PVC is not lossless, however...

I used PVC drainage pipe (white, 3 mm thick maybe) to make radome for 900MHz
antenna. Specifically, directional patch arrays. It tuned them down a little
bit (2 mm maybe over half-wave length.) I did not measure significant
decrease of gain. The cover did not touch the radiator. When it touches,
loading get significantly worse.

Andrey


It"Alex" wrote in message
...
On Tue, 14 Sep 2004 10:23:18 -0500, "Crazy George"
wrote:

Who told you PVC was lossless? Stick a sample of it in a (2.4 GHz)
microwave oven and see what happens. You could
simulate it with a sheet of carbon impregnated foam, but I guess 4nec2
doesn't handle that either. If you need a
radome, use foam polystyrene, commonly known as Styrofoam®.

many tnx for your answer

actually I am using styrofoam already for the indoor model. But
styrofoam is too soft and vulnerable to make weatherproof so I shall
have to put it in a case made of something more rugged.

Evidently 4nec2 does not handle the needed simulation so I shall look
around for other software or maybe make a SWR meter and some practical
experiments...

Alex