This book is written in an effort to meet the need and great demand for a general textbook on radio covering the new and extensive developments in the art made during the war. It is therefore devoted very largely to the study of the characteristics and use of the three-electrode vacuum tube in radio telegraphy and radio telephony, since it is around this device that the present and future of the science seem to center. But to meet the requirements of a general textbook, the principles involved in the older radio apparatus are also treated with sufficient fulness to inform the student on all essential principles of wireless communication.
The authors have presumed their fitness to write such a book because of their peculiar contact during the war with the new developments accomplished in this country and abroad, though not all of these developments, nor indeed the most wonderful of them, are herein published because of the wishes of the military authorities to keep them secret.
In the detail development of the principles involved, for which credit is due the first-named author, the electron theory is made use of frequently as it often gives a clearer conception of what takes place under certain conditions. Mechanical analogies are avoided. Mathematics is resorted to only to indicate the application in the problems of design, or the relations, in concise form, existing among the various quantities of a radio circuit. The description of any specific apparatus is purposely avoided, with the object in mind of devoting the entire space of the book to the principles involved, though the general means of utilizing these principles in practical work are of course given. With the principles understood it is a simple matter to apply them to any specific radio set.
The authors will welcome and greatly appreciate having their attention directed to any errors of omission or commission which may occur in this first edition.