Thanks for the responses.

Tom, I didn't know that the feedline decoupling issues with J-poles
were so bad.

I'd be interested in more information about why it's such an issue.
Would a sleeve stub work better than an open wire stub? It's certainly
stupid to make the feedline MORE of an issue.

I like the sleeve/skirt decoupled dipole idea.

I hadn't thought about routing the feedline out on a sidearm. I was
thinking of doing that with the antenna, but with a large yagi it would
be a problem. Putting the feedline out a few feet and then dropping it
down to a lower point on the mast could certainly work.

As far as putting the feedline in the plane of the elements, understood
on the modeling and placement issues.

If one were to do this, would it help to have ferrite beads all along
the coax from the feedpoint to some distance down the mast? Of course
good feedline decoupling is important for any directional array, but I
imagine that a wire with a string of ferrite beads on it is pretty much
invisible to RF... is this right?

Maybe a long bead balun dropping away in between elements would be a
good way to go with no sidearms?

Thanks for the responses; I'd be interested in further ones.

73
Dan