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radials

Apr 3rd 2012, 19:59

SIZE358

Joined: Apr 19th 2009, 19:30
Total Topics: 0
Total Posts: 0
On a 5/8 wave vertical antenna should the radials be 1/4 wave 5/8 wave or the longer the better ? Danny K5DRS
Apr 4th 2012, 00:25

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

The theoretical advantage of a 5/8 wavelength antenna over a quarter wave antenna requires a very large ground plane--the longer the radials the better. Studies have shown that the advantage goes away for small radial systems.

Zack Lau W1VT
ARRL Senior Lab Engineer
May 11th 2012, 01:32

N9AAT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I agree, the longer the better if you want a ground system. Shorter radials can become part of the radiating system itself. The radials for my multiband vertical are a ground plane for 10-15-20 with little affect on SWR (mostly angle). However, because of the length I've chosen they become "elements" on 40, which does directly affect my SWR. On 80-meters they don't seem to do me any good at all.

Try using the EZNEC programs to experiment. With that you can also raise your system up and down relative to ground.

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