Topband: Open wire feeder

[Richard Karlquist]

> limited applications.  However, I have a 160 transmit antenna that I'm
> constructing that will be about 800 cable feet from the shack.
> I'm considering using 450 ohm open feeder (the PVC coated variety).  Any
> W0FLS

I have 850 feet of open wire line to my 160 vertical.  There
are numerous photos of it on my web site at
http://www.n6rk.com/openwire.html.
It is 4 AWG stranded aluminum XHHW wire, spaced 5 inches.  At
both ends there are baluns to convert from unbalanced 50 ohms
to balanced 50 ohms, and transformers to convert from balanced
50 ohms to balanced 450 ohms.  The loss including the transformers
is measured in tenths of a dB.  The supports are just PVC pipes slipped
over T posts at 50 foot intervals.  Additional line spacers
go between wires in between support posts.  I put about 100 lbs
of tension on the wires.  I have been extremely happy with
this system for several years now.

If by "450 ohm open feed (the PVC variety)" you actually mean
ladder line, I wouldn't advise that.

BTW, I operate my line matched.  As was pointed out, if you
operate it at high VSWR, you have to retune every time you
QSY.

Rick N6RK