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Old April 16th 04, 12:21 PM
KC1DI
 
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On Fri, 16 Apr 2004 04:15:57 GMT, zeno wrote:

I have a spool of 300 ohm antenna feed line out in the barn,
never been used. Probably enough there for some kind of
antenna, I will have to unspool it and see how much is there.
Anyone have anything good to say about those folded dipoles
that use this 300 ohm line for both the antenna and the feed
line? I have seen illustrations of folded dipoles using
this, but in actual practice this line will naturally have
some twising when it is suspended. I cannot imagine how you
would keep it from doing this to some extent. What effect
would this twisting have on the effectiveness of the antenna.
The illustrations always show them geometrically perfect and
straight and parallel.


Bill


Hi Bill,

Used just such an antenna a long time ago, Worked great.. and was
cheap to make.. Problems that take some engineering

300 ohm line is not strong thus it will break either due to wind
action or smiply from weight of snow or ice if not well supported. .

you'll need a good method of supporting the connections at the center.

when wet resonant frequency will change.. lower if I remeber
correctly.

you'll most likely need a tuner -- or an old tube rig like we used
that wasn't that fussy about SWR.

Power limited to about 200watts.. safely. Less if not tuned exactly
or if line is wet.

there is not much advantage over an ordinary dipole.. it is for the
most part a single band antenna. But can be used like a dipole on 3rd
harmonic.

My recomendation put up a regular dipole , feed it with the 300 ohm
stuff and a good balanced tuner.. you'll get more milage that way.

73 Dave Kc1di



 
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