Again, see "waveguide beyond cutoff".
No signal will ever get inside of the tube unless there is a conductor
running out the opening to couple it in. then the signal will end inside
shortly after reaching the end of that conductor.
73
Gary K4FMX
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Dan Schaaf
> Sent: Wednesday, December 28, 2011 4:14 PM
> To: David Gilbert; towertalk@contesting.com
> Subject: Re: [TowerTalk] Trees and Verticals
>
> Let's go a step further,
> What happens if you put a dry wooden broomstick down the center of an
> aluminum tube vertical.
> Then a wet Broomstick.
>
> Best Regards
> Dan Schaaf
> K3ZXL www.k3zxl.com
>
> "Problems cannot be solved by the same level of thinking that created
> them." - Albert Einstein
>
>
> ----- Original Message -----
> From: "David Gilbert" <xdavid@cis-broadband.com>
> To: <towertalk@contesting.com>
> Sent: Wednesday, December 28, 2011 4:05 PM
> Subject: Re: [TowerTalk] Trees and Verticals
>
>
> >
> > That would be an interesting configuration to model in the manner that
> > Jim Lux suggested (using a set of resistive wires to simulate the
> tree),
> > but I'm pretty sure that the losses would be significant if the tree
> > itself was indeed lossy. Normally the fields inside a closed
> structure
> > are minimal, but that's because (unless I am mistaken ... which is
> > entirely possible) the E-fields generated by current through the
> various
> > wires/surfaces repel each other. If you put a lossy medium in the
> > middle they get absorbed before they repel each other.
> >
> > I'm guessing that would be the second worst way to use a tree as far
> as
> > efficiency is concerned. The worst would probably be to bore a long
> > hole down the center of the trunk and run the wire through it.
> > Stealthy, yes ... efficient, no.
> >
> > 73,
> > Dave AB7E
> >
> >
> >
> > On 12/28/2011 1:41 PM, Dan Schaaf wrote:
> >> What happens if you make the vertical as a cage of vertical wires
> around
> >> the tree ? Joined at the top and joined and fed at the bottom. The
> tree
> >> is in the center of the cage.
> >>
> >> Cage wire antennas seem to have a broad bandwidth. But what happens
> to
> >> the tree losses when the tree is caged ?
> >>
> >>
> >> Best Regards
> >> Dan Schaaf
> >> K3ZXL www.k3zxl.com
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
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