"Richard Clark" wrote in message
...
On Wed, 29 Sep 2004 04:15:57 GMT, Richard Clark
wrote:

More on this below.

It seems in my effort to find the page(s) associated with HP and your
equipment, I forgot to expand on the issues promised.

The antenna is generally known as a "shielded, balanced dipole." This
is often applied to receive applications. For the dimensions you
suggest (halfwave overall length), the Z multiplication would indeed
present a 6:1 mismatch - on average.

To answer your question about what Z would be present at the "feed
point": it would fall along the circumference of a constant SWR 6:1
circle (speaking of a Smith Chart solution) depending upon the length
of the electrical distance to the true feed point. This will be
greater than the halfwave of the antenna structure given that its
electrical length is not confounded by insulation properties.

I have seen this design used for repeaters, but in a 4 bay
configuration. Undoubtedly the harness feeding it was composed of
halfwave sections placed in parallel to draw down the mismatch (at
least it acted like this, the wiring was hidden within the greater
supporting structure).

73's
Richard Clark, KB7QHC



Thanks, Richard.

John