[TowerTalk] Re: Radials over salt water

[Ken Hirschberg]

Hi all -
The traditional broadcast radial field has 120 radials because the radials go out
to 0.4 wavelengths, not 0.25.  BTW, if one would like the radials to behave  like
a solid screen, 0.015 wavelength maximum spacing between wires would be a good
number to use.
Yes ...that's a LOT of wire! (and a lot of performance)

 A somewhat more complex approach that would save some wire, would be to go out
with say, 30 radials until the 0.015 spacing between wires was obtained, connect
a circumferential wire to each radial, then add radial wires between the original
30 radials, from that ring outward.  When the spacing between wires again gets to
0.015, then add another ring, and so on, until the desired radial length is
reached.
73, Ken

Bill Coleman wrote:

> On 1/10/01 15:35, Tom Rauch at w8ji@contesting.com wrote:
>
> >> Thinking and analyzing the situation, there should
> >> be improvement if using many (>60) elevated (or on ground) radials vs. few
> >
> >Fact Yuri. When the radials are less than .025 to .05  wl apart at
> >the open ends, they look like a solid screen. Using more radials
> >than that is a waste of wire.
>
> Hmm. 1/4 wave radials means a circle of 1/2 diameter. That's a perimeter
> of pi/2 wavelength, which divided by .05 yeilds about 31 radials.
> Similarly, .025 spacing at the ends is about 63 radials.
>
> If >63 radials is like a solid screen, I wonder why there's so much in
> the amatuer literature about installations with 120 or so radials.
>
> Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
> Quote: "Not within a thousand years will man ever fly!"
>             -- Wilbur Wright, 1901
>
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