An angled concrete base of circa 71 square metres for a substantial building known as the ‘Double A.T.I.’, corrugated steel sheet-sided building that housed antenna tuning inductors (hence the ‘A.T.I.’) at the centre of the 1914 and 1924 extended antenna array. It was of a striking angled form allowing its antenna and counterpoise connections to face each end of the antenna arrays. A porch of some 2.25 square metres extended from the southeastern elevation. Internal drainage was provided in the form of a semicircular section channel running along the entire inner perimeter, draining at each corner where the house bent to face each antenna. The ATI house has three iron threaded bolts at each corner to which either steel or timber framework was attached. The building was internally dry-lined with brown asbestos sheet. The base is littered with ceramic, glass and early thermoplastic (probably gutta percha) inductor and capacitor fragments, largely undisturbed since being smashed during salvage in 1939. Small concrete bases for the antenna straining masts are located circa 3m from the western and eastern gables, with counterpoise straining masts at either side of the gables. 

Source: Rowlands, J., Marconi's Carnarvon Station 1912-1939: a journey into early commercial wireless in north Wales' Second Edition, 2023.

RCAHMW, 2023.