HH wrote:
I would like to know what the actual OD is of schedule 40 PVC tubing.

http://www.gizmology.net/pipe.htm

....scroll down a little less than half way. It turns out it's the same
OD as steel pipe of the same size.

I am building a NVIS dipole for 3.6 & 7.2 Mhz
I know what the wall thickness is and the nominal size, but say for instance
the OD of 1 1/2" schedule 40, is it really the OD they are measuring?

Here in Australia we have a quaint method of measuring structural steel pipe
where the OD is nothing like the size its listed at.

For example 3/4" pipe is actually 1 1/16 OD!! Give or take the wall
thickness, but its still known as 3/4" pipe!

There's a short but interesting story behind that on the link above.

73,
Galen, W8LNA