[Elecraft] : Resonance

[David Woolley (E.L)]

Don Wilhelm wrote:

> dipole.  The fact is that a wire of any length can be made to take power 
> at any frequency by feeding it with the conjugate of its feed impedance 

Although I agree with most of the preceding, the above statement hints 
at a common misunderstanding.  In general, you do not want to feed an 
antenna from a source impedance that is the the complex conjugate of its 
impedance.  Doing so guarantees that you cannot exceed 50% efficiency.

Whilst such matching will give you the highest power for any given open 
circuit voltage, it will not give you the highest output power for a 
given input power.

When one says is a transmitter is matched to 50 ohms, one actually means 
that its output network presents the optimum load to the finals when 
feeding a 50 ohm load.

-- 
David Woolley
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