A Thin-Route Beyond-the-Horizon VHF System in the Middle East

The application of thin-route technique in an economical integrated small-scale VHF system in the 156-174-Mc band is described. The system provides point-to-point multi-channel voice, teletype and mobile communications between the main office of the Trans-Arabian Pipe Line Company in Beirut, Lebanon, and pumping stations and mobile units along the route of the pipeline through Lebanon, Syria, Jordan and Saudi Arabia. In addition, supervisory control and telemetering of 5000-HP combustion gas turbine pumping installations over portions of the system; including a 120-mile long link, is described. The terminals of this link and others, 90 to .05 miles long, are well beyond the horizon. Dual frequency diversity is employed. Several 250-watt transmitters and dual diversity receivers are duplexed on large arrays mounted on 200-foot selfsupporting towers. Two remote unattended relay stations are employed. System parameters, over-all propagation reliability, and plans for expansion as well as the economic attractiveness of a thin-route design for use in remote areas, are discussed.