A couple of weeks ago, in the runup to the presidential alert cellphone users received on October 3, I wrote about the history of America’s various early-warning systems, from Conelrad to EBS to EAS to the Wireless Emergency Alert system. The goal of each was/is to transmit critical information to the public immediately and all at once, and to get people to shelters where they’d have a chance to survive an attack.
The question of what would happen after an attack was less widely discussed. Conelrad and, after 1963, the Emergency Broadcast System, would theoretically be able to continue transmitting emergency information. But what if people had to remain in underground shelters for days or weeks? How would they get emergency signals down there, where regular radio signals don’t go? And what if radio stations themselves were devastated? Nuclear weapons generate electromagnetic pulse radiation (EMP) that is capable of crippling the electrical grid, telephone systems, and practically everything that runs on electricity. Even if your town didn’t get incinerated, a big-enough EMP in the atmosphere could turn back the technological clock 150 years.
In the 60s and early 70s, federal emergency planners worked on a refinement of the Emergency Broadcast System intended to respond to these issues and improve the warning system: DIDS, the Decision Information Distribution System. It would be a network of radio stations spread across the country with the sole purpose of delivering emergency messages to the public, and secure enough to keep broadcasting even after widespread devastation. Unlike Conelrad and EBS, DIDS would not use existing broadcast stations. Instead, it would build its own. The stations would broadcast not on the standard AM or FM bands, but on the longwave band at 167, 179, and 191 kHz. (The standard AM band begins at 540 kHz.) The advantage of using longwave was that unlike standard-band signals, longwave signals travel mostly along the curvature of the earth. Signals could reach underground and underwater over long distances and wouldn’t depend on a network of towers, as EBS did, given that after a nuclear exchange, a lot of those towers would likely be turned to rubble.
A 10-station network was proposed, with stations to be built in places such as Mount Joy, Pennsylvania; Starke, Florida; Winslow, Arizona; Hermiston, Oregon; and Mazomanie, Wisconsin (just west of my town, Madison). It would be powerful enough to cover the entire lower 48, although just what Alaska and Hawaii were supposed to do was a question left open. In the event of an attack, activating stations in Colorado and Kansas would send a “go” signal to the network, which would supposedly be operational within 30 seconds. Connections to the Pentagon’s early-warning radar systems would give the network the capability of telling people where attacks were occurring and where it was safe, but how that was going to work is unclear to me. Planners claimed that by the time the network was completely built, in 1979, it could save the lives of 10 to 17 million people, and maybe another 10 million if additional stations were built.
A prototype station was built: WGU-20, licensed to Chase, Maryland, but located near the Army’s Aberdeen Proving Ground on Chesapeake Bay northeast of Baltimore. It went on the air in 1973 on 179 kHz with 50,000 watts of power from the first all-solid-state radio transmitter Westinghouse ever built. It had a 700-foot tower, was partially underground to guard against EMP and blast effects, and cost $2 million to build. That $2-million figure explains in part why the rest of the network was never built. But there was another problem: few people owned a longwave radio. The plan was to build emergency receivers into new radios and TV sets and offer an add-on device to retrofit old ones. To increase awareness and encourage people to use the system, it was given a benign name, Public Emergency Radio (PER), and a marketing campaign starring a cute dog mascot named PERki. It didn’t help, and at mid-decade, PER was abandoned.
But WGU-20 soldiered on. At first, it broadcast only a continuous series of time-checks and station identifications, and was quite mysterious to the small number of longwave listeners who found it, since the feds had never explained what it was for. After its purpose became public, it added weather updates for the East Coast; in that way, it was not unlike today’s NOAA weather radio stations. WGU-20 went off the air in 1990, but its tower wasn’t demolished until 2011. You can read more about it and hear what it sounded like here. Read more about America’s alert-program history in this fascinating piece from Wired here.