On Wed, 06 Feb 2008 01:54:21 GMT, "Jerry"
wrote:


"Richard Clark" wrote in message
.. .
On Tue, 5 Feb 2008 15:06:40 -0800 (PST), Dave99
wrote:

OK thanks... Actually I was reading something that indicated you
should add in a velocity factor for the tube when using it as a
sleeve. I had never heard of that either, so I wasn't sure. They used .
95 I believe.

Hi Dave,

I presume you mean 0.95, which for a metal tube holding an inner
conductor that is air insulated, then that might be operative. Too
much is left unsaid: like frequency/wavelength, size of tube, any
inner conductor (so as to emulate a coax), any coax within the tube
(to further compound the issue), the length of tube.... in other
words, a lot of missing details. Some are suggestive in your use of
the term sleeve, but you don't provide much to help.

So I guess you would go coax center conductor to tube section #1,
braid to center of second coax through section #1 to section #2. Coax
from section #1 through section #2 to section #3 and so on?

So, what is #1, #2, #3, and so on? I get the impression you have a
vivid image of this in front of you, but you are blocking the view and
I can't see it.

73's
Richard Clark, KB7QHC

Hi Richard

Is it possible that dave is considering one of these
http://www.nodomainname.co.uk/Omnico...4collinear.htm ?

Hi Jerry,

Now that you mention it, it does resemble the #1, #2, #3, and so on -
so described. This is also known as a Franklin Array, but not in the
classic design. Problem here is that the phasing of the radiating
elements' exteriors are critical to the operation of the antenna,
insofar as gain goes. On the other hand, the wavelength dimension of
the inside of the same elements are critical to the operation of the
antenna, insofar as matching goes. That the two electrical
wavelengths might match and possibly work is a guess as the author
states:
"we chose LMR-400 as it was lying on the floor"

The commercial builders of the same style antenna use simple wire with
the occasional spacer.

73's
Richard Clark, KB7QHC