"
Richard,
I haven't seen anything like that sold commercially,
but I don't see why you couldn't make one. Ought to be
able to find a source of plastics on the internet or
locally, maybe. Drill the holes you need and half way
there.
'Doc

What material do you think?


As the center of a dipole is low impedance almost any insulator will work.
If mounted outside pick something that will withstand the sun.