On Nov 7, 9:49 pm, Owen Duffy wrote:
wrote roups.com:



An alternative way to view your antenna is a large metal ground plane
with the vertical mounted on it and fed 24" up from the base. In that
case, resonances would be lower than expected, explained by the
vertical being 24" longer than design.

Gee, it makes obvious sense, now that you say it. Guess I don't have
to be
afraid of cutting the tubes now.

It is not obvious that you need to cut more than the lowest tube.

Remember, measure twice, cut once...

Owen

The coupling to the steel roof pulls the traps out of resonance...
Call Hustler ... They have an updated tuning schedule for the 6BTV...
I don't have mine here at the office or I would offer it to you...
I found the 6BTV to be impossible to get tuned properly - even when
ground mounted per their instructions...
The answer - after I called them - was in tuning the traps along with
the length of the sliding sections... Their updated tune schedule
explains how to do it...

If after tuning the traps you have problems still, then I would
suggest an insulated mount with insulated-wire radials laid on the
roof... Put tape on the ends of the radials so they don't arc...
denny / k8do