On Tue, 31 Jan 2006 16:14:38 -0600, "hasan schiers"
wrote:

Necessity being the mother of invention, bit me. Last weekend was CQWW CW on
160m. I stumbled on it and had no 160m antenna. I have a terrific performer
for 80m, an inverted L with 33, 60' radials stapled on the ground. I also
have a Carolina Windom 80 at 42' fed with perhaps 100' of RG8x.

Since it was a cw contest, I figured, brute force stuff with my tuner. Very
interesting results.

I tried the 80m inverted L, feeding just the center conductor, and also
tying the shield and center conductor together ...both cases feeding it as
an end fed wire.

Hi Hasan,

You tied the shield and center conductor together - isn't that a short
circuit for the inverted L?

I got no band noise and very poor signals, but what the

Sounds like a short.

heck, I worked 10 or 15 stations who were running S7 or better in spite of
things.

Could they have been much better?

I could tell I wasn't being heard very well. (I was also running
about 500w output).

Still sounds like a short.

Then I tried the same trick with the CW-80. I fed the center conductor
only...band noise jumped up to S-3, signals were amazingly loud, and I
started working everyone I could hear...first call.

Sounds like a cleared short.

I'm at a loss to explain why it would seem to work so well as a DX antenna
for 160m. Pleased, but surprised. Any theories?

One theory is you could have done a whole lot better - but that is
pure speculation. Another theory is you could have done a whole lot
worse - that doesn't need to be proven because we can all achieve
that.

Am I somehow shunt/gamma feeding my tower?

Could be. Could be so lossy as to defy SWR too.

I also had no tuner arcing, no rf in the shack, no RFI in the hi-fi,
....zippo...all the RF appears to go where I would like it to, but I have NO
idea why. I prefer to understand things and not just rejoice in my dumb
luck. Ideas?

For one, I've seen a number of posts recently proclaim the
accomplishments of DX, Low Angle antennas. The two are not
necessarily tied at the hip. It is all predicated on the bank shot
against the ionosphere, and a low angle could as easily end up in the
drink as it could in Lower Slobovia. And Versa Vice, a high angle
(call it 30 degrees) could as easily hit Ulan Bator as it could drill
into Pike's Peak.

True, a high angle is more susceptible to multi-hop losses, unless it
is bouncing over the Pacific on the first two caroms. Without a valid
propagation model tied to the radiation distribution characteristics,
calling an antenna a low Angle, DX performer is a mighty flight of the
imagination.

Short answer: a propagation modeler tracking real time results will
answer more questions than attaching claims to simple monopoles or
dipoles.

I've used WinCAP with a highly distorted antenna response curves to
probe launch angles. WinCAP comes with sample antennas, like the
common quarter wave vertical. I've edited that file such that output
at all elevation angles, except one, are severely reduced. Basically
a one degree height elevation lobe set at one particular angle (for
the sake of argument, a 5 degree launch angle, ±½ degree). When it
reaches Europe, the footprint floods France.

Now, we know that such an antenna is nigh on impossible to build for
HF, and the common vertical is going to launch very useful power over
a far greater span of angles. The upshot of this is that instead of
that ±½ degree, we take the typical ±15 degrees around a typical
launch angle of 20 degrees, and you cover a lot of ground at the other
end * IFF * the Ionosphere will support them. And just as much power
will probably hit France even though we've quadrupled that "low"
launch angle FROM 5 degree launch angle, ±½ degree TO 20 degree launch
angle ±15 degrees.

73's
Richard Clark, KB7QHC