High q tunable if transformer coil assembly

Claim 1

A high Q tunable IF transformer coil assembly comprising a base of insulating material, a core of magnetizable but unmagnetized material fixed on said base end arranged along a first axis, a coil fixed on said core and wound about said first axis, said coil being so dimensioned and formed of such wire as to be usable as an inductance of frequencies in the MegaHertz range, and a magnetic member mounted on an adjustably positionable relative to said base, said magnetic member being located in the magnetic field of said coil and movable with respect to said core so as to translate along a second axis, thereby to vary the inductance of said coil, said second axis being substantially perpendicular to said first axis, thereby to increase the effective Q of said coil, sAid magnetic member comprising a substantially cylindrical structure located radially outside said core and telescopically movable relative thereto translatably along said second axis, the radial space between said cylindrical structure and said core being substantially of uniform width in all operative positions of said cylindrical structure and being free of electrically conductive material, said assembly including structure which, together with said base, substantially completely encloses said coil and core, said coil having leads extending out through said structure to the exterior of said assembly.