"John Smith" wrote in message
...

"'Doc" wrote in message ...


Stephen Cowell wrote:

Plumber's Delight J-pole doesn't require
an insulator at all... I'd imagine that it could
take all the power you could pour into it,
probably take way over legal limit to melt
a half-inch copper pipe J-pole.
__
Steve
KI5YG
.

None at all? Are you real sure about that?
Think about it...
'Doc


Yeah, no insulators at all... using plumber's delight.

The bottom of the J is strapped together. The feed point is then moved up
from the bottom along the 1/4 wave matching section until a match is
obtained.

This approach can be pretty nice. I used three sections of steel mast for
a
30 feet tall pipe, grounded at the bottom for lightning protection. I then
added a 1/4 wave piece of conduit 3/4 wave down from the top strapped with
sheet steel. Made a 1/2 wave balun from coax and found the lowest SWR feed
point along the matching section. The entire arrangement was at earth
ground, so no floating elements. Some designs found in books and on the
Web
feed them directly without the benefit of a balun. I've done it both ways
and have had great success.

What keeps the mast below the J pole from radiating?
Dale W4OP