Urban congestion and solar cycle effects on CB radio range

The proliferation of Citizen´s Band radio has occurred during a period of low solar activity when sky-wave propagation of 27 MHz signals was unlikely. Lucas (New York Times, July 11, 1976) pointed out that ionospherically propagated interference might significantly decrease the local range of CB radios near the peak of a solar cycle. On the other hand, increasing local congestion has already decreased this range in urban areas. The combined effects of noise, local co-channel interference, and sky-wave interference on radio range have been computed as functions of solar activity, fraction of the population transmitting on a channel, and area population for reasonable statistical distributions of transmitter and receiver characteristics. The model and the input data used in the calculation will be described.