On Wed, 17 Feb 2010 20:54:15 -0800
"Richard (Rick) Karlquist" <richard@karlquist.com>
wrote:
>
>
> GEORGE WALLNER wrote:
>>
>>
>>
>> Niko Cimbur <ac6dd@yahoo.com> wrote:
>>> Can something like this be easily done?
>>> I am not familiar with the two 750W amps they have, but
>>> Would it be possible to build a 4 square and feed each
>>> element with its own amplifier and switched phase delay?
>>>
>>
>> Niko,
>>
>> I have done this with a two element array and it worked
>> great. Phasing control is much easier at low power
>>levels,
>> i.e. ahead of the amplifiers. You have to ensure that
>>each
>> antenna is matched properly. (I used LC matching
>> circuits.) Driving a 4SQ is more complex but should be
>> possible.
>>
>> George, AA7JV
>
> How did you determine it worked great? In most two
>element
> arrays the impedance of the rear element is virtually a
> short circuit
> Rick Karlquist
Rick,
The elements were 100 m long V beams that I used on 80 and
40 meters. Each element had its dedicated auto tuner (and
ballun). (This was when I was in AZ and had the space). I
had two SG-500 500 W amps. The elements were in an
end-fire configuration about 40 meters apart and the
tuners had no problem matching them. I used a remote
receiver with a small dipole to find the optimum phasing
angle. Also, on 40 the antenna worked much better than my
2 el Yagi!
73,
George, AA7JV
TKS,
George, AA7JV
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