North Atlantic Radio System

Lore & Background

The need for NARS arose from the unreliability of an earlier undersea data cable system stretching from Thule airbase in Greenland via Cape Dyer to Newfoundland, Canada, which was frequently cut by trawlers and icebergs. The initial troposcatter system, code-named Pole Vault, had been constructed starting in 1954, became operational in 1955, and was extended in 1956. Pole Vault was gradually shut down after 1962 with the introduction of the SAGE system. Construction of the large BMEWS radars then called for new powerful troposcatter communication stations, leading to NARS.

NARS sites used quad diversity—polarity, space, frequency, and combiner diversity—typical for difficult troposcatter paths. Each set consisted of two transmitters and four receivers for redundancy and improved signal-to-noise ratios. The vacuum tube technology proved time-consuming to maintain at high efficiency. Levels of service were extremely variable with weather and finicky equipment frequently causing loss of connection; improvements came through better maintenance procedures but did not change significantly until the introduction of solid state technology.

The system was closed down in 1992 after 30 years of service. The advent of satellite communications made troposcatter networks obsolete, but NARS was closed early due to the loss of the DYE-2 DEW Line station in 1988, severing the network's connection with the rest of the DEW line. Site 46 also had to close to make way for the new BMEWS Phased Array Radar at RAF Fylingdales.

Reader's Guide

NARS represented a critical Cold War communications backbone, enabling the transfer of radar data from remote Arctic sites to NORAD headquarters in Colorado at a time when satellite links were not yet available. Its use of tropospheric scatter technology allowed reliable over-the-horizon communication across difficult terrain and weather, where HF, VHF, and microwave relay stations were almost impossible to construct and maintain. The system's quad diversity configuration and high-power transmitters (up to 50 kW) were typical of the era's most advanced troposcatter engineering. Despite frequent outages due to weather and vacuum tube maintenance, NARS achieved a data rate of 9.6 kbit/s, considered very fast at the time. The system's closure in 1992 marked the end of an era for large-scale military troposcatter networks, overtaken by satellite communications. The five sites—in Iceland, the Faroe Islands, Scotland, and England—were gradually demolished or repurposed, with only concrete foundations remaining at some locations. NARS is notable as a direct successor to the Pole Vault system and as a component of the larger DEW Line and BMEWS infrastructure.

Did You Know?

• NARS was built by Western Electric (AT&T) and maintained under contract by ITT Federal Electric Corporation.
• Site 42 in Iceland was the entry point for the SOSUS system.

The Ionosphere as a Natural Mirror

Shortwave radio occupies the frequency range from 3 to 30 MHz, sitting between the medium frequency band and the lower edge of VHF. What makes this band uniquely powerful is its interaction with the ionosphere, a layer of electrically charged atoms high in the atmosphere. When shortwave signals are aimed upward at an angle, they bounce or bend back toward Earth, reaching listeners far beyond the visual horizon. This phenomenon, known as skywave or "skip" propagation, allows a single transmitter to project its signal across continents. By contrast, higher-frequency radio waves travel in straight lines and are constrained by the roughly 64-kilometre visual horizon. The absence of a single official band boundary, though the entire high-frequency spectrum is always included, gives operators some flexibility in how they define the usable range. This natural atmospheric mirror is the fundamental reason shortwave has served as humanity's longest-reach wireless medium for nearly a century.

Marconi's Yacht and the Birth of Beam Wireless

In the early 1920s, frequencies above 1.5 MHz were widely dismissed as impractical for long-distance work. Guglielmo Marconi challenged that assumption by tasking his assistant Charles Samuel Franklin with a systematic investigation at Poldhu Wireless Station in Cornwall. Using a 25-kilowatt setup and a large antenna, Franklin completed nighttime transmissions on roughly 3 MHz to Marconi's yacht Elettra in the Cape Verde Islands during the summer of 1923. The following year, Marconi himself was "astonished" to receive clear signals day and night on about 9.4 MHz from Poldhu to Beirut. Franklin's subsequent invention of the curtain array aerial system made directional transmission practical. By late 1926 the UK-to-Canada Beam Wireless Service was in commercial operation, with routes to Australia, South Africa, and India following in 1927. These circuits formed the backbone of the Imperial Wireless Chain, a project contracted with the British General Post Office in 1924.

Disrupting the Cable Monopoly

The rapid adoption of shortwave in the 1920s dealt a severe blow to the transoceanic cable industry. By 1928, more than half of long-distance communications had shifted away from undersea cables and aging longwave wireless installations toward the cheaper, more efficient shortwave stations. Cable companies began hemorrhaging revenue in 1927, prompting the British government to convene the Imperial Wireless and Cable Conference the following year to address the competitive threat posed by Beam Wireless. The conference's recommendation led to the 1929 merger of all overseas cable and wireless assets of the Empire into a single entity, initially called Imperial and International Communications Ltd. and renamed Cable and Wireless Ltd. in 1934. Yet the cable industry staged its own comeback in 1956 with TAT-1, the first voice-frequency cable across the Atlantic, offering 36 high-quality telephone channels. Successive higher-capacity cables worldwide soon rendered shortwave economically unviable for commercial communication, though some longwave stations lingered into the 1960s.

From Propaganda to the Front Lines

For decades, shortwave broadcasting was the primary conduit for delivering news, music, and political messaging across entire continents, often serving as a deliberate propaganda instrument aimed at foreign audiences. Even as satellite radio, cable, and Internet streaming have largely supplanted shortwave for routine long-distance program distribution, the medium retains a stubborn relevance. In conflict zones such as the Russo-Ukrainian war, a single shortwave transmitter can push signals over thousands of miles, making government censorship extraordinarily difficult. The band also remains a workhorse for long-distance aviation and marine communications, and amateur radio operators continue to exploit skywave propagation for two-way international contact, hobby, education, and emergency service. Meanwhile, a dedicated community of shortwave listeners persists, tuning in to fringe stations that no other platform reaches. The medium's very simplicity — one transmitter, the ionosphere, a receiver anywhere on Earth — ensures it will outlast more technologically elaborate distribution systems.