GB506133A - Improvements in or relating to the reception of radio transmissions - Google Patents

Abstract

506,133. Wireless receiving-apparatus. MONGE, G. DE. Sept. 1, 1938, No. 25647. [Class 40 (v)] [Also in Group XXXVIII] Apparatus for indicating on which wavelengths of a given frequency range transmissions are taking place, comprises a radio receiver which operates a plurality of indicators through switch mechanism continuously rotated with the tuning element of the receiver. The tuning condenser 4 is mounted on a shaft 3 which is continuously rotated by a driving motor 1. A waveband switch 6 and multicontact rotary switch 7, 43 are also mounted on the shaft 3, the switch 6 acting to shortcircuit part of the tuned circuit inductance 8 during each alternate half-revolution of condenser 4 so that ail extended frequency range is covered. The incoming signals impressed on the circuit 4, 8 are amplified at 13, rectified and fed to the grid of valve 19, appearing in the anode circuit as voltage pulses corresponding to each station received in the band covered. These pulses are fed to condensers 38 .. 42 by means of rotating arm 7 successively engaging contacts 25 .. 29 which are individually connected to separate grids 30 .. 34 of a discharge tube indicator 35 having a cathode 36 and anode 37 on which fluorescent indications appear on excitation of a grid. These indications are associated with a wavelength scale 46 which is movable by knob 45 and linkwork 47 together with the disc 43 to make a slight adjustment for the case in which a received transmission falls in between two of the contacts 25 ... 29.