Just a cautionary note about the use of plastic tubes to support LF aerials.
Water collects inside the tube (if it is horizontal) and RF then tracks
along it and the whole thing catches fire... I know this! Mine was
separating my strapped feeder so the two ends were at the same RF
Funny stuff this RF.
For information I have used plastic electrical conduit, oval shaped and
cheaply available in various sizes, as spacers for open wire feeder. I do
not know how this plastic would cope with the kind of voltages at the end
136 antennas but it might be worth trying. Certainly it was the quickest
and neatest way to make feeder spacers, far better than old Biros!