Range of multichannel radio links between 30 and 10000 megacycles

Discusses the factors chiefly concerned in the recent advance of microwaves from line-of-sight links only to over-the-horizon ranges. The subjects dealt with include the permissable limits of receiver noise, the received field-strength and the effect of expandors. Also discussed are the aerial gain, the width of the beam and the type of radiator, such as a paraboloidal reflector or dipolearray, and its dependence on frequency. The maximum power available from modern valves is considered. The attenuation over a 50 km free-space path is plotted against frequency, together with a second curve showing the allowable margin for fading to provide 99% reliable operation. Further curves show the attenuation as a function of distance for certain frequencies, together with a correction curve giving the additional attenuation for beyond-the-horizon propagation. The final curve shows distance plotted against frequency for a receiver input of -70dB referred to 1 mW using the preceding attenuation figures and maximum radiated power.