beginning after 1200Z
June 14 reached high values as high as 14 MHz.  The fluctuations
were prominent.

"By the time I noticed and turned to the DX beacons, values were
back to usual and the RTTY signals interfered too much to discern
much on 14.1 MHz.  By that time, about 2300z, I didn't hear any
beacons on 21.150 MHz.  I sure wish the RTTY operators were more
aware of the value of those beacons, to themselves as much as to
others.

"Signals on 80 meters at 2330z, from net stations that I work every
day at that time, were about 20 dB lower than has been typical
during recent weeks.  These were stations within MN.  Perhaps
D-layer absorption was increased.

"On a region net at 0045z, also 80 meters, signals were a bit lower,
but were back to normal at 0230z, as were the MN net signals at
0250z.

"I haven't found the cause of the ionospheric fluctuations.  I
examined the graph of X-ray flux and it was 'flatlined.'  I found no
evidence of any major particulate density reaching Earth from the
Sun.  Of more general interest, the Millstone station resumed
posting ionosonde readings for a couple weeks, though not
continuous, but has discontinued the postings.

"I suspect that the IPS maps are relatively inaccurate for lack of
ionosonde data.  I not considerable disparity between those maps in
the US and the Boulder data.  I began recording the Boulder data to
study that in greater detail."

And finally on June 23, this from Red:

"You probably noted the appearance in the southern hemisphere of two
sunspot groups with a SSN of 24 on June 22.  Did you also notice a
burst of low energy X-ray on June 22 and the large excursions of
f0F2 at about 1400z, 2300z (June 22z), and 0800z (June 23z)?  The
f0F2 reported by Boulder reached 11 MHz at 0800z June 23 and
displays a series of high and low excursions.

"The other ionosondes in the USA continue to report no data.  IPS
maps are not tracking these excursions, probably because data needed
for the map model is lacking."

We also had several reports on grayline propagation recently.  Here
are two of them.

On June 12, Roland Spoon, AH6RR of Kailua Kona, on the Big Island of
Hawaii wrote, "The past 2 weeks has just been hopping on 20 meters
here in Hawaii I have been making contacts almost world wide with
the exception of South America (???) Evening Grayline is open to
Africa, Asia, Middle East, Europe and Oceania. With openings to
Europe until 10+ pm local time, signals are between S5 and 20 over
9. Morning grayline Favors the Middle East and Africa with some
light but workable Europe. Stu KH7DX reports that between midnight
local and 4am good openings to the Indian Ocean  Africa. We have
been having a blast working the pile-ups."

Another grayline report came from Brian Webb, KD6NRP of Ventura
County, California.  On Monday at 0350z (Sunday night local time)
Brian was on PSK31, and writes, "I called CQ on 14070 kHz with no
takers.  Just as I was reaching up to close my software, someone
answered.  The other station had a funny call and I suspected my
system hadn't decoded the signal correctly.

"But the other station repeated his call and I was receiving it
correctly. I then proceeded to have a brief, but exciting QSO with
Nigel, E51SC, in Rarotonga in the South Cook Islands.

"Despite the low solar flux and my compromise antenna, the contact
apparently was made possible due to grayline propagation. A check of
my propagation software confirmed that at 0400Z the terminator
(day/night line) ran through southern California to the South Cook
Islands."

To end, note that the solar flux numbers at the bottom are not
resolved to one tenth of a point.  For some reason I could not
connect to the FTP server at Penticton that hosts the data.

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://www.arrl.org/tis/info/propagation.html.  For a detailed
explanation of the numbers used in this bulletin, see
http://www.arrl.org/tis/info/k9la-prop.html.  An archive of past
propagation bulletins is at, http://www.arrl.org/w1aw/prop/.

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

Instructions for starting or ending email distribution of this
bulletin are at http://www.arrl.org/w1aw.html#email.

Sunspot numbers for June 18 through 24 were 0, 0, 0, 12, 24, 12, and
14 with a mean of 8.9.  10.7 cm flux was 68, 67, 67, 67, 68, 68, and
67 with a mean of 67.4.  Estimated planetary A indices were 4, 4, 6,
7, 3, 4 and 19 with a mean of 6.7.  Estimated mid-latitude A indices
were 2, 1, 5, 6, 2, 5 and 16 with a mean of 5.3.
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/EX