Well, I think our course is now clear. Someone needs to put up a vertical
with 40 1/4-wavelength radials and make some detailed measurements. Then do
the same thing with 50 and 60 radials. Then see if there is any meaningful
difference in the results. We need measurements over sand, loam, salt
water, marsh land, and rocky terrain. I certainly don't want to miss any DX
just becuase the tips of my radials should have been (approximately) .005
wavelength closer together. And, I know Tom would not want any of us to
miss some good DX by being so horribly negligent.
Wes - N5WA
-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of Bill Coleman
Sent: Friday, November 02, 2001 8:53 AM
To: W8JI@contesting.com; Rick Williams; towertalk@contesting.com; Guy
Olinger, K2AV
Subject: Re: [TowerTalk] vertical antennas
On 10/24/01 8:32 AM, Tom Rauch at w8ji@akorn.net wrote:
>RCA spent a fortune on studying this, and they concluded 50-60
>1/4 wl radials acted like a solid plate. The key is to not let the open
>spaces exceed about .025 wl between wires. That even works with
>a screen reflector antenna!
I don't mean to disagree with Tom, whom I have the highest respect for,
but the math doesn't quite work out.
If you have 1/4 wl radials, you create a circle or radius 1/4 wl, with a
perimeter of pi/2 wl. (eg 2 pi r )
Now, pi/2 wl divided by 50 is pi/100 -- which is 0.0314159..., and pi/2
wl divided by 60 is pi/120 -- which is 0.02618. Close, but not quite
0.025.
That would tend to indicate you can have ultimate spacing a bit larger
than 0.025 wavelength -- perhaps as much as 0.030.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
--------- Wes Attaway (N5WA) ---------
2048 Pepper Ridge, Shreveport, LA 71115
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