Apparatus for Detecting the Presence or Approach of Air Craft.

Abstract

Abstract 23,570. Graham, E. A. Oct. 15. Locating sounds; aeronautical signals. - In sound-locating apparatus particularly designed for detecting air-craft, comprising a trumpet or other soundcollector b associated with a microphone a connected to a telephone receiver d, variable resistances, inductances, and capacities, r, u, s and p, t, v, respectively, are connected in the circuit to minimize hissing and other local noises and to tune the apparatus to detect faint and distant sounds. According to the Provisional Specification, the microphone may be of the ' Blake ' or of the pencil type, or may be of the granular type provided with an agitating-device as described in Specification 17,086/06, [Class 40, Electric telegraphs &c.].

Inventors

• 👤 Edward Alfred Graham

Bibliographic Details