[TowerTalk] LPDA optimal height

[jimlux]

On 2/14/17 9:15 AM, Jim Thomson wrote:
> Date: Tue, 14 Feb 2017 07:23:58 -0500
> From: "john at kk9a.com" <john at kk9a.com>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] LPDA optimal height
>
> As you figured out, there is no perfect height. I would avoid going too
> high where you create nulls at critical angles. My question is why do you
> want to use a Log Periodic? I have never modeled one but they look to be
> nothing more than multiple dipoles and they can have common mode current
> if the coax is not properly routed around the hot boom. I used a small LP
> once from the Caribbean and never felt loud.
>

I wonder about wire LPDAs (such as the one from TCI used in SW 
broadcast).. they can be installed sloping, so that the elements for a 
particular frequency range are at the same height (in wavelengths) above 
the ground.

Of course, rotating such a LPDA requires towers on wheels or some such..