Although I was never been aboard an EC-130H Compass Call, I had the utmost respect for it. During a memorable rotation at the National Training Center (NTC), located on Fort Irwin, I got to help make calls for fire from one of these planes flying out from Davis-Monthan Air Force Base in Arizona.
Of course, the “fire” was electromagnetic (EM) energy — several hundred watts, just a tiny fraction of its potential power — but this was still very effective jamming. We forced the opposing force (OPFOR) to change frequencies nineteen times during their attack, contributing to their defeat. The OPFOR reconnaissance commander was unable to communicate important information at exactly the right time. We caught the main body in a notional fire sack, exactly as we had planned and hoped. This is a thing that hardly ever, ever happens.
Stationed at Fort Irwin, the 11th Armored Cavalry Regiment is probably the single most experienced military unit in the world when it comes to dealing with tactical radio interference. In order to keep up this pressure, our collectors had to be on top of their game, find the OPFOR whenever they “jumped” to a new frequency, gauge how effective the jamming was on the new channel, and then do it all over again. As always, training matters at least as much as equipment.
OPFOR almost never loses a battle. The whole point of NTC is that soldiers and units “train to the point of failure,” learning vital lessons from defeat in virtual battles against a veteran opponent. This time, however, the visiting task force annihilated their foes. The Compass Call had been so effective that it was taken away from us after that battle, and for the rest of our battles that cycle, we were only allowed to use our ground jammers. (We still kicked ass.)
Of course, that was decades ago, when the Smashing Pumpkins were in their prime and so was the old Compass Call. The EC-130H is being retired from service now. Based on the more famous Cold War cargo plane, it had dozens of external antenna wires strung from the tailplanes to the fuselage, giving it an ungainly, cobwebbed appearance.
Compared to their predecessor, the replacement Compass Call, EC-37B, is a beauty queen, being built on a sleek Gulfstream G550 platform that is 220 miles (354 km) per hour faster than the old plane. Which is not to call the new Compass Call pretty. Those bulging “cheeks” on the fuselage, containing solid-state arrays, will not be winning any aeronautical beauty contests.

Unlike many tactical aircraft, this one is not meant to hug the terrain, but to dominate from on high. Flying the Compass Call at altitudes of 50,000 feet (15,000m) or more is not only faster than low-level flight, it also “lowers the radar/optical horizon and provides a greater field of regard for the aircraft’s electronic, radar and optical sensors, allowing a larger area to be surveyed in a single mission.” Of course, this also means the potential target zone for jamming radios and radars gets bigger the higher they fly — they can hit targets from “standoff range.”
Technological advances have made the change from a large cargo plane to a business jet possible. “Clearly, one of the biggest challenges to cross-decking Compass Call from the EC-130H to the much smaller EC-37B platform was reducing the size of the systems and its on-aircraft support requirements,” John Haystead writes in the February 2023 Journal of Electromagnetic Dominance. “Given that the current platform is itself packed full of equipment, this was a substantial undertaking.”
Software-defined radio technology and open source architecture have greatly reduced the size, weight, and power (SWAP) requirements of the system, helping to “squeeze” nine tons of equipment down to just four tons. The G550 also produces more than enough electrical power for mission requirements.
BAE Systems is the primary contractor integrating the Compass Call system with the new aircraft. Along with L3Harris Technologies Inc., they carried out a successful test flight of the Small Adaptive Bank of Electronic Resources (SABER) last April. A simulator has been set up at Davis-Monthan, home of the 55th Electronic Combat Group, to train flight crew on the system.
While only ten of these new planes are scheduled for construction, they will have as much collective EM firepower as the previous 14 Compass Call aircraft. Automation and an improved interface reduce the workload on the aircrew. With more than three times the fuel range of a C-130, the G550 can also loiter much longer than its predecessor.
Nor is it necessary for the United States to do everything themselves. As I have explained before, EW is emerging as a vital area of inter-service and coalition integration. Compared to bombers or fighters, these systems are also relatively cheap. NATO members such as Italy can expand their material contribution to the alliance more with one EW aircraft than a whole squadron of fighters. Better yet, one aerial EW platform with standoff capability multiplies the power of a single squadron by jamming early warning radars, missile radars, ground-to-air radio communications with interceptor pilots, and so on.
Compass Call does not directly cause enemy objects to explode. EW is a “force-multiplier,” a capability that makes other weapons more powerful. The one opportunity I had to experience tasking a Compass Call perfectly demonstrated the principle: our tanks, anti-tank missiles, and artillery were far more effective than they would have been without that help coming down from on high.