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Re: Topband: Optimal radial wire type and gauge?

To: "DAVID CUTHBERT" <>, "Rick Kiessig" <>
Subject: Re: Topband: Optimal radial wire type and gauge?
From: "Tom W8JI" <>
Reply-to: Tom W8JI <>
Date: Sat, 15 Dec 2012 19:10:09 -0500
List-post: <">>
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 -

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