In regard to the advantages of open wire line I have these comments. I keep
reading all these techniques on TT on how to seal coax joints with tape and
fancy sealers from wind blown rain. You don't need any of all these band
aids when using open wire line. I used Silicone grease on soldering lug
connections with SS bolts--right in the rain. I had a quad loop and the open
wire line of the same diameter loaded up with ice a couple of times. I
connected a 304TL filament tranformer on a variac and melted it off. The
cylinders of ice feel off with a slot in them. Try that wih coax.
If open wire line is damaged by falling trees you only need a soldering iron
for a repair---not your check book. It will last your life time.
Unfortunately most comments of open wire line and suggested use such as the
proper lengths come from those who have never used it and QST.
Big coax cost money and the connector prices are high. I plan to make some
big coax for long runs at VHF&UHF with 2" PVC and about .4" center covered
with long strips of aluminum foil using contact cement to attach it. You can
get a range of Zo's just by changing the diameter of the center conductor. I
will try a copper foil version also. Elbos and joints are available. It
will have thin disks with holes for spacers for the center rod. I'll have
drain holes for condensation. This is the
"K7GCO Retiree Metamucil" version of inexpensive coax that's easy to repair
of necessary.
I can see it now. A 2-300' long balanced PVC 2" coaxial feedline (for QRP)
feeding a HF beam or a VHF/UHF antenna like moon bounce and converted to
unbalanced by you guessed it--a VHF/UHF version of the Johnson Match Box. I
already have one on 6&2M. They work great. My 6M MB with a 200 ohm balanced
link input, matches 100 ohm balanced coax from a 2 element quad. It was the
only 6M antenna I tried that didn't have TVI. No baluns or impedance
matching (1:1 SWR) at the antenna were needed either. k7gco
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