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The 10th Mountain Division and Fort Drum Museum staff is working on a future exhibit to highlight the Army Experimental Station and the training of sonic deception Soldiers at Pine Camp (now Fort Drum) during World War II.  Photos, clockwise from top left: Magnetic wire audio recorders used to record sound such as tank engine noises at Pine Camp; the Ghost Army patch; a mobile weather station on an Army Jeep; Personnel testing the distance of sound projection at the Army Experimental Station, Pine Camp; an M-10 Tank Destroyer with sonic projection equipment; retired Lt. Col. Darrel Rippeteau, when he served as a Signal Corps captain at the Army Experimental Station in 1944. (10th Mountain Division and Fort Drum Museum archive)


Soldiers train in art of sonic deception
at Pine Camp during WWII: 'Ghost Army'


Mike Strasser

Fort Drum Garrison Public Affairs


FORT DRUM, N.Y. (Nov. 2, 2020) – Seventy-five years ago, the Army Experimental Station (AES) closed up shop at Pine Camp (now Fort Drum). For decades, only those with top-level clearance knew the story of what they accomplished here.

Still today, there are a few missing chapters, but the 10th Mountain Division and Fort Drum Museum staff is making progress in developing a clearer narrative about this once super-secret organization.

Sepp Scanlin, 10th Mountain Division and Fort Drum Museum director, said that a recent donation of documents and photos from the family of retired Lt. Col. Darrel Rippeteau – the former AES operations officer who was stationed here in between 1944-1945 – is shedding new light on Pine Camp training. Their research will be part of a permanent exhibit, focusing on the AES and sonic deception training, when the museum opens at its new location next year.

“Basically, we just want to shine a light onto this amazing history of Pine Camp, and the innovative training that happened here,” Scanlin said. “To me, it’s seeing this continuity that Pine Camp and Fort Drum has continued to serve as a location for some pretty high-end, unique Army innovation.”

The history

On Jan. 20, 1944, the U.S. Army’s 23rd Headquarters Special Troops activated with the sole mission of deceiving German forces in the European theater during World War II.

Known as “The Ghost Army,” these Soldiers used inflatable tanks and artillery, sent false radio transmissions, and blasted audio recordings of troop movement and construction to create phantom forces that misled the enemy on American troop strength and locations.

The 23rd Headquarters Special Troops included a “sonic deception” combat unit – the 3132nd Signal Service Company – which activated and trained at the Army Experimental Station in March 1944 at Pine Camp, with the 3133rd Signal Service Company.

For their deception to work, state-of-the-art recording techniques and equipment had to be developed to produce soundtracks that were impossible to distinguish from the real thing. The technology was developed at Bell Labs in New Jersey, and civilian advisers were sent to Pine Camp to assist with the training.

“There is a confluence of things that made this the right place,” Scanlin said. “We’re the largest military installation close to Bell Labs, this was a massive armor training facility so they could train on the equipment they would use, and they could record the sounds they needed right here.”

Scanlin said that some of the most complex, technical training for the Ghost Army was conducted at Pine Camp.

“The unit mission for the AES was sonic deception, and this is where they turned the concept into reality in a tactical environment,” he said. “Soldiers would have had to learn how to use this highly technical equipment, and make it work in different environments and situations. We have pictures of Soldiers angling speakers on an M-10 Tank Destroyer, so they practiced how they would project the sound over long distances.”

Soldiers also were trained to operate a mobile weather station because – along with terrain and distance – weather would determine how loud to project the sound. A photo of this training is captioned: “Weather jeep to measure conditions related to the travel of sound at ground level.”

“They had the science to know the weather conditions and if what they were doing would even reach the enemy,” Scanlin said. “Everything from making that Jeep go to where it needed to go, to setting up the weather tower and taking all the measurements and calculations to get the right answer is what they had to train on.”

There was also a synchronization of effort required to produce sounds of vehicle movement on one track, personnel movement and chatter on another, and maybe a third audio track with other ambient sound – each on its own speaker system. Scanlin said that all that noise wouldn’t be played on one track because people don’t hear that way, and authentic duplication of sound was paramount to mission success.

“I’m really interested in learning more about this technology, and the tactics and techniques they were trying to figure out here,” he said. “We’ve got access to some of that now. I think this is a really profound piece of the story that could have easily been hidden because of the classification. But now we’re beginning to know more about it.”

Renewed interest

By all accounts, the Ghost Army Soldiers proved very successful in their missions overseas, and their efforts were said to have saved thousands of lives.

However, like a ghost, the unit virtually disappeared from existence after the war. Those who served in the 23rd Headquarters Special Troops were not allowed to talk about what they did, and it wasn’t until the 1990s when details of their story became declassified.

The fact that Ghost Army Soldiers trained at Pine Camp isn’t necessarily hidden history, according to Scanlin.

“There was a lot of interest when Philip Gerard’s book ‘Secret Soldiers’ was published back in 2001,” he said. “But it was probably already common knowledge because Lt. Col. Rippeteau was local. He settled in Watertown after the war and retired from the local Army Reserves unit in 1977.”

In 2002, Rippeteau met with James Neville, former Fort Drum curator, to donate a collection of material in the hopes that sharing information would draw further attention to those who served in these secretive units. At the time, Neville compared the amount of known history as having 50 pieces of a 3,000-piece puzzle.

“That’s a pretty good way of putting it,” Scanlin said. “Even today, there is so much we still don’t know. But to me, what we have gotten from the family really adds to the story. Everyone sees the story from the operational perspective of what the Ghost Army did in northern Europe. We’ve really expanded the understanding of what the AES did here and what they contributed to the war.”

Pine Camp revealed

Pine Camp has often been presented as training grounds for armor units and the location of an internment camp for Italian and German prisoners of war camp. The post was generally believed to be inactive around 1944-45 because all troops were fighting the war overseas.

“In reality, there was still some secret training going on in the North Country,” Scanlin said. “The people in the AES were still here working. I have to be believe that it is partly because the Soldiers who had already deployed from here had some success overseas, so now there’s some interest. They proved themselves enough that the AES was still here refining the program and showing off their capabilities.”

Scanlin said that several photos from November 1944 confirm that the Army’s “OSCAR” paratrooper decoys were test-launched at Pine Camp during a demonstration for top military brass. German soldiers were the first to use dummy paratroopers in 1940 during the invasion of Holland and Belgium to incite panic. The British developed their own decoy called “Rupert” before the U.S. codenamed their own.

“Residents in this area were probably aware that this demonstration was happening, but they probably weren’t talking about,” he said. “There was a war going on, and people had a better sense of national security – if someone said not to talk about something, it was highly likely you would not talk.”

Scanlin said that every time the anniversary of D-Day approaches, he is asked what part did the 10th Mountain Division and Fort Drum play in it.

“Well, the answer has always been ‘nothing.’ None of our Soldiers landed on D-Day, but there was training going on at Pine Camp. But now we can talk about the OSCARs, and how they were used on D-Day and that they were tested here.”

Scanlin said that he is eager to learn even more, as he continues to dig through the new collection. This includes articles and newspaper clippings about the Ghost Army, AES and sonic deception; a copy of the official history of the 23rd Headquarters Special Troops; various correspondences, and Signal Corps photographs of Pine Camp and sonic deception Soldiers in training.

“All of this helps to continue this story,” Scanlin said.

Scanlin said that people may become even more familiar with the Ghost Army through a bipartisan effort in the Senate. A resolution was introduced in Congress in April of 2019 to award a Congressional Gold Medal to the 23rd Special Headquarters Troops and the 3133rd Signal Service Company for their service during World War II.

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