Reference-crystal-controlled v.h.f. equipment

A brief allusion is made to the value and usage of v.h.f. equipment capable of crystal-controlled operation on a large number of channels, any one of which may be selected by the setting of one or more dials to the cipher or letter combination characterizing this channel. A survey is made of the methods of obtaining this facility from a small number of crystals built into the apparatus, one of which controls a harmonic generator whose frequency is related to the channel spacing. The authors have ventured to coin a generic term for equipment of the above somewhat cumbersome description, namely ¿asac¿, as representing ¿automatic selection of any channel.¿ The methods conceived by the authors are placed in relation to the field surveyed, and are elaborated with particular reference to the TR.1407 and some similar equipments.