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Old May 24th 07, 05:21 AM posted to rec.radio.amateur.antenna
KEYCLOWN AUCTION RATOUT CENTRAL KEYCLOWN AUCTION RATOUT CENTRAL is offline
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First recorded activity by RadioBanter: May 2007
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Default VHF Ground plane radials

On May 24, 1:14 am, Rick wrote:
If the ground radials go from 45 degree sloping downward to straight
horizontal, at what point does it become a ground plane and not a dipole?



Roy Lewallen wrote:
The antenna you're describing is a dipole. Half of the dipole is the
upper vertical wire. The lower half is the radials. Changing the length
of one half has the same general effect as changing the other half.


Roy Lewallen, W7EL


David Harmon wrote:
When making the standard VHF-UHF ground plane antenna as illustrated in
all the books, with four ground radials sloped down at a 45 degree
angle, are those radials a tuned length? How much difference would it
make if they were some random length considerably longer than specified?
(as, for example, using the antenna on a different band by merely
changing the center vertical element.)- Hide quoted text -


- Show quoted text -


The antenna is not a dipole unless it has only one "radial".
A ground plane is just that...several radials sloping and creating the
surface seen by the vertical element.