On Feb 5, 3:06 pm, 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.

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?

DD

If you are wanting to make a coaxial collinear using solid metal tube
(copper? aluminum?) for the elements, why not just make that tube the
outer conductor of coaxial sections. The inner conductor can be a
piece of solid copper wire, that then connects to the outer conductors
of the adjacent sections. Or maybe that's what you mean; it's not
really very clear to me.

Be aware that the phasing of the coaxial collinear is controlled by
the electrical length of the coaxial sections. For a "flat pancake"
pattern they should be an electrical half wave. Depending on the
insulation, that may be considerably shorter than a freespace half
wave. That does not directly matter to the antenna; non-resonant
antennas work just fine. The feedpoint impedance will be the parallel
combination of all the feedpoints (assuming low loss electrical half-
wave connecting sections), transformed by any coaxial stub between the
last feedpoint and the feedline. The "feedpoints" are all the gaps
between sections.

Cheers,
Tom