Topband: 160 m inverted L

[Bob K6UJ]

David,

Thanks for sharing the study.
I am trying to digest it.  Need to go through it again.
He says:   " There is an optimal height for an elevated groundplane, 
that height is not at ground zero, and is typically around 0.05 
wavelength. (The statement the higher-the-better is not always true for 
such systems.) "

This figures to a little over 15 feet above ground for 160M.   I can 
manage that.
I think he has another study for the added efficiency with a ground 
screen under elevated radials.
I want to find that one too.

Bob
K6UJ

On 11/9/16 9:04 AM, David Cutter wrote:
> Hello Peter
>
> I haven't done any work on this, but Ralph has.  Have a look at this 
> site and others of his:
> http://www.arising.com.au/people/holland/ralph/shortvert.htm
>
>
> David
> G3UNA
>
>
>
> ----- Original Message ----- From: "Peter Voelpel" <dj7ww at t-online.de>
> To: <topband at contesting.com>
> Sent: Wednesday, November 09, 2016 4:57 PM
> Subject: Re: Topband: 160 m inverted L
>
>
>> Think of a dipole close to the ground, it will not be efficient with all
>> that coupling to earth and resulting losses.
>>
>> 73
>> Peter
>>
>> -----Original Message-----
>> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of David
>> Cutter
>> Sent: Mittwoch, 9. November 2016 17:37
>> To: Mike Waters; Rob Atkinson; topband
>> Subject: Re: Topband: 160 m inverted L
>>
>>
>> I recall reading from Ralph Holland that 0.015 wavelength was a good 
>> height.
>>
>> David
>> G3UNA
>>
>> ----- Original Message ----- From: "Mike Waters" <mikewate at gmail.com>
>> To: "Rob Atkinson" <ranchorobbo at gmail.com>; "topband"
>> <topband at contesting.com>
>> Sent: Wednesday, November 09, 2016 4:11 PM
>> Subject: Re: Topband: 160 m inverted L
>>
>>
>>> Fifty feet?! That means the feedpoint --the bottom of the antenna-- 
>>> would
>>> be 50 feet up! Do you know how high the top would have to be? I don't
>>> agree
>>> with that at all. And I've never heard of anyone who ever did that.
>>>
>>> The four elevated radials in these tests were just 16 feet high! And 
>>> what
>>> is more, the frequencies were 1490, 1450, 1240, and (maybe) 625 KHz.
>>> Almost
>>> as effective as 120 buried radials.
>>> lists.contesting.com/_topband/2007-11/msg00248.html
>>>
>>> I forget the radial height in Rudy Severns' (N6LF) tests, but IIRC they
>>> weren't anywhere near 50' high.
>>>
>>> My two elevated radials were 10' high. I know that a little higher 
>>> (and a
>>> few more of them) would have been better, but I can tell you that that
>>> 160m
>>> inverted-L WORKED! And I'm by no means the only one. :-)
>>>
>>> 73, Mike
>>> www.w0btu.com
>>>
>>> On Wed, Nov 9, 2016 at 6:10 AM, Rob Atkinson <ranchorobbo at gmail.com>
>>> wrote:
>>>
>>>> The rule of thumb for effective elevated radial height is 1/10
>>>> wavelength,
>>>> so on 160, around 50 feet up.
>>>>
>>>> 73
>>>>
>>>> Rob
>>>> K5UJ
>>>>
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