I have successfully constructed various 2400 Mhz antennas using the
4nec2 antenna modelling software (really great application, warm tnx
to the author should he read this!)

What I would like now is to get a rough idea as to how close I can put
the antenna elements to a PVC casing without disturbing the radiation
pattern, SWR etc.

E.g. by putting a 2 mm lossless PVC sheet (with dielectricity constant
= 7) 1 cm in front of the antenna element.

Is it possible to simulate this?

Alex