Seasonal Variation in the Strength of Radiotelegraphic Signals

The strength of received signals from two stations was measured at the Bureau of Standards over a period of about two years. The transmitting wave length was 1,000 meters, spark frequency, 1,000, and sending antenna current about 10 amperes for each of the transmitters. Their distances were respectively 185 and 235 kilometers. The curves giving variation in intensity of received signals are shown and discussed.