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Military Radio-Jamming Showdown: What's Hedy Lamarr Got to Do With It?

When dozens of radio engineers gather in Virginia for the U.S. military’s signal-jamming showdown this week, they’ll be following in the footsteps of a most unusual inventor: Hollywood actress Hedy Lamarr.

In 1942, Lamarr and composer George Antheil patented an anti-jamming method, “frequency hopping,” the basic concept for which is still used today.

Actress and electronic warfare pioneer Hedy Lamarr.

During World War II, radio-controlled torpedoes were critical to the U.S. Navy. They had one drawback, though: their control frequencies could be jammed by the enemy. Lamarr and Antheil had a novel idea: using a roll like the kind in a player piano to change the control signal in 88 frequencies.

Fast forward seven decades, and the U.S. government and network researchers are still building on Lamarr’s frequency-hopping concept.

This week the Spectrum Challenge, a competition sponsored by the Defense Advanced Research Projects Agency, is challenging experts from across the country to develop the latest strategies for defeating radio interference. Four Raytheon employees are competing in the Grand Finals in Arlington, Va., on March 19 and 20. 

A Raytheon engineer out of Fort Wayne, Ind., Andrew Marcum is the lead for the Purdue University team. Marcum worked on the command and control software for Zumwalt Navy destroyers before his present job as a systems engineer on the ARC 231 airborne military radio program for the Army. He’s been with Raytheon for eight years.

The Spectrum Challenge team from Purdue has five members, all of whom are pursuing PhDs in communications and signal processing at the university. One of the team’s most demanding tasks was designing a software radio platform, Marcum said.

“Most of us being electrical engineering students, we have the skills to do all the analysis to build a radio, but actually building a software-defined radio was a bit new to all of us,” he said. Two experts from Raytheon BBN Technologies in Cambridge, Mass., and Arlington, Va., Tony Michel and Pat Bidigare, advised the team on implementation issues early in the competition.

Raytheon's Andrew Marcum uses a spectrum analyzer at Purdue University to examine a radio signal. A signal generator on top of the analyzer is used to inject interference.

Bishal Thapa from Raytheon BBN Technologies in formed a team with his advisor from Northeastern University. Thapa’s PhD work was in communications jamming, so the Spectrum Challenge has been a “fun opportunity” for him to get back to his roots.

His team’s strategy has been to combine feedback from a receiver to modify their signal. Their work paid off: they left the contest’s first live competition in September 2013 with a $25,000 cash prize.

“We pulled many all-nighters preparing for that one,” Thapa said.

The criteria have changed for the final round, with more emphasis on sending information packets and less on jamming.

“In the preliminary round, we jammed as much as possible. This time we don’t want to be quite as aggressive because of the different scenario we’ve been given,” said Thapa.

Raytheon BBN’s Bishal Thapa poses with his team after winning $25,000 in a September 2013 Spectrum Challenge competition.

Radios are even more important now than they were in Hedy Lamarr’s day, supporting   critical military operations, first responder teams, cell phone connections - even opening the garage door. As the number of radios grows, the battle for on-demand, secure communications availability intensifies as well.

Last Updated: 10/08/2014

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