[Elecraft] Another "dipole" with a simpler tuner and feedline

[Benny Aumala]

Inverted L for 20:

Have your horizontal lamda/2 wire fed at the other end.
Make the vertical feeding wire (single) the same length.
Voltage feed it on 20 and 40 meters with tuned circuit.
Current feed on 80 meters against 20 meter radial.

Horizontal wire on 10 meters height is at least 6 dB better for 20m band
than any simple vertical. But this antenna has some vertical radiation,too.
For 40 the radiation pattern is suprising good for domestic QSO and low
enough for some DX, too.
For 80 this is but a shortened top-loaded vertical with poor number of
radials, but it works.

Benny
OH9NB


On Tue, 3 Aug 2004 21:47:01 -0400, Guy Olinger, K2AV
<olinger at bellsouth.net> wrote:

> For a single band, there is an interesting old-time alternative called
> a single wire Windom. It is a horizontal halfwave with a single wire
> feedline connected to the horizontal wire off-center. For 20 the
> "dipole" part is 34 feet. The single wire feed is soldered to the
> horizontal at a point 12.5 feet from either end and drops to the
> ground.
>
> The wire is fed against ground. The single wire exhibits a 400-450 ohm
> feed against ground, regardless of the height of the height of the
> horizontal under 3/4 wavelength. The vertical part radiates very
> little. A poor ground that would ruin a vertical's performance at
> 20-35 ohms feed Z will do OK at 400-450 feed Z. As in a single 17'
> radial wire just laid on the ground.
>
> You can feed it with a unun wound on a toroid with a 3:1 turns ratio.
> SWR on the low Z side easily matches 50 ohms well enough for coax or
> any antenna tuner, without having to endure the high voltages found on
> an endfed halfwave.
>
> It has the predictable performance of a good dipole, without the
> center insulator, and without the weight of a coax feed. If you use
> something like flex-weave for all the wires it can be wound up and
> carried around.
>
> 73, Guy.

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