[160m] inverted "L" antenna.

[Tom Rauch]

> how many operators out there have tried the 1/4 wave or 3/8 wave or
> extended "L" antenna. what is this antenna like on TX and rx. I have
> been told that this type of antenna is a good compromise antenna
> because of the dual polarity.( VERTICAL AND HORIZONTAL ).

Hi Willy,

There is really no such thing as "dual polarity" (polarization), and 
you would not want it anyway. 

When a horizontal and vertical component are mixed, the result is a 
tilted wave. Eznec and other simple modelling programs only can show 
plane waves of V or H, so the mixture of a wave that is tilted 90 
degrees would show as equal V and H fields. This probably confuses 
people into thinking the antenna independently has both 
polarizations.

The only way to have both H and V is with circular polarization, and 
we wouldn't want that.  

It is VERY undesirable to have circular polarization or even multiple 
angles being transmitted on any band with ionospheric propagation. 
Multiple angles or lobes simply add to the multipath QSB, they do not 
reduce it. Minimum fading occurs with a sharp pattern aimed at the 
right angle, not a broad one!  

As a matter of fact in broadcasting they often call a vertical just 
over 1/2 wl long a "non-fading vertical". 5/8th wl antennas, because 
of the high angle lobe causing deep QSB when it mixed with the low 
angle signal, actually fell out of favor for lower gain but cleaner 
patterns with only one lobe!  

All of that aside, the horizontal section won't contribute anything 
anyway unless it is very long...and that would probably not be a good 
thing. Inverted L's work and are favorites because the vertical 
section radiates, and they are easy to match and feed. They are good 
antennas if you have a good ground system, but only because they are 
reasonably good verticals.

 
73, Tom W8JI
W8JI@contesting.com