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Old January 5th 05, 04:47 PM
Bob Miller
 
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On Tue, 04 Jan 2005 06:35:12 -0500, Gary wrote:

I'm mulling over different antenna designs for this spring / summer
and a friend of mine has suggested for 80m on up a full size 80 meter
"dipole" 66' X inches per leg, center fed with 300 Ohm twinlead. He
has this arrangement and the twinlead comes into his house and is
connected to two 10' sections of RG-8X both rolled into a coil about
6" in diameter. He then takes and connects the braid and shield of one
of the coax coils to one leg of the twindlead and I'm not exactly
certain how the other leg is connected. He claims it's a 4:1 coaxial
balun. I wonder if some of the experts here are familiar with this
type of arrangement. He claims it has lower losses than connecting it
to the 4:1 balun in his tuner. Any thoughts on the subject ?

Thanks in advance

73 Gary K8IQ

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Gary, I have a kit #835 from the Wireman that is a 4-1 balun -- it
uses two pieces of paralleled coax with ferrite beads. That is the
closest I've heard to the twin coax deal you describe above. Don't
know that you really need such a balun -- a standard single coil of
coax, or a W2DU type with ferrite beads on a short length of coax, or
the 4-1 balun that comes with your tuner -- any of these should work
with your center-fed dipole. Right now, my 130 foot dipole with
ladderline works best with my tuner's built-in 4-1 balun.

I'd just put the antenna up, and then experiment with different ways
of feeding it to your tuner -- I imagine every installation will work
a little differently depending on how high your antenna is and how
long your ladderline is.

bob
k5qwg