Since the late 1970s, a low buzzing tone has been transmitting nearly constantly somewhere in the shortwave band, at about 4625 kHz. Officially designated UVB-76, it is known colloquially as “The Buzzer.” For decades, it mostly droned on without attracting much attention outside of a small group of radio enthusiasts who tracked it compulsively. Then, at sporadic intervals—typically at times of increased Russian military activity—a voice emerges from the static and reads a series of names and numbers. There is no further explanation. The tone returns. After a momentary outburst, the internet settles down.
The news about that station is outdated. The amount of company it has been receiving lately is less expected. Over the past two years, shortwave listeners and SDR enthusiasts who spend their evenings sweeping the spectrum with modest receivers and open-source software have documented an increasing number of reports of unexplained transmissions, phantom voices on abandoned frequencies, and number sequences appearing on bands that should be empty. People who are keeping a close eye on this feel that something has changed, however it’s difficult to agree on exactly what has changed.
For some of what is being heard, the geopolitical explanation is the simplest and most likely the most plausible. After the end of the Cold War, numbers stations—those tedious, automated broadcasts that read out encrypted sequences to intelligence assets in the field—remained in operation for a long time. They adjusted. The activity tends to increase when international tensions rise, probably because agents need to be resupplied with orders and shortwave is still one of the most difficult communication channels to intercept and clearly attribute.
Although it is rarely easy to draw clear connections between a frequency anomaly and a particular operation, a number of experts monitoring signals intelligence have observed similarities between particular transmission spikes and military escalations in Eastern Europe and the Middle East.
This is further complicated by solar activity. Strong geomagnetic storms that interact with the ionosphere in ways that can push radio signals remarkable distances—far beyond their normal propagation range—have been caused by the sun’s exceptionally active recent past. Under the correct atmospheric circumstances, a local FM broadcast that is supposed to go thirty miles can skip across the Atlantic.
A signal bounced in from thousands of miles distant can suddenly be carried by an obscure shortwave frequency that has been inactive for years. It’s not espionage, but physics. However, the two theories seem similar from the outside when a receiver detects an unknown voice communication on a seemingly empty frequency, which is part of what makes this moment so really difficult to interpret.
The technological aspect of this is also altering the situation. Anyone willing to invest $100 and a few evenings learning the program can now have considerable spectrum monitoring capabilities thanks to software-defined radio. That is a significant change. Unusual transmissions could have gone unnoticed ten years ago, save for a small group of devoted enthusiasts. Shortwave abnormalities are now timestamped, documented, and submitted to forums in a matter of minutes. It’s possible that the number of weird transmissions hasn’t really increased as much as it appears. This could be due in part to the fact that a lot more people are listening than ever before, picking up signals that would have gone unreported in the past.
