> Yuri K3BU Said:<BR>>
> If installed over salty marsh. Ever tried to model or compare
> any vertical
> over average and "perfect" sea ground and see the gain at LOW angles?
>
> Thomas KN4LF Says:
>
> Speaking of low angles, when it comes to 160 meter vertical
> antenna's you
> can get a bit of a lower take off angle (TOA) from a full 1/4
> wave vertical
> or electrical 1/4 wave tee vertical of 10-20 degrees, versus ~30
> deg. with
> the inverted L. However it's an exercise in futility as the
> nighttime E
> layer MUF blocks 160 meter low angle transmitted radio signals
> from ever
> reaching the F layer to be propagated. So unlike with HF
> propagation, MF
> propagation success does not require the lowest of take off
> angles to work
> DX.
>
> Also higher take off angles of ~30 degrees via the inverted L
> are better
> able to take advantage of the low signal loss E valley-F layer
> propagation
> duct mechanism, a form of Chordal hop propagation.
>
> - -... ...- -,
> Thomas F. Giella, KN4LF
That may be true according to theories you use. :-)
But according to "my" theory http://www.k3bu.us/propagation.htm
sometimes low angles and ducting/refraction do not jive with conventional
wisdom, especially on 160.
It is not just angles but efficiency of radiator with elevated current
distribution and effective radial field - ground conditions. It does not harm
to have the antenna lobe come down to horizon and provide extra gain at low
angles (and ground wave). Propagation on 160 is not exactly text book case and
from my experience, especially at low sunspot years, low angles become more
prevalent (atmosphere/ionosphere height decreases). Proof of that is also long
beverages that outperform their "standard" cousins. It means working some 25
JAs in a contest, when others were happy with one or two.
At the times I can see some significant differences between long Beverages and
higher angle Circle Vertical 8 Array.
73 Yuri, www.K3BU.us
www.TeslaRadio.org go to PHOTOS and W8LRL
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