On 3/28/2016 9:14 AM, Jim Brown wrote:
On Mon,3/28/2016 4:37 AM, KE1F Lou wrote:
Is the lowest SWR is the resonant frequency?
Resonant frequency is when Xl=Xc.
When Xl=Xc is not necessarily the lowest SWR.
Exactly right. If, for example, the antenna's feedpoint impedance at
resonance is different from the feedline impedance, or if the analyzer
impedance does not match the feedline impedance, the lowest MEASURED SWR
73, Jim K9YC
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I don't believe the above assertion.
Can anyone give a specific example of an antenna having
an SWR at the resonant frequency, (where X=0), that is higher than
the SWR at frequencies slightly above or below the resonant frequency?
I submit that a local minimum in the SWR will always coincide
with X=0. This is easily proved on a Smith chart, where X=0
corresponds to the X-axis. Adding reactance or susceptance moves
the impedance farther from the origin in all cases, meaning
SWR goes up.
Rick N6RK
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