Jimmie D wrote:

Depends on the PVC you use. Some of it is pretty bad. Put a sample in a
microwave oven with a cup of water and turn it on for a couple of minutes.
If the plastic gets hot it is bad for antenna use.. Probably OK for supports
but I wouldnt use it to house an antenna element

That tells you the loss when in an intense field at microwave
frequencies. It doesn't tell you a thing about the loss near a typical
HF or VHF antenna, except that if it passes the microwave test it's
probably ok. Many materials which fail the oven test are fine for other
applications.

PVC insulation on wire won't hurt an antenna noticeably, nor will PVC at
low-electric field points like a dipole feedpoint. I'd avoid using it
for an insulator at high field points like the end of a wire antenna or
the base of an electrically short dipole.

Roy Lewallen, W7EL