[BC] Shively Vertical Antenna question

[Richard Fry]

RH of WPIO Radio wrote:

>Can anyone offer a reason why the Shively 6510 Vertical only
>polarity antennas are not straight up and down like a normal
> vertical dipole antennas.
>And....wouldn't that off-axis from vertical cause some
>inadvertent horizontal polarity to be radiated?
______________

Was hoping that Bob Surrette would answer, but using NEC-2 to look at a 
similar "bent dipole" and comparing it to a straight one shows about equal 
peak gain in the elevation patterns for the two.   But the bent dipole no 
longer has a null at the zenith and nadir, so it would not be decoupled as 
well from other antennas lying in the same vertical plane, and for a given 
max ERP its RFR on the ground directly under it would be higher.

The bent dipole model also generated a very small h-pol field, but it was 
so low as to be insignificant.  I didn't bother documenting it.

Here is a comparison of the free-space patterns of the two (dipoles only), 
where zero degrees is in the azimuth direction that the bent dipole is 
pointing.

  http://i62.photobucket.com/albums/h85/rfry-100/DipoleCompare.jpg

RF