Best way to feed an open wire feedline is with a matching unit that IS a
balun. Not a ferrite core balun. An air core balun. Otherwise known as a
link coupled tuner such as a Johnson Matchbox or similar to what
previous responders to your post have mentioned. This requires using
parallel open wire feedline all the way to the tuner, which is usually
in the shack.
You say you can get coax in to the shack but you cannot get open wire
feedline to the shack. It may require some more creative thinking to
figure out how to do it. If you find a way to do it, you'll be glad you
did. If you can find a route for the open wire line that only has one or
two short sections where the feedline must pass through or near walls or
metal objects. then you just need to devise a way to deal with those
areas. How about two inch PVC pipe used as a conduit for the feedlline,
just where you need it?
My open wire feedline goes through the wall using feedthrough
insulators. It was easy for me, because my house is made of 3/4 inch
tongue and groove redwood. Yes that is right, separating the indoors
from the outdoors is only 3/4 of an inch of wood. Even so the method I
used could be used with a thicker wall. The ceramic feedthrough
insulators I used were only intended to be used through a panel, perhaps
no thicker than 1/4 inch. I bought a section of 1/4-20 brass allthread
at Home Despot, and some brass nuts, washers and wing nuts. I drilled a
hole through the wall of the same diameter as the outside diameter of
the PVC pipe I used. I cut the pipe to the right length to go through
the wall, in my case 3/4 inch, but it would work for any thickness wall.
Put the pipe in the hole, mounted plastic electrical box blank plates,
with holes in them for the feedthrough insulators, on both the inside
and outside wall surfaces. And then ran the brass thread stock through
the insulator, plate, pipe, other plate, other end of insulator. Brass
flat washers, lock washers, hex nuts, more flat washers and wing nuts
are on each end of the thread stock.The feedthrough point is under the
eaves, so should not get too much rain. I used some RTV sealant between
the plate and the wall, just to be sure.The brass thread stock does not
touch the PVC pipe, or the wall, or the plastic plates. It only touches
the ceramic feed through insulators.
DE N6KB
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