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Old April 14th 04, 04:52 PM
Andy Cowley
 
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Cecil Moore wrote:

Larry Gagnon wrote:

Hello to all. I intend to erect an 80 meter full size dipole and feed
it with homebrew open ladder line. Would anyone care to reply as to how
to construct ladder line easily and effectively? How does one determine
spacing to get X ohms impedance line?





1/4" / 6 mm PTFE rod. From Radiospares in the U.K.
but there must be suppliers in the States. Cut into
suitable lengths with a hobby knife - I used 125 mm
but not critical. Drill holes 5 mm from each end,
making sure they are parallel. Holes should be about
1/2 mm smaller than the wire you are going to use. I
used 19/0.2 silver plated copper with a PTFE jacket.

PTFE is fairly soft and easy to work with hand tools.
The stuff available here is white and surprisingly
very unobtrusive visually, certainly a lot better
than black windowed 450 ohm twin.

Slit from the holes to the ends of the rod with a
hobby knife. Ease open with finger and push the wire
in. I used an aluminium ruler to push with. It will
'click' into place. You can adjust the spacer positions
easily but the grip is enough, even with PTFE, to keep
the spacers in place. Space the rods 12" to 18".
This will also work FB with bare copper conductors.

Apart from its excellent electrical characteristics
the PTFE is very good at shedding rainwater, which
can be a problem if you use other plastics, especially
tubes.

You now have some very posh mil-spec ladder line. I
can easily make 30' an hour with hand tools.

vy 73

Andy, M1EBV