Make a scaled drawing of the tower and roof (and surrounding buildings).
Draw lines downward from the antenna position at different angles, say
5, 10, 15, 20, 30 degrees, until they intersect the ROOF, other
buildings,
or Ground.
The effective height of the antenna is the difference between the
antenna height and the REFLECTING Height, assuming a level
reflecting surface.
Tom N4KG
On Thu, 18 Apr 2002 "Nat Heatwole" <nat@ajheatwole.com> writes:
> Is there any reliable way to tell what the "real" height of a yagi is
> that's on top of a building? In other words, electrically how high
> the antenna thinks it is. Is there a formula to calculate this if one
> knows all of the critical information (dimensions of the building,
antenna
> height above building, etc.) and assuming that the building is a 3D
> square or rectangle? Are there any rules of thumb for this or is
> modeling the only way?
>
> 73, Nat, WZ3AR
> <nat@ajheatwole.com>
>
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