New Zealand established a weather and radio station (callsign ZME) at Raoul Island (formerly Sunday Island) in the Kermadecs in 1939.
Weather observations were transmitted from Raoul Island to New Zealand by radio every three hours, for use in weather forecasting.
There were two lattice towers: one to the west and slightly north of the radio station and its fellow to the east and also slightly north of the radio station. This was solely for the 500kHz antenna, which was a version of the Marconi T. I believe that Jack Clinch was the original radio operator at ZME and I can recall talking with him about his experience. He did mention that 500kHz was the emergency frequency for small island stations and it fitted in also to the coastwatch duties of that time. While I was at ZME it was our emergency frequency and we tested its reliability by calling Auckland Radio ZLD once a month. Other than regular schedules there was no regular monitoring of Raoul Island HF transmissions.
About 100 metres farther along the path there was a west-to-east line of three wooden masts and about 25 meters farther a two-mast line along roughly the same bearing. I think we had a 2-14MHz Rhombic antenna plus a couple of dipoles cut to our normal HF schedule frequencies. It was all Morse; there was no radiotelephone at all.
– Clyde Williams