Dave and Dirk,
Loop/ antenna amplifier for small magnetic loop antennas ( for any small antenna ) does not serve as an impedance compensation network unless you use a non - Foster method of impedance compensation or parametric amplifier.
Ordinary loop amplifier compensates for low effeciency of antenna due to its low radiation resistance.
Dirk constructed a loop antenna and antenna amplifier. In order to ascertain the amplitude frequency response of combined antenna and amplifier Martin suggested to run S21 measurement using VNA.
If this test shows unsatisfactory response in frequency band of his interest, Dirk should use S11 parameter set of his designed antenna that can be utilized for a design and simulation of matching impedance network between his antenna and
NE562 antenna amplifier.
For example, Chavdar used a simplistic impedance matching network ( shown as a plot of combined S21 with filter in Martin's recent reply ).?
Raphael
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