[TowerTalk] Tall verticals
i4jmy@iol.it
i4jmy@iol.it
Wed, 10 May 2000 17:32:23 +0200
Generally speaking, a vertical whose electrical height is up to 225
degrees has no theorical limitations to work efficiently.
Up to 120/130 electrical degrees (about 80-90 ft. for 80 meters)a tower
is still an excellent performer and the involved impedance doesn't
complicate too much the cables decoupling and the matching network.
73,
Mauri I4JMY
> ---------- Initial message -----------
>
> From : owner-towertalk@contesting.com
> To : <towertalk@contesting.com>, <n4kg@juno.com>
> Cc :
> Date : Wed, 10 May 2000 09:56:43 -0400
> Subject : Re: [TowerTalk] Tall verticals
>
>
> > > You specified "tall" towers. What about a 65 foot Rohn 45
> > > tower with tri-banders at 45 and 70 feet? Would the side-
> > > mounted beam problem be as pronounced on that?
> > >
> > Probably NOT. It should work OK on 160.
> > Forget 80M. Use a separate vertical.
>
> So, it would be about a 1/8 wave on 160?
>
> Why would it not work as a 1/4 wave on 80m?
>
> If I insulate the side-mounted beam by covering the mast with
> PVC will its proximity, even if electrically islolated, cause a
> problem?
>
> 80m is far more important to me for emergency communications
> than is 160m. Are there changes in the configuration of the
> tower and antennas that would make it more suitable to 80m
> use? Must I eliminate the side-mounted beam entirely?
>
> > > I want to load it for 80m and want to make some choices
> > > about the type of base I use, where and how I side-mount
> > > antennas and anything else that may impact performance on
> > > 80m. I have the tower but the pouring of the base has yet
> > > to be scheduled.
>
> - Thanks! & 73, DavidC K1YP in Hudson, FL
>
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