[HBR] Looking for that three section variable

[Ian Wilson]

I can't imagine why adding a high-quality series capacitor would
introduce instability. I would add the cap at the 'live' end, though - you
the multi-gang variable capacitor will probably have all sections sharing
a common rotor, which wants to be grounded.

The drawback of adding series capacitance is that the rotation versus
frequency law will change. If you reduce capacitance by a lot, the
tuning scale can become very nonlinear and cramped at one end.

73, ian K3IMW