I've been thinking of getting some roller inductors to play with next time I
visit a hamfest, and it occurred to me that a generic roller inductor
doesn't have a linear change in inductance with roller position... does it?
E.g., at the half-way point you should get 1/4 the total inductance, right?

Or is the form wound such that the turns are closer together at one end than
nothing, thereby linearizing the inductace vs. roller position to some
degree?

Thanks,
---Joel Kolstad

P.S. -- They never made small (say, size of an old Kodak film
canister)-sized roller inductors meant for QRP work, did they? Most seem to
be sized for hundreds if not thousands of watts.