Hmm... 1/8 wave above the ground for elevated radials... now, at 160m
that would be about... 60 feet! Compared with actually trying to achieve
that miracle, I guess it would be worth the trouble to lay some serious
wire on the ground.
73, Dick WC1M
> -----Original Message-----
> From: Jim Brown [mailto:jim@audiosystemsgroup.com]
> Sent: Sunday, July 22, 2007 1:25 PM
> To: Tower Talk List
> Subject: Re: [TowerTalk] 160 M Inverted L Questions....???
>
> On Sun, 22 Jul 2007 08:41:15 -0700 (PDT), R. David Eagle wrote:
>
> >Is there a huge difference in efficiency between 40 and 60 feet?
>
> In general, the vertical portion of the antenna provides the
> vertically polarized component of radiation, and is more lower
> angle radiation. The horizontal portion radiates horizontally
> polarized, and at a higher angle.
>
> Another form of antenna closely related to the inv L is the Tee,
> which has wire on both sides of the top of the vertical. That
> antenna tends to have ONLY vertical radiation, which is better if
> you want to work DX.
>
> >I will stay away from the elevated radials debate.
>
> Science is not a matter of debate, but of facts, carefully proven.
> There's a lot of science that shows that elevated radials work
> fine -- IF they are actually elevated. In general, radials don't
> behave as elevated until they're at least 1/8 wavelength above the
> earth. The closer they are to the earth, the more they act like
> they were actually on the ground (that is, you need a lot of
> them). The more they're elevated, the more they act like elevated
> radials (that is, you don't need very many of them). By "work
> fine" I mean that they provide a low resistance (low loss) path
> for antenna return current. By not work fine, I mean that they
> couple in a lot of loss from the earth, which wastes transmitter
> power (and makes your signal weaker by that numbe of dB).
>
> 73,
>
> Jim Brown K9YC
>
>
>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|