[Elecraft] Windom Antennas

[Ron D'Eau Claire]

-----Original Message-----
I know the theory and cannot disagree with it.  But in the mid 50s I was =

able to work much DX with 75 W CW (DC in) and a 135 ft Windom up no more =

than 15 ft.  73, Phil


I've done something similar at times over the years.=20

It shows that anecdotal evidence is LOUSY at "predicting" antenna
performance. There are two reasons for this behavior, from what I've =
read.

One reason for the DX is that there is STILL some radiation at very low
angles... it is merely much, much weaker. Anyone who has ever gone QRPp
knows just how far a few mW can go!  What we'll never know is how much
stronger our signals might have been with a different (better?) antenna.

Another reason is a "wild card" that I see pop up in propagation =
literature
from time to time. That is, under certain conditions, higher angles of
radiation do not necessarily mean poor DX performance.

The old text books show us how "skip" works, with the inevitable picture
showing the signal "hopping" between the surface of the earth and the
ionosphere. According to some researchers, the problem with that picture =
is
that simple path loss calculations shows that the loss over two or three
skips would be so much that it would take megawatts to produce the =
signal
strengths at the other end that we routinely get. They say that the loss
each time the signal hits the earth is just too great to support that =
model.

They offer an alternative suggestion. They hypothesize that the signal =
is
becoming "captured" by the ionosphere, where it is "ducted" around the =
earth
until it hits an anomaly that "kicks" it loose to return to earth. These
anomalies are created primarily by the areas of the earth that are being
subjected to darkness and sunlight, so the effects are rather =
predictable,
repeatable and conform to our experience in the "real world".=20

Since no "ground" reflections are involved, the losses on this sort of
propagation supports the sort of signal strengths we see over DX ranges.

The angle at which a signal must intercept the ionosphere to become
"captured" for DX propagation is most often as shallow as possible. That
supports the observation that "lower angles of radiation are better for =
DX".
But it is also believed that, under certain propagation conditions near =
the
transmitting end, much higher angles of radiation can also be captured =
by
the ionosphere, producing astonishing DX results from an antenna that =
was
not supposed to be capable of such performance.=20

Ron AC7AC
K2 # 1289