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LC circuit in MOSFET drain

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I14R10

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On this schematics http://d16837591.u227.surftown.dk/oz2cpu/20m/new-amp.htm

R1 and R2 are not used, as the author says. Why? If there was 2.2k resistor parallel to LC circuit in drain, then in resonance imepdance of that RLC circuit would be 2.2k and then the transformer in drain would make sense. 2.2k impedance would be transformed into 50 ohm.

But if there is not 2.2k resistor, then in resonance LC circuit impedance would become infinite (theoretically) and the transformer would not transform the impedance to 50 ohms. It would be much higher. Is there a reason for this?
 

The impedance of a real LC circuit will never become infinite, just Q*|X|, could be 5 or 10k in this case. Also the finite MOSFET output resistance is loading the LC circuit.

A possible purpose of the parallel resistor might be to increase the circuit bandwidth, at the same time it reduces the gain. I presume, there's no urgent need to do a 50 ohm matching for the amplifier output.
 
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    I14R10

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The impedance of a LC circuit at resonance is L/Cr where r is the series loss resistance of the coil, this is in parallel with the drain resistance of the FET. R1 and R2 are to increase the bandwidth.
Frank
 
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