dave arruzza wrote:
> To all,
> I am installing a elevated 40 meter 4 square over somewhat marshy New England
> soil.
>
> My property backs up to a drained 30 acre pond. You can see my QTH on Google
> Earth. It's the house before the property with the greenhouses.
>
> Base elevation is 20' above ground utilizing 2 - Rohn 25 tower sections per
> element. Elevated ground plane.
>
> I wish to use 3/4 wave phasing lines instead of 1/4 wave phasing lines so I
> can dress the phasing cables down the tower legs and underground to the
> Comtek box.
>
> The Comtek manual states to use only 1/4 or 3/4 wave cables and I understand
> that.
>
> Has anyone observed any determent in using the 3/4 wave cables vs. 1/4 wave
> cables?
>
The real difference is that the phasing will be more narrow band (for a
given phasing error). That is, say you cut your cables for 7.1 MHz. At
7 MHz, a quarter wave will be 88.7 degrees, the 3/4 will be 266 degrees.
The first, an error of 1.3 degrees, the second, 4 degrees.
Neither is particularly huge. 4 degrees will turn a perfect null into a
-26dB null.. hardly a crisis.
You'll have bigger phasing errors from differences in the ground under
the antennas and other component tolerances.
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