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The WWII Spy Station That Eavesdropped on the Entire World

At first glance, the Chopmist Hill area of Scituate, Rhode Island looks like many rural New England towns. It’s a quiet and heavily forested place, about 20 miles west of the capital city of Providence. The economic hub of Chopmist Hill consists of a gas station and a Dunkin’ Donuts. Driving through the town, there would be no reason to suspect that, in 1946, this peaceful village came very close to becoming the United Nations Headquarters.

The climate was acceptable, and the proximity to Providence, Boston, and New York City was convenient. The most important reason for its consideration, however, was something else. During World War Two, this unassuming district was home to a radio intelligence receiving station far more powerful and effective than it had any right to be: the Chopmist Hill Listening Post. Unique among receiving stations, Chopmist Hill had the uncanny ability to send and receive radio signals from any place on earth, and it has been credited as one most important factors in the Allied’ victory in WWII.

Scituate was in the top two or three locations for the U.N. until the decision was made, as it usually is, by bundles of cash. In the end, David Rockefeller donated the money for the New York site to the U.N., and free money turned out to be a great selling point. Scituate lost the bid for the U.N., but the story of the Chopmist Hill Listening Post remains a fascinating and mysterious piece of history.

By the start of the second world war, radio had moved from a sometimes-useful technological marvel to an indispensable part of both civilian life and military logistics. Radio allowed for near-instantaneous communication, and in a war fought on multiple fronts by multiple powers, the speed and ease of radio became vital to war efforts for the Axis and Allies alike.

Radio listening station in 2018

The Suddard farmhouse in 2018. This is what top secret spy stations look like.

The Federal Communications Commission oversaw radio intelligence operations. We might now think of the FCC as the ones selling our grandmothers to Verizon, and mercilessly mocked by the other three-letter-agencies at their annual “super secret potluck picnic” (probably), but at the time, the FCC’s Radio Intelligence Division (RID) was a highly effective counter intelligence task force during WWII. The RID constructed 13 listening posts across the U.S. including the station at Chopmist Hill, which proved to be the most effective by far.

Supervising the Chopmist Hill Listening Post was RID agent Thomas B. Cave. Finding the location to have radio reception far surpassing his hopes, Cave settled on the 730-foot-tall hill in north Scituate as the site for his radio station. The FCC leased the Suddard-family farmhouse and in 1940, a full year before the U.S. entered the war, began construction on what would prove to be a major factor in the Allies’ victory.   

Cave and his team ran 85,000 feet of radio wire through the 186-acre property and erected a vast array of antennas. Telephone poles were sunk deep enough to be hidden by the surrounding trees. The inside of the farmhouse was stacked with radio receivers labeled with the names of distant cities: Cairo, Berlin, Tokyo, Moscow and more.

Throughout the course of the war, between 30 and 40 RID employees worked around the clock to sift through as many as 400 radio signals a day. The radio operators recorded coded messages and sent them to Washington for analysis. After the war, Thomas Cave was asked how far his radios could reach. He replied “Sydney, Australia. That’s about the farthest place there is.”

The remains of the listening post antenna and guard house

The remains of the radio antenna and guard house, all that’s left of the listening post’s radio antenna array.

The list of Chopmist Hill’s accomplishments is staggering. The Imperial War Museum in Bohn, Germany is quoted as saying “Chopmist Hill won the war for the allies.” That’s a bold statement, but the Scituate station’s record seems to attest to it.

Cave and his team intercepted “virtually all German spy transmissions from inside the United States, leading to essentially zero acts of sabotage within the U.S. They were also often the only station able to hear “mayday” signals from downed aircraft in the ocean and successfully directed countless search and rescue operations.

The listening station tuned in to weather reports coming out of Berlin, a much more guarded secret and useful prize than might be imagined, and relayed this information to the British intelligence agency Ultra, who used it to plan bombing raids across Germany in the most ideal conditions.

The British transport ship Queen Mary was docked in Rio De Janeiro, about to depart from Brazil to Australia with 10,000 allied troops aboard. Chopmist picked up German U-Boat transmissions from the waters near Rio, and learned of plans to sink the British ship. The Queen Mary was alerted, plotted a different course, and 10,000 soldiers’ lives were saved.

In North Africa, German Field Marshal Erwin Rommel, the “Desert Fox”, commanded the Afrika Korps tank divisions. Rommel was a brilliant tactician and seemed poised to win the African front. In 1942, Chopmist Hill realized something incredible that would change the outcome of the fight for North Africa. They were able to intercept the tank-to-tank communications of the Afrika Korps, gaining direct and exact knowledge of tactics, supplies, and other logistics. To reiterate, the communications between individual tanks, very close to each other, in North Africa, were being picked up by a farmhouse many thousands of miles away. Chopmist relayed this information to British intelligence, and Rommel was caught off-guard and defeated at El-Alamein. Soon after, the African front was won.

Chopmist once foiled a ridiculous plot by the Japanese military to weaponize hot-air balloons. The Japanese loaded pounds of TNT onto balloons and floated them over the United States, hoping that they would somehow land in a strategic location and not a field, or the woods, or a lake. Chopmist Hill located them through the radio frequency trackers attached and promptly alerted the air force, who dispatched the balloons without trouble.

The station’s reputation became such that U.S. troops began asking for all intelligence to be confirmed by Chopmist Hill. The Pentagon was incredulous that a single listening post could be that efficient, so to test Chopmist’s claims, they set up a fake spy station within the Pentagon itself. It took Chopmist only seven minutes to alert the Pentagon of the “spy” in their midst.  

Thomas Cave said that there was nothing particularly special about the place itself, that it was merely the technology used that was responsible for Chopmist Hill’s extreme ability. However that leaves some inconsistencies. For one, Cave previously said that Chopmist Hill had the best radio reception in the country. Moreover, there were 12 other stations, none of which even came close to Chopmist’s effectiveness. There would also be no reason for the U.N. interest if the results could be replicated elsewhere.

According to The Providence Journal, it was a combination of “geographic and atmospheric anomalies” that led Cave to choose Scituate in the first place. The nature of these anomalies are left to the imagination. It’s certainly a strange area, very close to a large concentration of ghost stories, (including Rhode Island’s only officially haunted location, as recorded by the 1885 census), and has unique geology. An aeromagnetic map of Rhode Island shows a circle of drastically increased magnetism slightly south of Chopmist Hill, is it possible that some geological feature was scattering competing signals, decreasing interference and allowing Chopmist to tune in to even the faintest signals?

Aeromagnetic map of Rhode Island showing anomaly near Chopmist Hill

The big purple magnetic pimple in the middle of the map is directly south of Chopmist Hill. Credit: U.S. Geological Survey

I grew up in western RI, a few miles from Chopmist Hill, and first became interested in this story years ago, when I heard a second-hand account of a man who had delivered milk to the listening post when he was a boy. He said after the war was over, he recognized a picture of a scientist with whom he’d had a lengthy conversation while making a delivery. He claimed that J. Robert Oppenheimer, the father of the nuclear bomb, and recurring character in many stories about fringe science, was at Chopmist Hill.

Besides The Manhattan Project, Oppenheimer was involved throughout his life in many other advanced and fringe areas of study. If he was at Chopmist, it becomes an even better legend and fuel for even more wild speculation, which is some of the best fun a person can have.

I really want this to be true. In writing this story, I pored through historical records at the Scituate library looking for something, anything, that could place Oppenheimer at Chopmist. Unfortunately, there is little information on the listening post in general, and finding the names of even the regular employees at Chopmist has proved to be a herculean task. Some of the information on Chopmist is still classified, and will remain that way for the foreseeable future.

However, we know that in 1942—the same year that Chopmist Hill began intercepting Erwin Rommel’s tank communication in North Africa—Robert Oppenheimer began recruitment for The Manhattan Project. By 1945 he had 4,000 employees working on the project. A quote from Oppenheimer on his recruitment process shows up in his obituary:

“To recruit staff, I traveled all over the country talking with people who had been working on one or another aspect of the atomic-energy enterprise, and people in radar work, for example, and underwater sound, telling them about the job, the place that we are going to, and enlisting their enthusiasm.”

There were scientists from Rhode Island and Massachusetts who were part of the Manhattan Project. It doesn’t seem too far fetched to believe that if he made his way to Rhode Island, Oppenheimer may have made a stop at the super powered radio station. This is circumstantial evidence at best, and proves nothing except the possibility of the Oppenheimer connection.

So, the mystery remains. Whether it was advanced technology, strange geologic forces, or something else that made Chopmist Hill so special might never be known. The farmhouse will be painted over. The radio tower will continue to rust. The secrets of Chopmist Hill, like so many secrets swaddled in the New England forest, will stay hidden. Only one thing can be said for certain, when the world was at war, a few dozen men and women in an old Rhode Island farmhouse reached into the ether and did something impossible.