The Dieppe Raid And What It Taught Us About Jamming

By John Oncea, Editor

A disastrous amphibious raid at Dieppe on the northeastern coast of Normandy in August 1942 taught Allied leaders what not to do on D-Day. Lessons learned from the failed raid are still shaping military decisions today.

Everything Everywhere Daily is a wonderful podcast that inspired me once before. Well, they did it again, this time telling the story of the Dieppe Raid, also known as Operation Jubilee, which took place on August 19, 1942, and was a total disaster.

Despite being a massive failure, the Allies applied what they learned from their mistakes during that raid to plan and execute the invasion of Normandy two years later. Today, many of the lessons learned from the doomed invasion at Dieppe are incorporated into modern warfare – including radar jamming.

Setting The Stage

“The Allied situation in the spring of 1942 was grim,” reports Veterans Affairs Canada (CAV). “Allied forces were no longer in Western Europe after being forced to retreat from Dunkirk in June of 1940. Germany’s forces had also invaded deep into Russia. And, in North Africa, the British Eighth Army had been forced back to Egypt.”

Europe was almost entirely under German occupation, well-entrenched and lying in wait. The Allies knew now was not the time to mount “Operation Overlord,” the full-scale invasion of Western Europe that ultimately took place in June 1944 and is better known as D-Day, or the Battle of Normandy.

“Instead, the Allies chose to mount a major raid on just the French port of Dieppe,” CAV reports. “It was designed to gain experience and test the equipment needed to launch an immense amphibious assault that would one day be necessary to defeat Germany.”

It also was to be manned by mostly Canadian troops whose involvement in World War II was primarily limited to guarding Great Britain, according to Everything Everywhere Daily. This mission, then, would be the first real combat Canadian forces would see and would unfortunately serve as a lesson for what not to do in amphibious operations.

By Noon, It Was Over

Operation Rutter was set to take place in July 1942, but bad weather stood in the way. Debate ensued as to whether or not to abandon the raid and, eventually, the operation was back on, this time given the code name Jubilee.

“The Raid on Dieppe took place on the morning of August 19, 1942. The forces attacked at five different points on a front roughly 10 miles long,” reports CAV. “Four simultaneous flank attacks were to go in just before dawn, followed half an hour later by the main attack on the town of Dieppe itself.

“Canadians were the force for the frontal attack on Dieppe and also went in at gaps in the cliffs at Pourville, two-and-a-half miles to the west, and Puys to the east. British commandos were assigned to destroy the coastal batteries at Berneval on the eastern flank and at Varengeville in the west.”

In the early hours, the assault force heading toward the coast of France came across a small German convoy unexpectedly. This resulted in a violent sea fight which created a loud noise, subsequently alerting the German coastal defenses, particularly at Berneval and Puys.

As the Germans were prepared to defend their territory, the element of surprise was lost. The crafts carrying No. 3 Commando were scattered, and most of the unit never made it to the shore. Those who did manage to reach the shore were quickly overpowered. However, a small group of 20 commandos were able to get within 200 yards of the German battery. Their precise sniping skills prevented the German guns from firing on the assault ships for two and a half crucial hours before they were safely evacuated.

“The main attack was made across the pebble beach in front of Dieppe,” CAV reports. “It was timed to take place a half-hour later than the assault on its flanks. The German troops, concealed in clifftop positions and buildings overlooking the promenade, were well prepared for the Canadians.”

By early afternoon, Operation Jubilee was over. With the Germans fully alerted and the Canadians lacking adequate naval and air support, “907 Canadian soldiers had died on the beach, 586 had suffered wounds, and 1,946 had fallen into German hands,” according to Canada’s National History Society (CNHS). “British Commandos and Royal Marines had forty-five killed and 197 wounded or captured. The Royal Navy lost 28% of the vessels used in the raid and 550 officers and ratings. The Royal and Royal Canadian Air Forces had 106 aircraft shot down, the heaviest single day’s losses since the beginning of the war.”

Of the 4,963 Canadians who embarked on the operation, only 2,210 returned to England.

Lessons Learned

Did Operation Jubilee’s failure help D-Day to succeed? “Yes, to some extent,” writes CNHS. “After Dieppe, everyone recognized the need for better planning and a clearer chain of command. Operation Overlord … satisfied those requirements. There was heavy bombing, though it was not hugely successful in destroying beach defenses. There was massive naval gun support, which was successful. There were better landing craft and specialized armored vehicles, and the assault troops were far better trained.”

Beyond helping the Allies better prepare for D-Day, Operation Jubilee revealed how vulnerable radio communications were to jamming by the enemy. German forces were able to jam or intercept many of the radio transmissions made by the Allied forces during the raid, greatly hampering the coordination and effectiveness of the operation but leading the Allies to improve and better secure radio communication going forward.

But the Germans weren’t the only ones utilizing jamming. A secondary objective of the Dieppe Raid “was to discover the importance and performance of a German radar station on the cliff-top to the east of the town of Pourville,” writes Normandy Then and Now. To achieve this, a radar specialist, Jack Nissenthall, attempted to enter the radar station and learn its secrets.

Despite the failure of Nissenthall and his team to overcome radar station defenses, he was able to crawl up to the rear part of the station and successfully cut all the telephone wires leading to it. Consequently, the operators inside had no choice but to use the radio to communicate with their commanders, which was intercepted by listening posts on the south coast of England. This enabled the Allies to acquire crucial information about the improved accuracy, location, capacity, and density of German radar stations situated along the Channel coast.

This valuable intelligence not only helped change the course of the way, but it also helped convince Allied commanders of the significance of developing radar jamming technology.

Jamming With An EA-18G Growler

Jamming is a form of Electronic Warfare (EW) that uses interfering signals to disrupt enemy radars and radios, thereby disrupting control of a battle. “At its simplest, jamming is intended to degrade the ability of radars or radios to perform their tasks, or even prevent them from doing so altogether,” writes Defense Advancement. “The jamming process also harnesses radio signals but does so in such a way as to attack these systems.

“Put simply, jamming uses artificially created radio interference offensively. An example of how jamming works can be witnessed when a car drives under a powerline with its radio on. The sound of the radio suddenly becomes drowned out by interference. This is caused by the electromagnetic radiation from the powerlines.”

The EA-18G Growler is a variant in the F/A-18 family of aircraft that combines the proven F/A-18F Super Hornet platform with a sophisticated EW suite. According to Naval Air Systems Command (NAVAIR), the Growler is the first newly-designed EW aircraft produced in more than 35 years and replaced the EA-6B Prowler. In addition:

• The first Growler test aircraft went into production in October 2004 and made its first flight in August 2006.
• The first production aircraft was delivered on June 3, 2008, to Electronic Attack Squadron (VAQ) 129, the Growler Fleet Replacement Squadron, at Naval Air Station (NAS) Whidbey Island in Washington. Initial operational capability and full-rate production followed in the fall of 2009. In 2010, three squadrons, VAQ-132, 141, and 138, transitioned from the Prowler to the Growler and were declared safe for flight.
• In the last fifteen years, the EA-18G Growler has spanned the globe in support of all major and rapid reaction actions. The Growler’s first baptism of fire came with Operation Odyssey Dawn in Libya in 2011.
• Four U.S. Navy Expeditionary VAQ squadrons uniquely support U.S. Air Force and Navy shore-based operations. All EA-18G squadrons are stationed at NAS Whidbey Island, except for one squadron (VAQ-141) attached to CVW-5, Forward Deployed Naval Force, based at Marine Corps Air Station Iwakuni, Japan.
• Growler Block II is currently in development and will include advances like the Advanced Cockpit System (ACS), and other internal improvements in common with the F/A-18E/F Block III, and enhancements to the Airborne Electronic Attack suite that will enable the EA-18G to outpace current threats and maintain the lead throughout its planned life cycle.

One addition to the Growler’s technological toolbelt is Next Generation Jammer (NGJ), the next step in Airborne Electronic Attack (AEA), something that is needed to meet current and emerging EW threats, counter growing threat capabilities and capacity, and keep pace with the continuous expansion of the AEA mission area, according to NAVAIR. “NGJ is an evolutionary acquisition program providing capability in three increments: Mid-Band, Low Band, and High Band frequencies. Using the latest digital software and Active Electronically Scanned Array technologies, NGJ provides enhanced AEA capabilities to disrupt, deny, and degrade enemy air defense and ground communication systems.

“It brings increased power and jamming capability at longer ranges. Additionally, the system allows for rapid hardware and software updates to counter improving and evolving threat capabilities. NGJ will augment, and ultimately replace, the legacy ALQ-99 Tactical Jamming System that is currently used on the EA-18G Growler aircraft.”

• AN/ALQ-249 Next Generation Jammer Mid-Band (NGJ-MB): As an external carriage AEA capability for the EA-18G Growler, NGJ-MB focuses on the middle-frequency bands of the electromagnetic spectrum. The system comprises two pods per shipset, as well as small hardware and software modifications to the EA-18G Growler aircraft to enable carriage, communication, and employment. NGJ-MB achieved Milestone C in 2021, allowing the program to enter the Production and Deployment acquisition phase. Low-Rate Initial Production I and II contracts were awarded in July and December 2021, respectively. NGJ-MB program is a joint cooperative program between the U.S. Department of Defense and the Australian Department of Defense.
• Next Generation Jammer Low Band (NGJ-LB): As an external carriage AEA capability for the EA-18G Growler, NGJ-LB will use the latest digital and software-based technologies that address advanced and emerging threats in the lower frequency bands of the electromagnetic spectrum. NGJ-LB is currently in the Engineering and Manufacturing Development acquisition phase and is a joint cooperative program between the U.S. Department of Defense and the Australian Department of Defense.

A Closer Look At NGJ-LB

NGJ-LB uses the latest digital and software-based technologies to address advanced and emerging threats in the lower frequency bands of the electromagnetic spectrum. L3Harris developed the NGJ-LB tactical jamming pod which delivers the capability and power necessary to confidently engage enemy air defenses at standoff ranges, optimizing strike force survivability. NGJ-LB provides an extended stand-off range, simultaneous multiple-target engagement, and greater electronic attack effectiveness and will replace the low-band pod that the aircraft carries on the centerline store position under the fuselage.

“Air-defense systems leverage more radars than ever before – each an individual threat that Airborne Electronic Attack (AEA) systems must target – overwhelming the capability of assets currently in the field,” writes L3Harris. “Further, since the early 2000s, there has been a shift from U.S. adversaries toward employing low-frequency tactics to take out aircraft.”

John Ghosh, L3Harris Technologies Business Development director, said, “Some threats employ using lower frequency detection systems. They don’t get the same high-confidence solution they might out of, say, an X-band asset, but it can be good enough to employ a long-distance weapon with its terminal guidance.”

“The NGJ-LB will be extremely important to provide cover to stealth aircraft threatened by the emerging counter-stealth Low Band radars or to counter long-range weapons using low-frequency terminal guidance systems,” writes The Aviationist. In addition, they point out the pod lacks the usual ram air turbine typically used to produce the power required to emit jamming signals. It also mentions that the pod has an air intake duct that is similar to the one found in the Sniper ATP (Advanced Targeting Pod).