Jim Creek Naval Radio Station

Buildings and structures in Snohomish County, WashingtonCommunications and electronic installations of the United States NavyMilitary installations in Washington (state)Naval installations in Washington (state)

Jim Creek Naval Radio Station is a United States Navy very low frequency (VLF) radio transmitter facility at Jim Creek near Oso, Washington. The primary mission of this site is to communicate orders one-way to submarines of the Pacific fleet. Radio waves in the very low frequency band can penetrate seawater and be received by submerged submarines which cannot be reached by radio communications at other frequencies. Established in 1953, the transmitter radiates on 24.8 kHz with a power of 1.2 megawatts and a callsign of NLK, and is one of the most powerful radio transmitters in the world. Located near Arlington, Washington, in the foothills of the Cascades, north of Seattle, the site has 5,000 largely forested acres (2,000 ha).

Excerpt from the Wikipedia article Jim Creek Naval Radio Station (License: CC BY-SA 3.0, Authors, Images).