View Single Post
  #10   Report Post  
Old November 4th 03, 04:31 PM
Tarmo Tammaru
 
Posts: n/a
Default

You might want to check on a Smith chart to see how bad things get if you
patched in about 3 - 4 feet of coax. I know this has been done before. You
could also make up a short piece of 100 Ohm balanced line from 2 pieces of
RG8, and put 4:1 baluns on each end of that.

Tam/WB2TT
"KS7J" wrote in message
om...
"Tarmo Tammaru" wrote in message

...
Casey,

What kind of directional antenna do you have, that you need to feed it

with
450 Ohm line?

Tam/WB2TT


Well, I don't *need* to feed it with ladder line, I *want* to feed it
with it so that I can use it multi-band. It is armchair fantasy at the
moment, no antenna yet exists, but it would be essentially a 40/30 2
el. yagi (it's a bit more complicated than that, but I'm still
designing). My very preliminary modeling indicates that at resonance
you get the typical yagi directional pattern. Driving it on other
bands, even with high SWR, will yield anything from normal dipole to
meaningful gain in one direction depending on band. So, at the least I
could have a rotatable dipole on the non-resonant bands and a bit of
F/B on one or two with some luck.

73,

Casey