[Elecraft] Antenna feedline Placement
Stuart Rohre
[email protected]
Wed Mar 17 19:33:00 2004
You can make foam spacers for holding ladder line away from other feeders
and wall of conduit. The plastic conduit will have the least effect.
A large diameter metal conduit, that fulfills the spacing suggestions on
ladder line, (using the foam spacers) can offer an increased lightning
advantage. It can function as a waveguide beyond cutoff filter if
adequately grounded outside. It may depending on its length of run, even
cut down on electric noise getting to the shack on the outside of the coax
shield. As far as the coax is concerned, it will not "see" the parallel
line, as its RF field is contained between the inside of its shield and the
center conductor.
For the diameter that a ham could typically do for the conduit, you would be
better off using plastic.
But the spacers are a great way to maintain constant effect of the
dielectric of the plastic upon the parallel line balance.
-Stuart
K5KVH