Abstract: My invention relates to improved method and means for a portable concealed structure locating and surveying exciter apparatus, and more particularly, to a portable device which couples by indirect connection alternating current energy into a structure which is usually obscured in a covert medium. A high stability source of first oscillations is provided which is undisturbed by perturbations in the degree of coupling between the concealed structure and the exciter, together with an adjustment, which is operable by a user of average skill, for maximizing the induction field when the apparatus is in the immediate presence of a large conductive structure which can otherwise affect the resonant efficiency of the inducer, thereby permitting the most effective use of an associated electromagnetic field detector apparatus of high selectivity.

Abstract: My invention relates to improved method and means for a portable concealed structure locating and surveying apparatus, and more particularly, to a portable device which provides separate operating conditions to best initially locate, then subsequently trace or survey a hidden structure or extended object with a minimum of operator interpretive skill. My invention includes an inductive exciter which couples by indirect connection alternating current energy into the structure which isusually obscured in a covert medium. My invention includes also a portable translator which is, in the locating or spotting mode of operation, operating with gain modulation at a slow periodic rate to enable the use of the full, noise limited, gain capablity of the electronic amplification means. I have further conceived a novel way that the noise thus resulting is used as an aid in the initial locating of the indeterminate structure lay.