It would seem that inductor and capacitor need to be individually controlled as the values would be extremely different as the operating freq will change. The capacitance and inductance will not track each other.
Fred
Fred,
Think about it more...
Each turn of the inductor is like moving the tap along the length of the inductor.
For each tap we can assume that the cap is a full mesh.
So L = 1 to N (where N is turns)
while for each L, C = max ufd (when the cap is fully meshed).
...same as a variable L, with a fixed C.
Now as we rotate the L between N, and N +1, the cap will go from fully meshed to unmeshed in 1/2 turn.
So for each value of L you can "rock" the cap back and forth to get all values of ufd between "0" and "C" (max ufd)!
The only down side is that for fully 1/2 of a rotation of L there will be 1/2 turn where the values of C repeat in reverse order (as you go toward full mesh, and then away from full mesh). (but the values of L will be slightly different... maybe a plus?)
So, it seems workable, but the thing will dip and peak if you are rolling through the range... seems best to tune at low power for the sake of the transmitter's finals... although maybe you could tune for best match using an antenna analyzer or noise bridge?? And maybe you need a "fast/slow" feature too...
_-_-bear