On Fri, 03 Oct 2008 14:47:12 -0700, Roy Lewallen
wrote:
...You might be able to live with the
common mode current. Otherwise, a larger diameter air-insulated sleeve
or some other decent isolation method like a J-pole are about all I know
of that would reduce it. Even those methods, though, can result in some
common mode current depending on the feedline length due to mutual
coupling between the feedline and intentionally radiating part of the
antenna.

The large-diameter sleeve is impractical in my app because it make the
antenna non-flexible for storage. Also expensive.

My principal use will be QRP. I will stick some ferrite beads on the
feedline and hope for the best.

The most I would use non-QRP would be 25 watts SSB.

Ken KC2JDY