On Aug 16, 7:13*pm, Bob Bob wrote:
Hi Jimmie

Some years ago I made a 3 el 10M quad that was actually a bow tie
arrangement. ie the spreaders were "driven" and the side "elements" were
rope.

Probably not what you are thinking about but it did look like a 3 el 20m
quad! I should have modeled it in later years but never got around to
it. It worked okay at the time but I wasnt exactly doing any extensive
testing.

Does modeling the metal spreaders give you any ideas?

Cheers Bob

JIMMIE wrote:
I was talking with some guys this AM about building a quad antenna
using aluminum spreaders. I know that it at least the tips of the
spreaders would have to be made of insulating material such a
fiberglass but the consensus seemed to be that most of the spreaders
should be non-metalic. I was wondering if anyone here had built a quad
with almost all of the spreaders made of metal and what was the
results.

Jimmie

Ive never really gotten in to modeling antennas that much. Ill
probably just build something and see what happens.

Jimmie

On Aug 17, 12:48*am, JIMMIE wrote:
On Aug 16, 7:13*pm, Bob Bob wrote:



Hi Jimmie

Some years ago I made a 3 el 10M quad that was actually a bow tie
arrangement. ie the spreaders were "driven" and the side "elements" were
rope.

Probably not what you are thinking about but it did look like a 3 el 20m
quad! I should have modeled it in later years but never got around to
it. It worked okay at the time but I wasnt exactly doing any extensive
testing.

Does modeling the metal spreaders give you any ideas?

Cheers Bob

JIMMIE wrote:
I was talking with some guys this AM about building a quad antenna
using aluminum spreaders. I know that it at least the tips of the
spreaders would have to be made of insulating material such a
fiberglass but the consensus seemed to be that most of the spreaders
should be non-metalic. I was wondering if anyone here had built a quad
with almost all of the spreaders made of metal and what was the
results.

Jimmie

Ive never really gotten in to modeling antennas that much. Ill
probably just build something and see what happens.

Jimmie

I slid Al tubing over the supports for my two meter quad except for
the last two inches toward the tip and I cant tell any difference in
operation VSWR is the same. AGC voltage on my receiver is the same as
usual for a local repeater. Whether or not the boom ends of the tubing
were connected together also had no discernible effect.

Jimmie

Hi Jimmie

IME the most critical part of quad tuning is F/B so you might like to
use that as a go/nogo test for your spreader experiments.

My thinking on metal spreaders would be about their length with respect
to wavelength. ie if they started approaching resonance of the operating
frequency (incl coupling to boom etc) I would expect pattern/gain & feed
Z to be affected. I wouldnt try real hard mind you, just plug the think
into a NEC engine.

Good news though..

Cheers Bob


Jimmie

I slid Al tubing over the supports for my two meter quad except for
the last two inches toward the tip and I cant tell any difference in
operation VSWR is the same. AGC voltage on my receiver is the same as
usual for a local repeater. Whether or not the boom ends of the tubing
were connected together also had no discernible effect.

Jimmie