Topband: Ladderline

[KN4LF, Thomas Giella]

K2WH:
>  I do not recall ever seeing any antenna projects or designs utilizing open
>wire or ladder line to feed a 1/4 wave vertical.

  I use 450 ohm ladder line as a feedline with my 160 1/2 wave T. One side
of the ladderline goes to the radial system, the other to the T. I use a
homebrew balanced matching network (two roller inductors in series and a
split cap across to ground) in the shack and I seem to get very little
harmful radiation from the feedline, which is mounted 5 feet above ground. I
guess ladderline is unpopular on a vertical because of the potential
feedline radiation problem. My ladderline twists as it goes to keep
impedance in symmetry. The T loads up and works like gangbusters on 80-10
meters.

  With a coaxial line you can place the ferrite beads on it at the
feedpoint, to choke off feedline radiation, therefore it's a more popular
alternative.

73,
Thomas Giella, KN4LF



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