Here is a reference to a technical look at short loop antennas from the
1950's by Wheeler.

H. A. Wheeler, "Fundamental Limitations of Small Antennas", Proc. IRE, vol.
35, pp. 1479-1484

This is can found in a technical library with access to the IEEE
publications web site (e.g. university or military tech library)


Thane-fer
Homer


"Dave Platt" wrote in message
...
d. If a receiving signal is well polarized in
one direction, say vertically, how much loss
would one expect if the receiving antenna is
oriented such that its preferred polarization is
horiz. ?

The usual figure one sees bandied about is 20 dB.

I've seen it quoted as "up to 30 dB". That's probably under ideal
(or ideally-bad) conditions, though.

e.g., for a rubber-duckie scanner antenna ?

There's an additional penalty of 20 dB imposed on
any antenna that has the word "duckie" in its name.
;-) ;-) ;-)

Heh. Yeah. Last weekend, my partner-in-repeater-crime and I ran some
simple outdoor-range tests on a few 2-meter beams, using an HP signal
generator and HP spectrum analyzer. We used a quarter-wave whip,
mag-mounted on a sheet of steel, as the reference antenna.

A two-element HB9CV beam was around 8 dB better than the reference
antenna, with a front-to-back ratio of 6-8 dB.

An Elk log-periodic 6-element beam measured out as quite similar to
the HB9CV (but has a lower SWR across the band) - 8 dB up, and about 7
dB front-to-back.

A 3-element Yagi made out of PVC and steel measuring tape segments,
designed for foxhunting, was 9-10 dB up and had about a 20 dB
front-to-back ratio at its deepest null.

Rubber duckies? Ugh. A Yaesu helically-wound duck was around 10 dB
worse than the reference antenna. An RD-9 "high gain" base-loaded
2-meter/440 superflexible antenna was around 12 dB worse than the
reference antenna.

I'd always heard that rubber duckies were actually rubber dummy loads.
Now I've actually seen the results for myself. Yeech.

--
Dave Platt AE6EO
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