[Antennas] Why not twin lead?

[Pat W]

 It would be nice to be able to use twinlead, or
ladderline for Vhf.  THe problem is that when the Z0 of
the feedline does not match the Zin at the transceiver,
the Zload at the antenna gets transformed to something
other than 50 ohms.  Using 1/2 wavelength of line
should solve this but how to you know what is an exact
multiple of 1/2 wavelength ?  If you're off by a few
inches that could really mess up your SWR.
 An alternative would be to have transformers at each
end of the twinlead to step up/step down the load
impedance, but, I haven't seen anything published on
what materials to use at VHF.  I can build really nice
broadband(160m-10m) 4:1 or 9:1 transformers for HF but
VHF is a totally different animal.

 Pat W0OPW

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