Just wanted to drop a little note from my limited personal experience.
I have been involved in the construction of 2 weather protected open
area test sites. They were both built quite differently from each
other and the both meet the NSA numbers for both horizontal and
vertical polarization.
The first site built is for 3m testing only. It is constructed using
Post and Beam with as few nails as possible. The entire building is
outside of the three meter ellipse and the ground plane covers the
entire interior surface of the building. This site is built on a slab
so the support equipment and test equipment also occupy the building
but are well outside of the ellipse.
The second site can do both 3 m and 10 m indoors. The building is of
normal frame construction with plywood walls. The building is outside
of the 3m ellipse but most of the walls are inside the 10 m ellipse.
It has a full basement for measuring equipment and support equipment.
This site also had no problems meeting the NSA requirements for bit 3
m and 10 m.
From building these two sites I have two hints for you.
1. You need a near to continuos ground plane. That means use lots of
screws or what ever method you want to tie the ground plane sections
together.
2. Use dipoles for your site attenuation. Their antenna factors seem
to be more reliable than even recently calibrated broad band antennas.
These opinions are my own of course.
Tom Whissel
Compliance Engineer
Cabletron Systems, Inc..
[email protected]
(603) 337-2862
