Thread: Radials
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Old April 3rd 14, 01:23 PM posted to rec.radio.amateur.antenna
Wimpie[_2_] Wimpie[_2_] is offline
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Default Radials

El 03-04-14 1:04, escribió:
Ian wrote:
In ,

writes





The theoretical gain of a GP with horizontal radials, radials drooping
45 degrees and and drooping 85 degrees is 1.42, 2.22, and 3.67 dbi.

I would have thought that the 'ultimate' would be when the droop IS 90
degrees (ie essentially a sleeve dipole).

With a droop of 90 degrees, is the gain slightly more than 3.67?


You can't physically have a 90 degree droop. The radials would have to
extend horizontally for some distance, then drop to 90 degrees.

This is the same as saying, you can't have a 90 degree radiator, as
due to wind it will bend. You know that going horizontally a few inch
and then 90 degrees down doesn't make big difference compared to 85
degrees sloping. You only may experience some length difference to get
lowest common mode current in the mast or feeder. Both option will not
give you more gain compared to a half wave dipole (free space).

That is a different antenna.





How come that you can have a 1/4 wave radiator groundplane type of
antenna with a gain that is more than a halfwave dipole (2.15 dBi) -even
if it is more-or-less a sleeve dipole?


When the radial droop approaches 90 degrees it really isn't a GP antenna
anymore, it is something else.


Is this because of electrical operation (I doubt), or naming convention?




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Wim
PA3DJS
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