[TowerTalk] Gain of a Horizontally Polarized Dipole

[Frank Donovan]

Roger,

Because height above ground affects feedpoint impedance as well
as providing -- ideally -- 6 dB of ground reflection gain, the actual
gain of a horizontal half-wave dipole can be nearly one dB better
than the 8.15 dB you suggested at certain elevation angles.

An excellent reference on this topic -- based on actual measurements --
was published in IEEE Transcactions on Antennas and Propagation, July
1967, pp 569-571.

To summarize the article, the following heights provide over 9 dBi of gain
for a horizontal half wave dipole over perfectly conduction soil.  Gain of
a horizontally polarized dipole drops only 2 dB (to 7 dBi) when placed 
over poorly conducting soil.

Height in      Elevation Angles
Wavelengths    exceeding 9 dBi
0.6                16-30
1.1                10-16
1.6                 7-11
2.1                 5-8
2.6                 4-6

73!
Frank
W3LPL
donovanf@sgate.com

On Sun, 19 Oct 1997, Roger D. Johnson wrote:

>  If you use an isotropic radiator for the reference and add in 6 db
> ground reflection gain , it's possible for a dipole to have 8.15 db
> "gain" by itself!
> 
> 73, Roger


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