Long Range Reception with Combined Crystal Detector and Audion Amplifier

If an audion bulb is used as an ordinary receiver, across the "stopping" condenser in series with a galena detector, an amplification of signals of about ten times is attained. The audion bulb used, to be effective for this purpose, must have certain definite voltage-current characteristics, which are described. The circuit diagram is given. Working with an antenna of an approximate fundamental wave length of 1,200 meters, a number of observations on stations up to 8,000 km. away were made.