Ruinous stone foundations and remnant brick walls of a late 1914 military guarding blockhouse for the then single Marconi antenna, identified on a contemporary site map as blockhouse number 4 (of ten surrounding the site). It measures 6m long by 5m wide. Clear remains of firing ring holes are seen in places, as in most other blockhouse remains around the site. The structure is located immediately adjacent to, and offset from, a stone-built incline running from the transmitter buildings at the western end of the site, for the transport of materials to build the antenna arrays from 1914 onwards.

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

RCAHMW, 2023.