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Re: Topband: Optimal radial wire type and gauge?

To: "'DAVID CUTHBERT'" <>, "'Tom W8JI'" <>
Subject: Re: Topband: Optimal radial wire type and gauge?
From: "Charlie Cunningham" <>
Date: Sun, 16 Dec 2012 19:29:38 -0500
List-post: <">>
Well, I suspect that one can't get a complete picture of the correlation
between base driving point impedance and radiated field intensity unless we
could measure at a multiplicity of elevation angles. Has anyone looked into
changes in the elevation pattern as the ground systems are modified? Much
easier said than done!!

Charlie, K4OTV

-----Original Message-----
From: Topband [] On Behalf Of DAVID
Sent: Sunday, December 16, 2012 8:06 PM
To: Tom W8JI
Cc:; Rick Kiessig
Subject: Re: Topband: Optimal radial wire type and gauge?

I think you are extrapolating one case with a particular radial length to
all vertical antenna ground systems.

The N6LF radial papers detail his NEC-4 simulations and measurements of
vertical antennas and radial systems. If I read his papers correctly base
impedance does track field strength measurements.

Dave WX7G

On Sat, Dec 15, 2012 at 5:10 PM, Tom W8JI <> wrote:

> There is no magic about 120 radials, and long before 120 radials are 
> reached the increase in field strength pretty much stops.
> At my house around 30 radials or so, about 1/4 wave long, go flat on 
> efficiency increase on 160 meters.
> I could have a million radials and it would be insignificantly 
> different than 30 radials when they are 1/4 wave long here.
> I found this by measuring field strength, and I also found feed resistance
> change did NOT necessarily track the field strength changes.     Good luck
> on using base impedance to determine effiency changes! In a 40 meter 
> test, for example, one ground system provided 35-40 ohms of feed 
> resistance and another different system that provided almost 60 ohms 
> of feedpoint resistance had equal field strength.
> I think N6RK and others have measured the same.
> 73 Tom
> ----- Original Message ----- From: "DAVID CUTHBERT" < 
> To: "Rick Kiessig" <>
> Cc: <>
> Sent: Saturday, December 15, 2012 10:49 AM
> Subject: Re: Topband: Optimal radial wire type and gauge?
>  Read the N6LF radial papers and you will see that 1/8 wavelength 
> radials
>> are about as good as one can do. I use #14 stranded copper THHN wire 
>> because it is easy to work with.
>> But how good can we get? For a 30' base loaded vertical I have 90 
>> radials having an average length of 18 ft. The ground loss is 5 ohms, 
>> which is less than the loading coil loss. If I were to install 120 
>> quarter wavelength radials I would gain 2 dB.
>>     Dave WX7G
>> ______________________________**_________________
>> Topband reflector -
Topband reflector -

Topband reflector -

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