On Oct 5, 12:50*pm, Jim Lux wrote:
Tom Horne wrote:
Hi

I'm anticipating converting my coax fed, ninety foot long, folded
terminated dipole to a ladder line fed folded dipole, without a
terminating resister, fed using an Icom AH-4 antenna coupler. *Am I
correct in believing that the best ladder line to use for that purpose
would be the 300 Ohm type to match the nominal impedance of the folded
dipole itself.

Is this a multiband application?
If you want to keep all the wires, I'd make it a fat dipole (rather than
folded).
Why not put the AH4 at the feedpoint and feed with Coax? *The box *is* a
bit heavy, but it is weatherproof, and you could run the power/control
wires alongside your coax.

As to why not put the coupler at the feed point I would point out that
the statement "The box *is* a
bit heavy," would pass as a masters dissertation in understatement. An entire center support would have to be created or I would have to rig a catenary at the present support points and lower the antenna closer to the ground to permit the catenary to take the weight of the antenna coupler. I would point out that this present Folded Terminated Dipole is not Tilted but instead is rigged as a flat top. Height is might; so the old radio axiom goes; so I would rather not have to lower the antenna just to avoid using ladder line. Additionally in order to compensate for the bending of the trees that support the antenna now I would have to rig a second counterweight and puller system to keep the antenna itself from being torn apart since the first one would be in use to keep a constant tension on the catenary. That is a lot of work in order to avoid the use of some ladder line that probably has a lower loss than the additional coax that would replace it.

--
Tom Horne, W3TDH