"ml" wrote in message
...
Just wondering i am putting a dipole on the roof of a 12 story building
i'll mount it around 30ft off the flat surface of that roof

my antena will be about 150 ft off the sidewalk


when trying to calculate my dipoles hight is it above the roof surface
or 'real' earth /sidewalk ground that 'counts'??

thanks

===========================

Just take the geometric mean.

Effective Height = Sqrt( 150 * 30 ) = 67 feet.

But what you do with this number hardly matters two hoots. What do you have
in mind to use the number for?

Just continue to do as you intend and I'm sure the antenna will work fine.
It's very few people who have a starting point of 150 feet.
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Reg.