For all AAE’s valuable studies of Macquarie Island’s landforms, weather and biology, the wireless relay was the reason the party was there in the first place. Intercontinental radio-telegraphy was in its infancy, and the range of Mawson’s equipment required a two-stage transmission from Antarctica to Hobart. For this, Macquarie Island — about half-way between Tasmania and Antarctica and slightly to the east — was ideally situated.

Arthur Sawyer operated the wireless plant, in collaboration with engineer Charles Sandell, who was responsible for the wireless’s power generator. At the outset the two were flying blind, not knowing whether they would be able to receive morse code messages from Mawson’s party at Cape Denison (or anywhere else), nor whether any of their transmissions would be received. All they could do was transmit, wait and hope.

By the end of January 1912 the wireless equipment was operational. The initial arrangement was that Sandell and Sawyer, along with the party’s leader, George Ainsworth, took turns sleeping in the wireless operating hut at the top of Wireless Hill. Sandell’s engine house was built some distance away so that the sound of the power generating plant would not interfere with Sawyer’s attempts to hear incoming signals.