> It's not your antenna wire.
>
> You don't have the right kind of balun(s).
That was my thought also Jerry. He has a grossly off center
fed antenna. That means the common mode excitation of the
feedline would be horrible.
He'd have to use a coupling device with extermely high
common mode isolation. Since he said it is a 4:1 single core
balun we know for sure it is a voltage balun, and a voltage
balun has almost no common mode isolation. Any single core
balun with a ratio other than 1:1 , unless it is an isolated
primary-secondary type of transformer, cannot be a current
balun. It always would try to force output voltages in a
certain ratio.
(Interesting that Sevik seems to think transmission line
baluns do not excite the core. At least that's what the web
page he posted says. Don't know where that idea comes
from!!)
> Because of the off center feed, your antenna right now
consists of about
> 196 feet on one side, and on the other side, two connected
wires. One
> is about 38 feet of antenna wire and the other is your
coax (ever how
> long that is). The coax shield is acting as the other half
of your
> antenna. You would be extremely lucky if it was resonant
on 160 meters.
Even a balanced line would act like part of the antenna if
there was no common mode isolation. Antennas like this model
well unless you do the model correctly and include the
transmission line. If you do not add conductors representing
the transmission the model assumes perfect common mode
isolation. In other words the models assumes a perfect
current balun with infinite common mode isolation. Then what
he actually did was connect the worse possible type of balun
in one test.....and no balun at all in the other test. With
the antenna in the real world things are grossly different.
Now the source is coupled through a long conductor pair
feeding the antenna, and common mode currents make the
feeder a significant part of the radiating structure.
The greater the feedline offset from center the higher the
common mode isolation has to be in the feed system. Worse
possible case is an end-fed halfwave antenna. He is almost
there with the offset he has in the feedline!
I can't imagine why anyone would ever want to use a balun
that forces a specific terminal to feedline voltage ratio.
That's the absolute worse balun for any antenna. Other than
an isolation transformer system it is electrically
impossible to build a balun other than 1:1 on a single core
or single stack of cores. So if you see you have one core
or one stack of cores with a wining around it in a balun
that is not 1:1 ratio, you know you have an inferior balun.
73 Tom
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