Yes, it's true.
For some years I used a fixed two elements wire yagi @200 ft (almost
straight elements), remotely tuning the passive element as a director or
a reflector.
Some precise open wire trasmission line and element lenght allowed a
remote capacitor to give the needed amount reactance and reverse its
sign. (-j +j)
The antenna pattern was good enough while bandwith was pretty small. So
far, the passive element had to be tuned precisely from the shack to
keep currents high in any portion of the band. Obviously, this feature
made the "split" operation a bit tricky.
Since the yagi impedance changes if the passive elements tunes as a
reflector or director (the spacing was 0.14Wl), and 1.8Mhz is a wide
band (must think about in percent), a flat match was impossible all over
the band and the antenna SWR was a compromise.
Most of the times, in the favourable headings, the antenna had the same
reception of a 660 ft terminated beverage, sometimes it was better,
someother worse.
While producing a big signal, receivers suffered because of the huge
signals of medium distance continental stations and for the same reason
it was not uncommon to sutruggle because of "splattering" and clicks.
(as you lower the antenna from ground below half wave, this problem rises)
Height from ground was (and remains) a key factor and it's not so easy
to keep the yagi elements far enough from terrain.
All considered, unless one has a peculiar situation to utilize, a
vertical tower as a transmitting antenna and a separate receiving system
(I'd suggest beverages) could be an easyer, but very effective approach
for Dxing on 160m.
73,
Mauri I4JMY
Il 10/09/2010 9.49, Pete Parisetti ha scritto:
> Top contest station IR4T in Modena, Italy, has a two element wire beam
> suspended from a water tower at 210'. Performance, as I remember from 15
> years ago, was astounding - once we managed to break the US pileup on
> 4U1UN...
>
> The design was the work of Maurizio, I4JMY, who I believe reads this list.
> You may want to contact him directly for more information.
>
> 73/DX
>
> Pete
>
> On Thu, Sep 9, 2010 at 9:18 PM, Craig Clark<jcclark@myfairpoint.net> wrote:
>
>
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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