On 28 Jul 2008 04:03:29 GMT, Ed
wrote:

About as well as it flows up the center conductor, possibly. You
don't think that just because the cable is buried that RF flow on the
shield conductor is prevented, do you?

Hi Ed,

I think Jonesy is fairly safe in his presumption. The classic work
performed by Brown, Lewis, and Epstein pretty conclusively reported
the nearly complete attenuation of direct driven RF currents in ground
radials at 3MHz.

75 feet of buried shield would seem to be quite snubbed by the
proximity of earth over much of the range of frequencies reliably
operated from a multi-band HF vertical.

Of course, adding a choke can't hurt.

73's
Richard Clark, KB7QHC