[CQ-Contest] Feedline length

[Tom Rauch]

> Hi guys, I've heard several times that the length of a feedline must
> be = cut to 1/2 wavelength or multiple (1, 1.5, 2, ...). Someone else
> say it's better odd multiples of a 1/4 wavelength (1/4, = 3/4, 5/4,
> ...) to minimize interaction between feedlines running the = same
> path, for example when feeding monoband beams. Is there any particular
> reason to do in a way or another

If a feedline is matched, it has the same impedance along the 
entire length...assuming reasonable loss.

If it is not matched, the impedance will vary with length but not the 
SWR...assuming minimal loss.

Coupling between antennas can absolutely NOT be defined by 
anything like line electrical length. Coupling between lines is a 
mostly a function of lack of proper feed methods or use of baluns 
when required.

Make the lines whatever length you need to reach the rig, unless 
you have a real reason to make them a special length (like you 
intentionally have SWR, or are phasing antennas).  
73, Tom W8JI
W8JI at contesting.com 


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