[time-nuts] New NTBW50AA
Charles Steinmetz
csteinmetz at yandex.com
Sun Sep 15 19:04:00 UTC 2013
Dave wrote:
>Well, I could try it down on the fence, but like I say when I get
>down there, I'm not sure the visibility above the trees is any
>better to the east and west because it's so much lower and the trees
>are all 80' high or more.
It's not just the height of the trees, it's the horizontal distance
from the antenna location to the trees, too -- the elevation angle
above the antenna location (elevation = arctan (tree height/distance
to trees) (in this case, "tree height" means height of the trees
above the horizontal plane of the antenna, so it includes any
difference in the ground height at the tree location, as well).
At the end of the day, you want the most open sky you can get,
particularly the southern hemisphere of sky, but the lowest
elevations (say, under 20 degrees elevation) are not nearly as
important as 20 through 90 degrees.
Best regards,
Charles
More information about the Time-nuts_lists.febo.com
mailing list