Gilmer, Mike wrote:
>> if the impedance of the antenna is different from the impedance of the
>
>> feedline.
>
>This is EXACTLY the case I'm talking about. I said the antenna's
>impedance was transformed by the cable. This means the Zcable does NOT
>equal Zantenna. In this case, you said I could get a 50-ohm point at
>some cable length. If I have this cable length, and I treat this
>cable/antenna as a black box (which is what I tried to describe above)
>what does my SWR meter between the amp and the blackbox read?
No, if your antenna impedance does not equal the impedance of your
transmission line (ie: 50 Ohms for coax), you will never have a length of
coax where your impedance equals 50 Ohms with no reactive component. The
50+j0 point on a Smith Chart is the very center of the chart. A VSWR has
the 50 Ohm point as its center. Therefore, since moving along a
transmission line moves you along that constant VSWR circle, no length of
line will put you into the 50 Ohm point! You'll just rotate around the
chart repeating every so often the same impedances.
The only way to get to the 50 Ohm point is to add some reactance in shunt
and/or series configurations to the transmission line.
73,
Jon
KE9NA
--------------------------------------------------------------------------
The Second Amendment is NOT about duck hunting!
Jon Ogden
jono@enteract.com
www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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