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ARRL Propagation Bulletin ARLP022 (2009)

ARLP022 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 22  ARLP022
From Tad Cook, K7RA
Seattle, WA  May 29, 2009
To all radio amateurs 

ARLP022 Propagation de K7RA

That was a nice string of days showing a sunspot -- May 13-19 -- a
whole week. Then it was gone, but a few days later on May 23,
another Solar Cycle 24 sunspot emerged, this time in our Sun's
southern hemisphere. But it was another of those phantom spots. This
one actually emerged, and gave us a sunspot number of 13. For that
one day it covered 30 10E-6 hemispheres. (10E-6 or 10 to the minus
sixth power is another way of expressing the fraction
one-millionth). The next day it was gone.

The area of that spot represented .003 percent of the hemisphere of
the Sun that we could see, that which was pointed toward us. Because
10E-6 is one-millionth, then 30 times that would be
thirty-millionths (three hundred-thousandths), or .003 percent.

During the seven days with a sunspot, May 13-19, the sunspot numbers
were 12, 18, 12, 15, 13, 14 and 11. On those same dates, the sunspot
area expressed in millionths of a solar hemisphere was 10, 20, 10,
20, 10, 30 and 10.

See those daily numbers at,

When we see more activity, these values can be much larger.  Note
that the sunspot area doesn't track exactly relative to sunspot
number.  The largest sunspot area was on May 18 and the largest
sunspot number was May 14.

Thanks to Carl Luetzelschwab, K9LA, for the refresher on scientific
notation and the function of E.

Conditions have been quiet, with many days showing zeros for
planetary K index.  The U.S. Air Force and NOAA predict a planetary
A index of 5 until June 3-5 when it goes to 12, then 8 for the
following two days.  Solar flux is predicted at 68 until June 5,
when it goes to 70, then 71 June 6, and 72 for June 7-14.  Perhaps
we will see sunspots return during this period.

Geophysical Institute Prague has a slightly different view for
geomagnetic activity, predicting quiet conditions for May 29 to June
1, quiet to unsettled June 2-3, and active on June 4.

Conditions should be stable for the CQ World Wide WPX CW Contest
this weekend.  You could be a sought-after multiplier with the right
prefix in that contest.  Back when I was KT7H I was one of those.
K7RA, however, is not.

Days grow longer, and Summer Solstice, the longest day of the year
is June 21.  The Vernal Equinox was March 19, and it is interesting
to compare propagation projections on those dates.

With minimal sunspot activity, from the center of the contiguous 48
states (near the center of Northern Kansas, about a dozen miles
south of the Nebraska border between Cora and Lebanon) we can
compare propagation predictions for the equinox and solstice.  To
Japan, in the Spring we might see a 20 meter opening in the late
afternoon and evening from 2100-0400z.  In Summer, that Japan
opening would run much later, beginning around 0500z with signal
strength increasing dramatically, and fading out around 1700z.

The 80 meter opening over the same path would be much shorter
duration in the Summer, because it needs darkness, and the night is
so short on the longest day of the year, more so in northern
latitudes.  We might see 80 meters open 1030-1130z, but in the
spring it runs from 0800-1430z.

From Los Angeles to Hawaii on those dates, on 20 meters it might be
easier to describe when it is least likely to be open.  Openings are
least likely on March 21 from 0500-1600z, all night.  On June 21 the
least likely period for a 20 meter opening would be 0600-1530z.

Thanks to Peter Laws, N5UWY of Norman, Oklahoma who points out that
the NY Times article referenced in last week's Propagation Forecast
Bulletin ARLP021 at was not from the
nineteenth century, but was published May 17, 1921.

Emory Stephens wrote on May 22 that, "A recent article issued by
NOAA stated there are signs that the number of sunspots should
increase.  You indicated in your posting that is an unknown area. Is
NOAA's statement science or are they making a calculated guess?"

I believe it is a guess calculated on average past cycles, and the
fact that this minimum has continued so long.  So the longer it goes
on, the more likely it is to increase soon, by their reasoning.

On May 22, George Thorward, N6CAS of Happy Camp, California wrote
about 20 meter activity over the previous week.  George said he
hears low power mobile stations working Europe while signals from
the Pacific are coming in loud and clear at the same time.  He notes
that "Europe has been wide open this week" and 10 meters has been
open from time to time also.  Check out photos of the N6CAS
installation at,

Dave Bennett, VE7YJ of Aldergrove, British Columbia wrote, "I noted
the item about KH6XS working in to EU on 15M and just thought I'd
add that he's been heard here late evenings on that band recently,
'testing propagation.' Unfortunately, I'm not set up for CW
operation, so couldn't respond to his CQ, but did note it on the DX
Cluster. That band has also been open to SA, with LU stations well
heard, though my pipsqueak signal doesn't seem to go the other way,

John Ragle, W1ZI of Hadley, Massachusetts was another who wrote
right after last week's bulletin was released.  He writes, "When are
bands 'dead' and when are bands 'unoccupied?' Here in Western
Massachusetts I keep an eye on 15 meters by switching my PSK rig to
the band and looking for traces on the waterfall around 21.070.
Today, for example (22 May, 2009), around local noon, there was
strong north-south activity, in the case of PS7YL and a few others,
resulting in 599 signals. These signals persisted for several hours
thru the afternoon. The waterfall also showed many weak traces, too
weak for copy, but there none-the-less. Since the PSK is pretty
automated, I call CQ with 15 watts and a dipole from time to time
from local noon and into the afternoon, as curiosity warrants (and
usually without results). I think that the MUF is quite high enough
for good contacts via trans-equatorial paths, but that people are
simply convinced that the band is 'dead,' and are not paying
attention. Perhaps it wouldn't hurt for people who can use
weak-signal (i.e. CW and other digital) modes to exercise them once
in a while on apparently 'dead' bands."  Thanks, John!

Red Haines, WO0W (between the two Ws are the letter O followed by
the number zero) has been watching data from ionosondes (instruments
that beam radio signals straight up to see the range of frequencies
that bounce back).  Quite a few ionosondes listed at have been silent of
late.  The data of interest is in the f0F2 column, the MUF figure.
Red writes, "A most interesting observation in the past week is the
wild excursions of f0F2 over short periods, less than an hour.  I
suspect this indicates what McNamara calls 'ionospheric storms,'
which create rapidly changing HF propagation, often seen as
'fading.' I refer to:"

"'Radio Amateurs Guide to the Ionosphere,' Leo F. McNamara.  Krieger
Publishing Company, Malabar, FL, 1994."

"This book bridges the gap between texts and technically inadequate
publications.  I recommend it highly to amateur operators who wish
to know more about propagation."

Thanks for the tip, Red!

Pete Malvasi, W2PM of Ramsey, New Jersey wrote in regard to mention
in recent bulletins of large aurora events disrupting the telegraph
circuits of yesteryear: "I've read accounts of serious disruption to
early telegraph land-lines in several period texts including an
extensive chapter in The History, Theory and Practice of the
Electric Telegraph by George B Prescott.  Reports of office fires
and fireball display are all associated with electrical storms
however and not the Aurora."

Pete sent a reference to an account of geomagnetic disruption to
telegraph cables, which you can find at

Pete continued, "Other accounts I've read in early texts describe
operating conditions in the mid 19th century to be very similar to
working present day CW with fading, static, temporary outages, etc.
They used a single wire in those days, with a ground return, and
many of the earliest lines did not use good materials for insulators
so there was a lot of leakage to ground.  Perhaps the single wire
circuits also made the lines more susceptible to the Aurora?"

Jon Jones, N0JK is currently using an indoor dipole on 6 meters in
Lawrence, Kansas.  He writes, "A multi-hop Es opening on 6M to Japan
occurred on May 22 from the central USA. I copied JE1BMJ on an
indoor dipole. W7CNK EM15 Oklahoma and stations in Colorado and
Texas worked a number of stations in Japan via multi-hop Es."  Jon
sent a list of 16 QSOs copied, mostly between U.S. and foreign
stations from 2313-2331z.

And finally, this one was sent by Danny, K7SS concerning an
intriguing tale of a possible resurgence of interest in Morse Code,
by text-message happy youth in Japan.  However, this one gives a
moderate to slightly high reading on my baloney-detector, which may
be over-sensitized.  Read it at and judge for yourself.  Note
that users can only send text messages -- not receive -- and must
check their email for replies, in addition to learning Morse Code.
Can anyone translate that Kanji text?  Or is it Katakana?

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 web page at,  For a detailed
explanation of the numbers used in this bulletin, see  An archive of past
propagation bulletins is at,

Monthly propagation charts between four USA regions and twelve
overseas locations are at

Instructions for starting or ending email distribution of this
bulletin are at

Sunspot numbers for May 21 through 27 were 0, 0, 13, 0, 0, 0, and 0
with a mean of 1.9.  10.7 cm flux was 71.8, 72.1, 70.4, 69.2, 68.9,
68.1, and 66.7 with a mean of 69.6.  Estimated planetary A indices
were 5, 5, 4, 4, 3, 4 and 3 with a mean of 4.  Estimated
mid-latitude A indices were 2, 4, 3, 4, 1, 2 and 2 with a mean of


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