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Old May 31st 08, 11:56 PM posted to rec.radio.amateur.antenna
[email protected] nm5k@wt.net is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 757
Default Ladder line Vs. Coax

On May 30, 6:46 pm, "Ed Cregger" wrote:


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In all likelihood, no one on the other end will ever be able to tell the
difference after you make the changes. Neither will you.

Ed, NM2K


Maybe not from any practical standpoint, but I could see the
difference on a meter when I fed both a coax dipole, and a
ladder line dipole using the same tuner, which has antenna
switch, and meter built in.
So I could A/B real fast. I could see a slight difference on
receive switching between the two. And if it's enough to see
on a meter, I consider it a noticeable amount.
Most of the signals were in the 20-40 over 9 range being 75m,
and I'd see about 5 db worth of difference between the two
antenna/feed lines.
Course, I make no claim as to the exact DB amount of difference,
but I could see it on a meter.
After many years of 75 and 40 m operating using mostly NVIS
paths, I've come to the conclusion nothing will beat a dipole/loop/
turnstile fed with good coax for sheer system efficiency unless
say you had a run of several hundred feet or something...
Which of those three doesn't really matter much, although I
prefer the turnstile over the other two if I had a choice.
Nothing wrong with a loop, but in my cases, some sections
end up sagging closer to the ground, and you are often a
bit more prone to ground losses, and also overall performance
if sections of heavy current are low to the ground.
With a dipole or turnstile, max current is at the feed point, so
the ends of the wires height above the ground is often not quite
as critical.
As far as I can think of, only Cecil's no tuner/no choke system
would let a ladder line fed dipole equal or slightly beat a coax
fed. And in that case, I'm not sure how noticeable it would be,
being as the 213 I use is quite low loss at 3-4 mhz.
But like you say, for on the air, many would probably not
notice much. #1, you would have to do quick A/B transmit
tests for them to notice any difference, and also make sure
fading doesn't skew the results. It would be best to test with a
stable ground or space wave signal.
But... I still prefer coax.. I want every drop out I can get, and
I also much prefer the convenience of coax. IE: with most
antennas, no tuner required. And really not even a "balun"
required if you roll a choke out of the feed line itself and tie
wrap it. Weather is no issue with coax. I can have it sitting
in standing water with no problems.
The only time I use ladder line is mostly experimental
antennas where the feed point impedance is not the usual
50 ohms. If the mismatch to coax is high, ladder and the
tuner makes sense.