ABSTRACT. The apparatus now in use for radio reception, except the most simple types, uses election tubes. Electron tubes are used for reception in many different kinds of circuits. One of the most elementary uses is as a simple detector. It is also possible to use electron tubes in reception in circuits using various kinds of amplification, or regeneration, beat reception, or other methods. A simple electron-tube detector set will not serve to receive signals transmitted by continuous-wave radio telegraphy. This circular describes a simple electron-tube detector unit and gives a method of operating it. The set with electron-tube detector is more sensitive than a set employing a crystal detector and may be expected to give more satisfactory results. An antenna, lightning switch, ground connection, and telephone receivers which can be used in this set have been described in Circular No. 120. Tuning devices for use with this electron-tube detector set may be the tuning coil described in Bureau of Standards Circular No. 120 or the two-circuit coupler and variable air condenser described in Bureau of Standards Circular No. 12 1. For an electron-tube detector unit it is necessary to have an electron tube, socket for the tube, filament rheostat, grid leak, grid condenser, by-pass condenser, binding posts, and other minor accessories. It is also necessary to have a 6-volt storage battery and a "B" dry battery of 12 % to 4$ volts. Most of these parts should be purchased, although some can be made at home if desired. The cost of the complete electron-tube detector unit, including the tube and batteries, may be expected to be from $23 to $37. The principal part of this expense is the 6- volt storage battery. This estimate is exclusive of the cost of tuning device and telephone receivers described in Circulars Nos. 120 and 121, which may be from about $10 to $20. No estimate is made of the cost of equipment for charging storage batteries. The election tube, socket, condensers, filament rheostat, grid leak, and other parts of the detector unit are mounted on a wooden base and panel. The wood for the base and panel should be thoroughly dry and should preferably be protected by a coat of good electrical insulating varnish. A complete description of the method of assembling and wiring the detector unit is given. Illustrations are given showing the arrangement of the various parts and the complete assembled detector unit. The method of operating the set is also given. CONTENTS. 1. Introduction 2. Essential parts of complete radio receiving station 3. Description of parts 4. Assembly and wiring 5. Directions for operating 6. Notes on soldering 7. Approximate cost of parts Digitized by Google.
S. W. Stratton, director
Running title: Electron-tube detector unit