United States Navy
| Mast radiator insulated against ground|
Lualualei, Hawaii, United States
BREN Tower, KVLY‑TV mast, Jim Creek Naval Radio Sta, Dimona Radar Facility, Kiev TV Tower
Lualualei VLF transmitter Wikipedia
VLF transmitter Lualualei is a facility of the United States Navy near Lualualei, Hawaii transmitting orders to submerged submarines in the very low frequency (VLF) range. VLF transmitter Lualualei, which operates under the callsign NPM on 21.4 kHz and 23.4 kHz, uses an antenna consisting of two guyed masts, each 458.11 metres (1503 feet) tall. Both masts, built in 1972, were not only the tallest towers in the Western hemisphere at the time, used for military purposes, they are also the tallest towers used for long wave transmissions in the Western hemisphere and since the collapse of Warsaw Radio Mast perhaps the tallest structures electrically insulated against ground.
Both masts are umbrella antennas. They are fed by an overhead cable, fixed to the mast at one end, and to a small mast near the helix building at the opposite end. As the small mast is grounded, the feeder is attached to it with an insulator in the span field.