Posted by
Lyn WØLEN on
Mar 13, 2020; 7:49pm
URL: http://elecraft.85.s1.nabble.com/Off-Topic-Your-advice-suggestion-about-antenna-tp7658892p7658901.html
Dave -
I actually do consider 4.7 dbi as "far outperforming" 2.14 dbi (ordinary dipole).
And since cost is an issue for some of us (along with HOA restrictions), I rejected the idea of getting a couple extra dbi at the cost of many thousands of dollars. And adding a N-S 40m dipole fed at the same point would have required either traversing my neighbor’s yard, or erecting a 2 towers … neither of which is feasible.
And forget the logistics of erecting a 2 element beam for 80 meters (see OptiBeam OB2-80+ with 74 foot elements on a 36 foot boom), tower and rotor for that monster.
We have a commercial (HST) shortwave station a few miles away that runs a 20kw transmitter on various 7 - 10 MHz frequencies into an 18 dbi gain "curtain" antenna aimed over the pole to Europe. Their beam width is 38º. Ten curtains could be hung using relatively inexpensive towers or masts spaced at 36º in a circle. The 20kw input results in an ERP of 808 KW, according to their FCC license, at an extremely low angle of radiation, and very low maintenance.
That would actually be my first choice.
73
Lyn, W0LEN
-----Original Message-----
From:
[hidden email] [mailto:
[hidden email]] On Behalf Of David Gilbert
Sent: Friday, March 13, 2020 1:39 PM
To:
[hidden email]
Subject: Re: [Elecraft] Off-Topic: Your advice/suggestion about antenna
That is certainly a perfectly viable antenna and probably a fine choice
for your needs ... but it does not "far outperform" either a dipole or
especially a 2 element yagi at the same height. (although the yagi would
of course be unidirectional). 4.7 dbi is dipole territory. You could
have gotten pretty much the same result with an E-W 80m dipole and a N-S
40m dipole fed at the same point (orthogonal fan dipole). And assuming
you used capacitors for the EDZ, dipoles are easier to build.
73,
Dave AB7E
On 3/13/2020 11:19 AM, Lyn Norstad wrote:
> Duane -
>
>
>
> I am of the mind that the antenna is the most crucial part of any station,
> and probably the most often maligned. I have made a number of presentations
> to ham groups on the design and construction process involved in getting
> the most bang for the buck, depending on your wants and needs (everybody's
> are different).
>
>
>
> In my own situation (2 acre semi-rural lot approx.150 feet x 600 feet
> running E-W feet, and active HOA) the goal was to have a single antenna that
> would provide the best primary signal on 80 meters in a North-South
> direction, while providing the best possible signal on 40 meters in an
> East-West direction, consistent with the 80 meter performance and without
> unduly provoking the HOA (or my XYL).
>
>
>
> I decided on an Extended Double Zepp, cut for 3.5 MHz. That resulted in a
> length of 360 feet, which worked nicely since I have 400 feet clear from the
> house (West end) to a perfect tree for the far East end. And another tree
> in the center for support of both the antenna and the feedline.
>
>
>
> I am feeding it with a 160 foot length of 600 ohm "true ladder line." I can
> go into more detail if this sounds like something that would work. Modeling
> this antenna with EZ NEC shows a maximum theoretical gain of 4.7 dbi in both
> North and South directions. With the ladder line, a dual hybrid balun and
> short length of coax into the shack, my KAT500 tunes it very nicely on all
> bands 160 m thru 6m.
>
>
>
> I don't have your call so can't see where you are, but would be happy to
> make other suggestions based on the coverage you seek.
>
>
>
> 73
>
> Lyn, W0LEN
>
>
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