[Lowfer] tilting vertical antennas

[Dale Parfitt]

james fisher wrote:

> In my experience on two meters tilting a beam can
> influence the takeoff angle of the radio waves leaving
> the antenna. If you use a j pole antenna the gain is
> generated by moving more of the radiated power to a
> lower angle as compared to the horizon, this results
> in gain and better contacts. If a vertical antenna is
> tilted the take off angle will be changed. This might
> be a good or bad thing depending on what you are
> trying to do with it and the effect of the ionisphere
> where the signal at hf is reflected back to earth.
> what impact htis would have on ground wave is another matter
>

Takeoff angle is ultimately a function of height above ground measured
in wavelegths.
Tilting a beam up or down may effect it slightly but as a secondary
effect.
J poles achieve their gain (over a quarter wave, zero dB over a half
wave) simply because it is a half wave radiator compared to a quarter
wave. The main lobe is at the horizon unless the mast and feed have not
been properly isolated- then the takeoff angle is anybody's guess.

I went back to AO and again modeled a haf wave vertical antenna, I see
gain changing as the tilt angle increases ( I went from vertical to 20
degrees) but the lobe takeoff angle remained the same. Gain was achieved
by the antenna becoming directional.

And then again I could be wrong. I never thought SSB would catch on.
Dale W4OP