Re: NEC-LIST: Design of Compact Range

I just finished building one. From scratch.

Next time I'd rather BUY one:-) Biggest headache: finding nylon
screws/nuts.

The specular reflections are the toughest part. If the ratio of
distances (reflection/direct) is large enough, you can get away with
NO anechoic material--unless you want 30 dB or more attenuation--which
is real tough. The floor reflection only has a ratio of about 3:1 but
by using a yagi at the reference port the reflection falls way outside
of the yagi's main beam.

I used intermark ferrite sheets for the turntable, each gives about 4
dB attenuation or more. The turntable is black plastic and passed the
microwave oven test easily.

Again, using yagis for the reference antenna. Note that I am only
using the range for differential measurements, usually against a
dipole.

A VERTICAL range has the virtue of only ONE specular reflection--at
least outside. I was tempted, but realized that the ceiling gave a
worse reflection than the floor, so that was that.

73,
Chip N1IR
Received on Mon Jan 17 2000 - 05:24:57 EST