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ARRL Propagation Bulletin ARLP016 (2008)

ARLP016 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 16  ARLP016
From Tad Cook, K7RA
Seattle, WA  April 11, 2008
To all radio amateurs 

ARLP016 Propagation de K7RA

No sunspots for seven days, as of Thursday, April 10.  We may see
sunspots return around April 21-28.  This is based on recent
activity rotating out of view around the Sun and (we hope)
reappearing later this month.

If you look at,, which
was Thursday's forecast, you see predicted solar flux remaining at
70 until April 20, when it reaches 75, then 80 on April 21.  The
predicted higher solar flux should correlate with the return of
sunspots.  This prediction is updated daily after 2100z.  After
2100z April 11 you can see the new prediction by changing
041045DF.txt at the end of the URL to 041145DF.txt.  You can also go
to, to select a
daily forecast from the list, but frequently there is a delay before
the latest forecast is listed, and you can see it much sooner by
changing the date in the URL as shown above.

From that same forecast you can see quiet geomagnetic conditions
predicted until April 22-24.  Geophysical Institute Prague predicts
quiet to unsettled conditions April 11, quiet April 12-13, quiet to
unsettled April 14, unsettled April 15, quiet to unsettled April 16,
and back to quiet on April 17.

Rob Steenburgh, KA8JBY sent some links useful for detecting sunspots
on the Sun's far side, using helioseismography.  See, and, for images.  Note that
you can also animate these to see recent activity in motion.  The
technique is described at,

In Propagation Forecast Bulletin ARLP007 (see in mid-February, we
mentioned an article in a daily business publication which spoke of
an upcoming Maunder Minimum.  In the article were fabricated quotes
from Dr. Kenneth Tapping, who works at the observatory in British
Columbia where we get our daily solar flux data.

I was surprised to see this same article in the monthly VHF column
in CQ Magazine recently.  But I saw it on March 31, and it was the
April issue.  I understand that this was really supposed to be some
sort of April Fools' jest, but it went awry, probably due to
miscommunication with the editor, who was already running a
traditional whimsical April item.  Once edited, it lost the April 1

Of course there is a long tradition in amateur radio publishing
regarding strange and fantastic articles in the April issue.
Sometimes it is difficult to tell.  For instance, as a 12-year old
Novice I was unaware of this tradition, and was very interested to
read in an April QST about some new paint that could be applied to
towers.  It was supposed to "shift" reflected light "outside the
visible spectrum," and therefore render the structure invisible.
Well, nearly so.  It should still block light from passing through
it, but the article claimed the effect was some kind of fuzzy
non-image, a sort of visual void of uncertain nature.

I didn't realize that this was a joke until reading the Letters
section in the May issue.  Imaginative readers had a lot of fun with
this, and one woman wrote that her ham husband was trying out the
paint on a recent Saturday, and she hadn't seen him since.

Mike Schatzberg, W2AJI of Tryon, North Carolina wrote to report
conditions during the recent period when we actually had daily
sunspot activity.  He was mentioned previously in this bulletin, in
2006 in Propagation Forecast Bulletin ARLP047 (see  He wrote again
about excellent conditions on 20 meters.

On April 4 Mike wrote, "I had to let you know about the unusual and
steady strong signals I have been working on 20 meters the past 3
days.  East coast propagation to the Far East and Indonesia have
been extraordinary.  Low power stations, less than 100 watts, and
with wire antennas abound, and I am able to read them with S5 to S9
signal strengths on my Orion II transceiver."

He continues, "Two Americans, HS0ZCX, Chuck, with only 100 watts,
and a wire beam antenna, and XU7ACY (NO2R), Peter, have been booming
into the East Coast with S9 signals.  They are heard during the
morning hours at about 13:00 Zulu, along with Ralph, HS0ZSC who is
also very strong.  YB0BCU, Yan, is always S9 from Jakarta during the
same time period."

Mike goes on to say, "The evening hours have also been a delight
into the Orient.  Propagation remains good into Japan for much of
the night.  But many lower power stations can also be worked on SSB,
from both China and Taiwan.  Last night, between 01:00 and 03:00
Zulu, once you steer around the many calling Asian Siberian
stations, Japan, China, and Taiwan were extremely active.  BD2QAF,
BU2AQ, JA2AXB, all had S5 or better signals with low power."

He says, "I should add that short path is again open in the evening
hours back into the South Pacific.  Todd, ZL2SP, was mobile, with
100 watts and a mobile whip, and he was S5 here.  VK signals were Q5
during this period also."

Mike continues, "It seems that many American stations are not aware
of the late evening openings as yet, and the bands are really quiet
while working the low power DX.  If this is just the beginning, and
we are still enjoying sunspots from Cycle 23, with little action
from new Cycle 24, how much better will things get? I guess I better
get my log periodic finished for the higher bands because 15 and 10
are already having their 'DX Moments!'"

He ends by saying, "I have been using my usual 20 meter monoband
Yagi, with 44 foot boom, at 75 feet for DXing.  It doesn't get much
better than this.  Strong signals and little QRM.  Enjoy."

Mike sure has some nice antennas in a great location.  See them at, and  Note the last link shows he has been
looked up over 41,000 times on that site.  That indicates a very
active ham.  See also on his personal web site he has photos of
other stations and their antennas.  Don't miss VK3MO's photos at,

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 April 3 through 9 were 14, 0, 0, 0, 0, 0, and 0
with a mean of 2.  10.7 cm flux was 76.4, 73, 71, 69, 69.1, 69.8,
and 68 with a mean of 70.9.  Estimated planetary A indices were 2,
11, 21, 18, 12, 9 and 12 with a mean of 12.1.  Estimated
mid-latitude A indices were 2, 8, 9, 11, 9, 6 and 9, with a mean of


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