I don't think an insulator would make much difference for this problem but
you should be using one anyway.

--
Jim
N8EE

Makes BIG difference. You have high RF volatge point at the ends, you need good
quality insulator that doesn't absorb water (like rope) or melt under RF. It
helps to make small loop of wire, so it is terminated in "capacitor" plate
rather than sharp wire end (had that problem with balloon vertical).
Situation gets worse in salty air environment, where rope becomes conductive
when soaked with moisture and salt. Loop made of plastic ties works OK as
insulator, rope tied directly to the end of wire is a NO-NO!

Yuri,
www.K3BU.us
www.computeradio.us - home of Dream Radio One