Cecil Moore wrote:

Cut two 1/4WL sections of tubing. Slip one over the coax and
connect it to the coax braid where the coax enters the
tubing. Leave the outer insulation on the coax. Don't connect
the bottom tube or the coax braid to anything where the coax
comes out. Install an insulator/support to hold the two pieces
of tubing together in a straight line dipole-like configuration.
Tie the coax inner conductor to the upper tubing. With this
configuration, you won't need additional choking on the feedline.

*******************+ ********************+
| ====================+========
1/4WL +--------------------------------- coax
| ====================+========
*******************+ ********************+

*** is the tubing, + is a connection.

I don't understand how this would work. The tube to coax connection
on the right seems to extend the 1/4 wave tube indefinitely, down the
line. I think I would connect the coax shield to the right tube at
that tube's left end, and add a ferrite current balun around the coax
where it exits at the right end of that tube.