While the U.S. military is unlikely to intentionally attack Russian forces in Syria, the situation highlights the importance of suppressing enemy air defenses—one major tactic U.S. flyers have long relied upon is radar jamming, or saturating enemy radars with “noise” and false signals so that they can’t track and fire upon friendly airplanes. The U.S. Navy has relied on the ALQ-99 jamming system for nearly half a century, even as opposing radars grew in ability. However, by the beginning of the next decade it will begin fielding the superior Next Generation Jammer, boasting significant electronic-attack and signal-intelligence capabilities.
The powerful ALQ-99 tactical jamming pod first entered U.S. Navy service in 1971, carried by the EA-6 Prowler, an electronic-warfare variant of the A-6 Intruder carrier-based attack plane with a four-man crew. The U.S. Air Force eventually supplemented the Prowler with faster and larger EF-111 Ravens , informally known as Spark Varks because of the intense static buildup their jammers generated. Both planes proved effective in suppressing air defenses in Iraq and Libya. However, the Raven was withdrawn from service early in 1998, as the imminent retirement of the F-111 fleet made it prohibitively expensive to operate. Seventeen years later, the Navy retired its aging EA-6s  in favor of new EA-18G Growlers—special electronic-warfare variants of the F-18 Super Hornet. The two-seat Growlers are much faster and better armed, but must rely on automation to make up for the reduction in crew size.
The Marine Corps will continue to fly its Prowlers until retirement in 2019, leaving the Growler as the sole remaining tactical jammer. Overall, demand for jamming aircraft has remained high even as the quantity has diminished. The jammers have even proven useful in the war against ISIS by scrambling ISIS communications and disabling roadside bombs .
Jamming, however, is not a panacea against enemy radars—it sharply degrades their effective range but does not neutralize them entirely, and jamming aircraft have to be careful not to get too close to the defenses they are scrambling. Furthermore, while the analog-based ALQ-99 has abundant power, new radars boast greater power as well, and are more capable of switching frequencies and networking with friendly sensors to overcome the effects of jamming.
Enter the Next Generation Jammer program, the first documents for which were released by the Pentagon in 2004, with the aim of bringing jamming into the digital age. The NGJ had originally been envisioned as an automated pod for use on single-seat F-35 Lightning stealth fighters, which would serve in all three branches of the military. However, this concept proved much more expensive and time-consuming than expected—which could summarize be the F-35 program in a nutshell. Instead, the Pentagon eventually decided to focus on re-equipping the Navy Growlers with the new jamming system, and in 2013 chose the design proposed by Raytheon over three major competitors.
The NGJ is designed to work against a full spectrum of radars, but different radars will require different countermeasures, which Raytheon is developing on a staggered schedule. The upcoming Increment 1 pods are designed to jam mid-band engagement radars commonly used by ground-based surface-to-air missiles, which pose the greatest threat to U.S. aircraft today. Once available, the EA-18 will carry two of the mid-band pods—one under each wing.
However, the Growler will retain a single fuselage-mounted ALQ-99 pod optimized for jamming low-band radars until the Increment 2 NGJ pod is ready further into the 2020s. Low-band or surveillance radars have a broader scanning area, and are effective at tracking enemy aircraft—even stealth fighters!—but are too imprecise for targeting weapons. Nonetheless, surveillance radars help the more narrowly focused engagement radars know where to look for enemies, and a forewarned engagement radar can ambush a stealth fighter at short range. Thus, as the number of stealth aircraft swells with the production of the F-35, jamming low-band radars will become more and more important.
Eventually, Raytheon also plans to develop an Increment 3 system for jamming high-band engagement radars, which are common on fighter planes.
The fifteen-foot NGJ pods employ an Active Electronically Scanned Array radar with gallium nitride components  that amplify radio energy. Program manager Capt. John Bailey claimed in a seminar  that the NGJ can generate ten times the radiated isotropic power level of the preceding ALQ-99, and that the signal is “cleaner,” minimizing the collateral interference with friendly signals. Just as importantly, the NGJ can jam multiple frequencies—Captain Bailey claims four times as many—and is designed to be an “agile” jammer, capable of analyzing new enemy signals and adjusting its own frequencies to counter them literally on the fly. Moreover, because the NGJ is a digital solid-state open-architecture system, it can be upgraded with new “threat libraries” of hostile hardware, allowing it to be easily—and cheaply—upgraded to match new adversary capabilities. Finally, the NGJ pods can do all of this without draining power from the Growler carrying it, thanks to its ram air turbine.
The jamming pods also reportedly come with additional bells and whistles, most notably the ability to spy on enemy communications. This would apparently allow the Growler to serve as a potential Signals Intelligence (SIGINT) platform, as well as enable it to double as a communication hub. The NGJ also reportedly comes with cyber-attack abilities to perform a “network invasion” by inserting data packets into adversary systems, a technique that has been demonstrated by an Air Force EC-130 .
Since being approved to develop the NGJ, the NGJ development process has proven relatively fast and efficient . However, a Department of Testing report  notes that the NGJ has yet to be tested in operational conditions and that the pods’ effects on the EA-18 flight performance are unclear. The report also expresses concern that the NGH pods may degrade the performance of the Growler’s ALQ-218 receiver, decrease range and pose an electromagnetic hazard to the fighter’s AGM-88 antiradar missiles.
The NGJ Increment 1 jammers are intended to have initial operating capability around 2021. The Pentagon has already allocated $1 billion for this first batch, with several more billions likely to follow over time. Australia, meanwhile, has invested  $192 million into the program, and intends to eventually fit them on its twelve new Growlers, which will complete delivery later this year.
Eventually, the Pentagon intends to revisit developing a NGJ pod specially for the F-35—but that will likely wait until the late 2020s at the earliest. In the meantime, there is talk of fitting the NGJ to the Navy UCLASS drone to increase the number of available jamming platforms.
As radars and radar-guided antiaircraft missiles continue to grow in range and sophistication, jamming and other forms of electronic warfare will remain vital means for air power to survive over the battle spaces of the future. The Next Generation Jammer is the Pentagon’s attempt to counter new advances in air-defense radars—while adding to its bag of electronic tricks.
Sébastien Roblin holds a master’s degree in conflict resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring .