Machen repeater station

The low power VHF sets used by the Special Duties outstations, known as TRD sets, were capable of transmitting 30 miles, and in good atmospheric conditions, 60 miles, but could only transmit on line of sight. The topography of the South Wales valleys therefore required concealed repeater stations. There is no known record of their location, but we can infer their locations based on path analysis, backed up by historic aerial photography.

Sergeant Jack Millie who helped build the network said, “The nature of hilly Wales proved a huge headache for our small power VHF static network”

Captain Ken Ward who helped set up the Special Duties Network reported that, “In some areas we had to establish concealed repeater stations between coast stations and the “met” hut.” 

Mynydd Machen sits above the Caerphilly basin, blocking direct transmission between the Rudry Suboutstation and the Blorenge Instation. A 1947 aerial photograph show a single, isolated, pole supporting three or four horizontal aerial bars. This may be the site of a repeater station or another unrelated structure. Further information on this site would be welcome.