On Fri, 2007-12-07 at 13:35 -0500, John Huffman wrote:
> Bob -
> Bob (VUF), I agree with what Bob (TAX) says.
> My dipole is fed with 100' of modified Ladder line. I got tired of
> re-tuning when it rained so I cut 2/3 of the webs out of the ladder
> line. Works great for me.
> I have tried the MFJ Balanced tuner, auto-tuners, baluns, no balun, and
> the Ten Tec 229. What I kept was a balun outside my window (DX
> Engineering 2:1) and 6 feet of RG8 from the balun to the tuner. I kept
> the Ten Tec 229. T-matches seem to have lots more loss. A nice L-match
> works fine here. The Ten Tec 229 (238, 238B, etc.) has a place on the
> back to add capacitance for 160 meters.
> So, ladder line to balun to tuner. About the same as half the ham
> There are lots of opinions on how to get from the ladder line to the
> radio. I have tried them all and can't see a difference. YMMV :-)
> 73 de K1ESE
Open wire line on a general coverage dipole has the advantage over coax
that the line impedance is in the middle of the range of impedances the
antenna will show, keeping the SWR down and in a range that makes for
fairly easy tuning. By that I mean the antenna Z will be 40 or 50 ohms
minimum (unless at 1/4 wave end to end) and 1000 maximum and so a 300,
450, or 600 ohm line is somewhere in the middle. And that line tends to
transform the wide swings at the antenna to somewhat smaller swings at
the tuner in the shack.
73, Jerry, K0CQ
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