Hi Mike,
Thanks for correcting my mistaken assumption. I was thinking that the imbalance can increase 2nd harmonic generation (IP2), which in turn also increases IP3 because the latter also depends on the 2nd harmonic, as in 2f1 - f2 and 2f2 - f1. Or is my logic flawed?
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I have also uploaded a graph comparing the CMRR of the three active loops.
/g/loopantennas/photo/300229/3878684
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Referring to the graph linked above, I hypothesize M0AYF & PA0FRI have significantly higher CMRR than?LZ1AQ because the former two incorporates a shared emitter resistor and emitter inductor, respectively. In the PA0FRI, CMRR is poor at the lowest frequencies due to the decreasing inductive reactance (XL), but as the frequency increases, the XL also increases, hence resulting in it having the highest CMRR at the upper HF range. Although M0AYF's emitter resistor is constant over frequency, the parasitic cap shunting the resistor causes its CMRR to degrade gradually with frequency.
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73, Leong, 9M2LCL (ex 9W2LC).
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