The sleeve idea sounds interesting.

Could I build it out of say aluminum tubing, run the coax up the center
of the tube to some sort of insulator, shield connected to the braid and
center connected to a wire extending upwards? Could I build the top half
out of tubing as well or does the radiator need to be significantly
smaller than the sleeve?

de ka2pbt

Cecil Moore wrote:
Rob Roschewsk wrote:
Cecil Moore wrote:
How about a 1/2WL vertical?

OK. End fed?? How should I feed it? Ladder line like a Zepp??

I would center feed it with horizontal ladder-line
and use it on 20m-10m.

However, a 1/4WL sleeve on the bottom half would
allow you to feed it at the bottom with coax.

Another possibility is a matching network at the base.
Your ground rod might work OK with that.