TROPOSPHERIC SCATTER - AUTOMATIC POWER LEVEL CONTROL.

This article highlights the problems associated with enhanced propagation caused by ducting conditions often encountered on tropospheric scatter links. The limits imposed by such conditions on reciever performance and on the acceptability of tropospheric systems as a whole are explored and measures to reduce these limitations are discussed. The operating parameters required for their implementation in the form of an automatic control system are outlined. This new control system utilizes a closed loop over the link and is automatic in operation. The transmitted power is controlled in accordance with signal level measurements performed at the receiver, the control information being relayed over the link via normal supervisory channels. The hardware being developed to control the transmitted power is described.