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ARRL Propagation Bulletin ARLP017 (2007)

ARLP017 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 17  ARLP017
From Tad Cook, K7RA
Seattle, WA  April 20, 2007
To all radio amateurs 

ARLP017 Propagation de K7RA

This week we are on the road in Boise, Idaho.

This was another week with little or no sunspots. Most days had 0
spots, but from time to time a new sunspot will appear, but only
briefly. If you go to the table of sunspot readings at, you can see the brief
interruptions in the string of no-sunspot days. Go to and in the upper right corner you can
dial back to see Sun pictures and reports from any day. For
instance, there was a brief sunspot appearance on April 14, and if
you go back to the April 15 issue of, it notes the
brief appearance.

Expect more of the same conditions, with little or no sunspots.
Eventually this year we should reach a point when the only place for
solar activity to go is up.

Today, April 20, we may see unsettled geomagnetic activity.
Geophysical Institute Prague expects unsettled to active geomagnetic
conditions for April 20, unsettled for April 21-22, quiet to
unsettled on April 23, and quiet April 24-26. The U.S. Air Force
predicts April 28 as the next date for active geomagnetic
conditions, with a predicted planetary A index of 25.

Paolo Battezzato, N1XOI, who lives in Westford, Massachusetts,
northwest of Boston, sends in an interesting report from April 1 of
a PSK contact, and he says this is no April Fools joke. Paolo
writes, "I was working PSK31 around 22:45 local time when I saw a
very weak signal on my Digipan waterfall display. I clicked on the
trace and read Pablo, AY7X. I'm intrigued by the call sign, so I try
to reply to his CQ and after few attempts I contact him. Imagine my
surprise when he tells me he is with a DXpedition in Tierra del
Fuego, in FD55sd. Not bad from my FN42go grid, almost 11,000 km. By
the way, did I mention I have a resonant 20m attic dipole and I was
transmitting with just 3 Watts?"

Great story, Paolo, and I understand many PSK operators are using
simple gear with low power and even indoor antennas. In my
experiments with PSK I've been amazed at the signals it digs out of
the noise.

Barry Roseman, W0LHK of Stilwell, Kansas mentioned that during the
recent N8S expedition to Swains Island, he worked them with 80 watts
SSB on several bands, including 12 and 15 meters using a 60 meter
inverted vee pressed into service.

Ken Kopp, KK0HF of Topeka, Kansas sent a link to an article from
Physicsweb that proposes a much more modest prediction for solar
Cycle 24 than the big one predicted last year by Dikpati, et al.
This article predicts a cycle 35% weaker than the current one. Read
it at, and as Ken
wrote, "Let's hope these guys are wrong!"

Jeff Lackey, K8CQ of St. Simons Island, Georgia is living with CC&R
restrictions limiting his antennas, but he may have happened upon
just the right magic rain gutter configuration. Two weeks ago Jeff
wrote, "I use a gutter antenna and 100 watts. The gutter has five
downspouts, spaced over approximately 90 feet distance as the gutter
zigzags around the back of the house. I feed the center downspout
against a ground plane of 16 ground radials. Since January 1, 2007,
I've worked 33 zones in 121 countries. The gutter loads up fairly
well even on 160m where I've worked 34 states. I've worked Chagos on
80m, about 10,000 miles. Yesterday I worked Swains Island on 12m and
17m. And a couple of weeks ago I caught Kermadec. So the DX is
there. You just have to be patient."

That is quite an inspiration at the bottom of the solar cycle.

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 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,

Sunspot numbers for April 12 through 18 were 0, 0, 11, 0, 0, 12 and
11 with a mean of 4.9. 10.7 cm flux was 68.3, 68.3 68.2, 69.3, 69.3,
69.2, and 68.8, with a mean of 68.8. Estimated planetary A indices
were 8, 2, 4, 4, 1, 8 and 9 with a mean of 5.1. Estimated
mid-latitude A indices were 7, 1, 3, 2, 0, 6 and 6, with a mean of


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