Tony, Thanks...,. that is the one. As I recall a very good book "from my
youth." It was one of the first antenna books that I remember reading in my
early ham years...... I think its original publishing date was after I was
first licensed (1960, when I was an ancient 8 years old... LOL). But it
couldn't have been too much later than that. Still in production...... Well,
that is a good sign :)
Mike AB7ZU
Kuhi no ka lima, hele no ka maka
On Sep 6, 2013, at 19:52, Anthony Scandurra <anthony.scandurra@gmail.com> wrote:
> 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@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-importan
t 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@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@contesting.com] On Behalf Of ZR
>> > Sent: Friday, September 06, 2013 9:26 AM
>> > To: Shoppa, Tim; topband@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@wmata.com>
>> > To: "Carl" <km1h@jeremy.mv.com>; <topband@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@contesting.com] on behalf of Carl
>> > [km1h@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
>> >>
>> >>
>> >>
>> >>
>> >> _________________
>> >> Topband Reflector
>> >> _________________
>> >> Topband Reflector
>> >>
>> >>
>> >> -----
>> >> No virus found in this message.
>> >> Checked by AVG - www.avg.com
>> >> Version: 10.0.1432 / Virus Database: 3222/6141 - Release Date: 09/05/13
>> > _________________
>> > Topband Reflector
>> >
>> > _________________
>> > Topband Reflector
>> _________________
>> Topband Reflector
>
_________________
Topband Reflector
|