Roger (K8RI) wrote:
> On 12/3/2010 4:58 PM, email@example.com wrote:
>> Instead of bringing the ladderline directly down the side of the
>> tower, 'twist' it as you do, thereby changing the distributed
>> capacitance of the two wires to the tower and 'equalizing' any
>> capacitive problems.
>> 3 or 4 turns should suffice for 50'.
>> One foot sounds good to me, too.
> I'd probably use about 1 turn per yard/meter as it's good for common
> mode rejection and the extra turns wouldn't hurt (within reason)
> I have no technical basis for choosing the number of turns/twists other
> than it being convenient and a tiny fraction of a wavelength at the
> frequencies they are likely to be used or encounter.
spacing out a foot, the coupling is pretty low regardless of how many
However, another good reason for twists is that it tends to reduce the
wind induced vibrations. That is, you don't want your feedline to be
aeroelastically vibrated to death like the Tacoma Narrows Bridge.
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