Problem with a tree - line of site

[jazzyman]

I am considering setting up a dish, although I think I may have a problem with a nearby tree, around 30 metres distance from the dish location.

Using the Dishpointer Google Map obstacle line of site finder, quotes
d=31.1m
h=13.5m

The tree looks to be approximately 15-20 metres in height, if I was to locate the dish as high as possible on the building, approx 6 metres off the ground does the h=13.5m figure increase 6 metres? i.e. 19.5m.

[AlanSH]

Yes, h is measured from the bottom of the dish. So, if the dish is located 6m high, the tree must not be taller than 19.5m from the ground, or 13.5m from the level of the dish.