GB867233A - Improvements in or relating to printed circuits incorporating high frequency coils - Google Patents

Abstract

867,233. Radio receiver arrangements. BRAYHEAD (ASCOT) Ltd. Nov. 7, 1958 [Nov. 7, 1957(2); April 11, 1958], Nos. 34751/57, 34752/57 and 11577/58. Class 40(5) [Also in Group XXXV] Tuning coils for television and other h.f. radio apparatus are formed by printing helical conducting tracks 8 (Fig. 2) on insulating wafer members 3, one or more of the coils being associated with a rotary wiper arm 14 by which its inductance can be preset to the desired value. The arm 14 may be slotted at 12 to allow radial adjustment. The arm 14 may be pivotally secured to wafer 9 by a screw or by an eyelet and may be soldered to the eyelet or to the coil when in the desired adjusted position. In a modification (Fig. 4) two inductively coupled coils are printed in appropriately overlapping relationship on opposite sides of wafer member 3. Tuning is effected by pivoted metal strips 41a, 42a mounted on the opposite sides of member 3 by bolts passing through slots in the strips to allow sliding as well as angular adjustment. Other coils 9 (Fig. 2) of cylindrical form and with adjustable cores 10 may be mounted on the wafers 3. The components on each wafer are connected to printed or other contact members 5a on the wafer edge and the wafers are mounted between rotatable circular plate members 4 (Fig. 1) to form a turret tuner. Alternatively the wafers may be mounted side by side in a stack (Fig. 3, not shown).