In a message dated 7/23/2002 4:02:45 AM Pacific Daylight Time,
n4zr@contesting.com writes:
>
> At 12:43 PM 7/23/02 +0200, Maurizio Panicara wrote:
> >Independently by its peculiar high angle radiation, not every contact
> needs
> >low angle radiation, an orizontal antenna close to a real ground has large
> >losses that seriosly affect the overall efficiency.
> >Any modeling software I tried seems to under estimate those real losses.
>
> Which raises again the question of using stacked dipoles for an NVIS
> antenna, with the upper one fed and the lower one used as a
> reflector. Hypothetically, wouldn't that improve the loss situation, if
> the reflector was some distance above the ground surface?
>
> 73, Pete N4ZR
> Check out the World HF
> Contest Station Database at
> www.pvrc.org
>
Reflectors underneath do improve performance of high angle antennas. I've
used them under horizontal quads and installed quad reflectors on the ground
of progressively difference sizes with obvious beneficial results. I will
have a QTH where I can install one installation with and one without a
reflector or ground radials of the right orienation and compare--side by
side.
One comparative test is is worth 1000 opinions and soft ware
predictions. (Old K7GCO Axoim)
--- StripMime Report -- processed MIME parts ---
multipart/alternative
text/plain (text body -- kept)
text/html
---
|