Quantity of parts from 4GHz Manchester - Kirk O' Shotts television microwave link, 1952

Quantity of parts from 4GHz Manchester - Kirk O' Shotts television microwave link, 1952

The 4GHz Manchester - Kirk O' Shotts television microwave link provided by the Post Office in 1952 used to relay the BBC's television service to Scotland was the first commercial link in the world to operate in the 4-GHz band and the first to use a travelling-wave tube (TWT) as its power amplifier. Seven intermediate stations spaced at an average distance of about 30 miles were used, the total route length being about 400km (250 miles). The equipment was manufactured by Standard Telephones and Cables Ltd.

When opened in 1952, the 250-mile Manchester - Kirk O' Shotts microwave link was the longest link in the General Post Office's (GPO) permanent television network and was used for the inaugural regular BBC low-power television transmission.

The transmitter bay from one of the intermediate stations housed a travelling-wave tube (TWT a separate object part) and the local oscillator, whose output was mixed with the 60-MHz signal entering the bay, to provide the TWT with its 4-GHz input.