Overview of Department of Defense Use of the Electromagnetic Spectrum

Every modern weapon, from a fighter jet to a foot soldier’s radio, depends on an invisible resource that cell-phone carriers covet just as fiercely: the electromagnetic spectrum. The U.S. military is its single largest federal user, and by 2021 the collision between national defense and the commercial hunger for 5G had become one of the most consequential policy fights in Washington. This report is the map Congress used to navigate it. Overview of Department of Defense Use of the Electromagnetic Spectrum is Congressional Research Service Report R46564, dated July 16, 2021. Coordinated by John R. Hoehn, an Analyst in Military Capabilities and Programs, and written with Jill C. Gallagher and Kelley M. Sayler, it is a nonpartisan briefing prepared solely at the direction of Congress, dense with citations and deliberately non-prescriptive.The report opens by establishing the stakes. The spectrum, the full range of radio waves, microwaves, infrared, visible light, and beyond, underpins military communications, navigation, radar, and intelligence, surveillance, and reconnaissance. DOD is allocated roughly 40 percent of federally assigned spectrum, including prime bands in the 1 to 6 GHz range coveted for mobile telecommunications, even as the FCC’s C-Band Auction 107 drew some $81 billion from commercial bidders. Squeezing the military from the other side were adversaries, principally China, Russia, Iran, and North Korea, who had spent thirty years studying how the United States wages war and built electronic-warfare and anti-access systems to deny its use of the spectrum in contested regions.Much of the report is a lucid primer on how the military actually uses the spectrum, from line-of-sight radios and tropospheric-scatter terminals to satellite constellations such as AEHF, WGS, and MUOS, and sensors including radar, LIDAR, and the SBIRS infrared system. It then surveys emerging applications: 5G testbeds, AI-enabled cognitive electronic warfare and dynamic spectrum sharing, laser communications, directed-energy weapons like the Navy’s LaWS and HELIOS scaling toward 300 and 500 kilowatts, and counter-drone systems. It documents a wave of institutional change, the 2019 EMSO Cross Functional Team, Joint Publication 3-85, Directive 3610.01, and the 2020 Electromagnetic Spectrum Superiority Strategy, and devotes an entire appendix to the contentious FCC approval of Ligado Networks over the GPS-interference objections of DOD, the Department of Homeland Security, the Department of Transportation, and other agencies. It closes by laying out framing questions for Congress, from interoperability failures such as the incompatible data links of the F-22 and F-35 to spectrum-sharing arrangements like the Citizens Broadband Radio Service, alongside concepts such as Joint All Domain Command and Control and DARPA’s Mosaic Warfare.This Nimble Books edition faithfully reproduces the full government report and adds a complete editorial apparatus newly prepared for this volume. A Historical Context essay explains the spectrum, the NTIA-FCC management split, and why the issue grew urgent in 2020 and 2021. Two complementary plain-language abstracts open the material to every reader, an accessible explain-it-simply summary and an advanced analytical summary that assesses the report’s synthesis and the limits of its genre. A Glossary defines technical terms, Indexes of persons, places, and concepts aid navigation, and an original computational RKHS knowledge-graph analysis situates the report among related works on defense technology and telecommunications policy.For defense analysts, telecommunications-policy scholars, engineers, students, librarians, and any reader seeking to understand the contest over a finite and invisible national asset, this volume preserves a clear July 2021 baseline whose forward-looking projections can now be tested against the historical record.