Some aspects of permeability tuning

In the first part of the paper, permeability tuned circuits are analysed and compared with capacitance tuned circuits. Attention is given mainly to aerial circuits for the broadcast band. The second part of the paper deals with the construction of permeability tuners. The causes of law and tracking errors are discussed and an indication is given of the manner in which these errors can be reduced and corrected. Finally, a tuner is described which features an adjustable tuning law, as well as approaching the ideal linear frequency law more closely than do most of the commercially used tuning capacitors.