Topband: Are stacked verticals feasible?

Fri Sep 6 22:52:24 EDT 2013

Mike,

This is the book.

http://store.cq-amateur-radio.com/Detail.bok?no=26

73, Tony K4QE

On Fri, Sep 6, 2013 at 10:41 PM, Mike Armstrong <armstrmj at aol.com> wrote:

> Carl and Charlie,
> I am not sure it would even be close to practical or even doable, but I
> remember seeing an old book on verticals written by a prior Navy Captain, I
> believe.  He had a very interesting design for what WE would, today, call a
> collinear that was 3/4 wave length tall on 20 meters..... it was, in
> reality what looked like half of a double-zepp antenna in a vertical
> orientation. It intrigued me that it was like a half wave stacked on top of
> a 1/4 wave worked against ground (normal radial field). The interesting
> part was how he used a "skirt" around the "middle" quarter wavelength
> portion to produce the the in-phase relationship with the physically lower
> 1/4 wave.
>
> You guys may already know the design I am talking about.  I saw that book
> a long time ago, like back in the late 60's I think..... maybe early 70's.
> I was considering trying to find the article or book whenI was looking for
> a better vertical for my winlink node on 20 meters..... the one I have been
> talking about.  However, I tried the 5/8ths first because I knew how to
> build one without having to possess any special instructions.  It was so
> successful, that I completely forgot about the "collinear."  On the other
> hand, this discussion reminded me of that book and how author "raved", a
> little anyway, over its performance.  I remember that the height of the
> finished antenna for 20 meters was something very close to 50 feet......
> and that is not much taller than a 5/8ths..... maybe 7 or 8 feet taller.
>  So on 20 it is very doable and, supposedly, it has some reasonable gain
> for the effort.  I would like to find the book because it described a good
> way to make that all-important s
>  kirt that got the phase correct between the upper half-wave and the lower
> quarter-wave sections.  Due to its relatively tall structure, it probably
> wouldn't even be "possible" to build one for 160..... at least not by most
> of us.  It would be interesting to see if it has the same "problem" that
> Tom was referring to for the 5/8ths..... "too low" radiation angle.  I know
> it isn't supposed to have that secondary lobe that a 5/8ths has...... So
> maybe it would be an improvement ..... IF it was even possible to build
> one.  That would be one tall structure on 160.... LOL LOL. Still, for
> someone needing an omni antenna with some gain on the higher HF bands, it
> might be a decent answer.  Never built one, so I really don't know if it
> really works or not.  Although, as I said, that author was a Navy Captain
> whose job was designing some of the shipboard antenna systems, like the
> NORD and some other odd ducks.... Well, "odd" to those who don't have to
> build low loss, low band antennas on
>   a floating "postage stamp."  I know, I know, you might have trouble
> thinking of something the size of an Aircraft Carrier being referred to as
> a floating postage stamp, but if you have spent any time at sea on a "big
> deck," you know exactly what I mean by that statement...... he he he he.  I
> really should remember his name, darn it..... with all the time I spent on
> ships at sea working with his designs, it is really sad (bad?) that I don't
> remember his name...... Paul "something?"  I'll find out..... lol
>
> Mike AB7ZU
>
> Kuhi no ka lima, hele no ka maka
>
> On Sep 6, 2013, at 19:03, "Charlie Cunningham" <
> charlie-cunningham at nc.rr.com> wrote:
>
> > Well, Carl
> >
> > You just proposed a total height of 3/4  wavelength, it seems. Do you
> have
> > that much height?
> >
> > Charlie, K4OTV
> >
> > -----Original Message-----
> > From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of ZR
> > Sent: Friday, September 06, 2013 9:26 AM
> > To: Shoppa, Tim; topband at contesting.com
> > Subject: Re: Topband: Are stacked verticals feasible?
> >
> > Look at it as 2 ground planes with the lower feed point 1/4 wave above
> > ground along with its elevated radials which should make it pretty much
> > ground independent according to what has been published on here and
> > elsewhere.
> >
> > The second ground plane would be identical with 1/4 wave spacing from the
> > top of the lower antenna or a 1/2 wave between feed points.
> >
> > Then I would think that the ground conductivity at the reflection point
> > would be the only concern as far as efficiency and gain??
> >
> > If installed as vertical dipoles then there would also have to be
> additional
> > spacing between them.
> >
> > I would think that at 6-12' spacing from the tower it would minimize
> > interaction on 160 or 80?
> >
> > Does anyone on here have EZNEC and can plot this?
> >
> > Carl
> > KM1H
> >
> >
> >
> > ----- Original Message -----
> > From: "Shoppa, Tim" <tshoppa at wmata.com>
> > To: "Carl" <km1h at jeremy.mv.com>; <topband at contesting.com>
> > Sent: Thursday, September 05, 2013 10:30 PM
> > Subject: Re: Topband: Are stacked verticals feasible?
> >
> >
> >> Isn't this a "Vertical dipole"? Two quarter wave radiating elements? And
> > tower behind it will be some kind of reflector/director depending on
> height.
> > The radials seem unimportant if thought of this way.
> >>
> >> Tim N3QE
> >> ________________________________________
> >> From: Topband [topband-bounces at contesting.com] on behalf of Carl
> > [km1h at jeremy.mv.com]
> >> Sent: Thursday, September 05, 2013 9:17 AM
> >> To: topband
> >> Subject: Topband: Are stacked verticals feasible?
> >>
> >> Assuming that sufficient tower height was available, guy wires are
> > insulated
> >> or broken up into short non-resonant sections. Tower face is 12 or 18".
> >>
> >> Start at 1/4 wave up with a 1/4 wave ground plane with radials sloping
> at
> >> about 45 degrees. The vertical wire is 6-12' away from the tower face.
> >>
> >> Then a 1/4 wave (or 1/8) up install a duplicate.
> >>
> >> What does EZNEC say about this?
> >>
> >> With the different spacings?
> >>
> >> Effect of starting lower and how low before there are ground related
> >> problems?
> >>
> >> Phasing with coax or a LC network?
> >>
> >> Switching in a delay line to tilt the lobe up a bit?
> >>
> >> Curiosity got the cat!
> >>
> >> Carl
> >> KM1H
> >>
> >>
> >>
> >>
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