Abstract
This thesis presents some practical results of the typical electromagnetic field distributions surrounding a leaky feeder in a tunnel. Amplitude and phase variations parallel to the feeder are investigated in order to provide a greater understanding of the mechanism of leakage. The possibility of locating a distant transmitter is examined and the prospects seem encouraging. Directional diversity is also considered as a means of reducing the effect of signal drop-outs. Finally, a detailed examination of the field distribution within a small volume of the tunnel is given. Although this is, primarily, of academic interest it can be used as a guide for determining preferable antenna orientation for optimum performance.