Richard,

You forgot to tell him about trimming the folded back coax shield in
order to account for the reduction in velocity factor. The folded back
shield and the coax outer shield have a dielectric constant between
them that is based on the cable jacket material and a minimal air gap.

You covered this quite well in an earlier post you made:

http://www.archivum.info/rec.radio.a.../msg00373.html

The original posters idea was easy to build and will work quite well
horizontally or vertically. He should put an RF choke (coax coil or
ferrite beads) near the feedpoint in order to reduce the RF flowing on
the outside shield of the cable.

Roger





Richard Clark wrote:
On 29 Nov 2006 12:42:43 -0800, "Dave" wrote:

Any and all (well, most, at least) comments will be given
their appropriate attention. Thanks.

Hi Dave,

Sounds like a lot of work when gravity can do most of the fiberglass
poles' job. Try a sleeve dipole (vertical, of course):

Take a coax and strip off 16.5 feet of its jacket;
Pull back the coax shield over itself (like taking off a sock from the
top) back to the 16.5 foot mark and keep pulling it another 16.5 feet;
You now have an exposed inner conductor, and the coax shield rolled
over 16.5 feet of jacketed coax (you need at least 33 feet of coax to
do this). Feed this prepared coax with more coax (or simply use a
very long coax with one connector at the transmitter).

This is where gravity comes to work:
Hang the inner/outer prepared coax over the end of the horizontal
support, with the feed tracing along the horizontal support.

Same amount of wire, no need for the fiberglass and even if you may be
closer to the waves, it hardly matters (unless you have 20 foot surf
conditions).

73's
Richard Clark, KB7QHC