[TowerTalk] Inverted L for 160 meters

[jeremy-ca]

----- Original Message ----- 
From: "Jim Brown" <jim at audiosystemsgroup.com>
To: <towertalk at contesting.com>
Sent: Friday, October 19, 2007 9:15 AM
Subject: Re: [TowerTalk] Inverted L for 160 meters


> On Fri, 19 Oct 2007 08:57:45 -0400, jeremy-ca wrote:
>
>>With 32 radials 12' high I never waited in pileups very long.
>
> What you have is a conventional radial system that happens to be 12 ft
> off the ground. My 160 vertical currently has 40 radials that are 70 ft
> long, and it works fairly well too. A true elevated radial system can be
> effective with as few as four radials.


A tree can be effective as an antenna also. It all depends upon what level 
of efficiency you are happy with.


What you are talking about is called a ground plane and has been around 
since the 30's. The original concept was to have the base at least 1/4 above 
ground.



>
> There's nothing WRONG with having radials 12 ft off the ground on 160,
> but they are not "elevated" radials, they act just like they were laying
> on the ground, because AS A FRACTION OF A WAVELENGTH, they are nearly on
> the ground.

Yes they are elevated radials, you are the only one Ive heard of that thinks 
otherwise.


>
>>Belrose and others have published also and believe that 12' is adequate
>>on 160 in many cases.
>
> I've read some pieces by Belrose and by the late Carl Smith on the
> subject, none of which say that 12 ft high radials can be considered
> "elevated" on 160.


Elevated & raised are terms that are interchanged. I wouldnt expect someone 
of Belrose's stature to set an exact height as a golden rule.


>
>>BC band engineers have proven that an elevated
>>system delivers the same field strength OR BETTER than a classic 128
>>buried radials at the same site.
>
> Perhaps you might cite the specific references in the literature that
> say that. The ones I've read don't say that.


I guess you can find them the same way I did; try Google. I'll even give you 
a couple of key words to assist. Elevated Radials; Unipole; Folded Unipole; 
Broadcast Antennas to name a few.

Carl
KM1H



>
> 73,
>
> Jim Brown K9YC
>
>
>
>
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