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Old June 14th 07, 09:23 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Sep 2006
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Default when does a vertical become vertical dipole?

On 14 Jun, 12:50, wrote:
On Jun 14, 1:33 pm, greg mushial wrote:
If a vertical dipole is 10 wavelengths above the ground,

does one still have to consider the ground as part of the antenna? how
about 2 wavelengths? If someone could walk me through a thought
experiment on this I'd appreciate it.


Any vertical that is complete, and is clear of the ground qualifies.
Even a 1/4 wave ground plane with radials.
No properly built elevated verticals rely on the ground to complete
the
antenna.
Of course, you can still be effected by ground loss though, if you
are low to the ground, or don't have enough radials for the height
in wavelength you are at.
But a horizontal dipole can suffer the same losses,

snip

Wrong......

There was a study in Australia where the earth's influence on a
horizontal
antenna showed where the earths influence disappeared rapidly. That
cannot be
said of a short vertical. If it was of full length ,as in dipole, I
suspect
the earth's influence would be the same as a horizontal antenna.
Note: horizontal and vertical referes to polarization not to physical
orientation of radiators