Reg,

Thanks for the demolition work! HI. I guess I was less concerned with
losses than detuning of the antenna system by an inadvertent
reconfiguration of the feedline should it come close to metal or
itself. Not so much per usage/session at the rig, but in the case of
doing a large turn of the antenna or in a high breeze situation that
would necessitate re-tuning between QSOs or mid-QSO. Or, at the very
least not distract me with large variances of SWR whilst I'm
transmitting. Still haven't looked into the slip ring method, but it
seems to me a good stiff ladder line or twinlead shouldn't pose too
great a problem in a rotary situation.

73,

Casey, KS7J

Casey,

What kind of directional antenna do you have, that you need to feed it with
450 Ohm line?

Tam/WB2TT

"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

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

Think in terms of slip rings as a contacts between the ladder line and the feed
of the Yagi driven element.
Bob WA2EAW