The Measurement of Radiotelegraphic Signals with the Oscillating Audion

After considering procedure and accuracy in the measurement of audibility by the shunted telephone method, the author gives an arrangement for calibrating a usual audibility box when it is employed in conjunction with an oscillating audion. The method is found to be accurate to better than 20 per cent., exactly as with other detectors. The absolute sensitiveness of the oscillating audion is found to be 1.2(10)<R>-15</R> watts for a just audible signal. This is more than (10)<R>6</R> times the watt sensitiveness of the electrolytic detector and 6(10)<R>5</R> times that of the normal audion on buzzer signals. The details of the measurements and the necessary precautions are described in detail.