“Tavajoh! Tavajoh! Tavajoh!” a person’s voice declares, earlier than happening to relate a string of numbers in no obvious order, slowly and rhythmically. After practically two hours, the calls of “Consideration!” in Persian cease, solely to renew once more hours later.
The printed has been enjoying twice a day on a shortwave frequency for the reason that begin of the US-Israel assault on Iran on February 28.
In keeping with Priyom, a corporation which tracks and analyses world army and intelligence use of shortwave radio, utilizing established radio-location strategies, the printed was first heard because the US bombing of Iran started. It has since performed on the 7910 kHz shortwave frequency like clockwork—at 02.00 UTC and once more at 18.00 UTC.
Over the weekend, Priyom stated it had recognized the probably origin of the printed. Utilizing multilateration and triangulation strategies, the group traced the sign to a shortwave transmission facility inside a US army base in Böblingen, southwest of Stuttgart, Germany.
The positioning lies inside a restricted coaching space between Panzer Kaserne and Patch Barracks, with technical operations probably linked to the US military’s 52nd Strategic Sign Battalion, headquartered close by.
That identification narrows the sector, however it doesn’t reveal who’s behind the transmissions or who they’re meant for.
The 2-hour-long transmission is split into 5 to 6 segments, every lasting as much as 20 minutes. Every opens with “Tavajoh!” earlier than shifting right into a string of numbers in Persian, generally punctuated with an English phrase or two. 5 days into the printed, radio jammers have been heard making an attempt to dam the frequency. The next day, the transmission shifted to a unique frequency—7842 kHz.
Radio communication consultants imagine the printed is probably going a part of a Chilly Conflict–period system often known as quantity stations.
The Return of the Numbers
Quantity stations are shortwave radio broadcasts that play strings of numbers or codes that sound random—just like the one now heard in Iran. “It’s an encrypted radio message utilized by international intelligence companies, typically as a part of a fancy operation by intelligence companies and militaries,” says Maris Goldmanis, a Latvian historian and avid numbers stations researcher.
Quantity stations are mostly related to espionage. “For intelligence companies, you will need to talk with their spies to assemble intelligence,” says John Sipher, a former US intelligence officer who served 28 years within the CIA’s Nationwide Clandestine Service. “This isn’t all the time attainable in individual attributable to political constraints or battle. That is the place quantity stations are available in.”
Whereas using quantity stations will be traced again to the First World Conflict, they gained prominence throughout the US-Soviet Chilly Conflict. As espionage grew extra subtle, governments used automated voice transmissions of coded numbers to speak with brokers, Goldmanis says. Citing declassified KGB and CIA paperwork, he provides that quantity stations have been extensively used throughout this era, typically as Morse code transmissions and, in lots of instances, as two-way communications, with brokers reporting again utilizing their very own shortwave transmitters.
“These days, you may have numerous satellite tv for pc and encrypted communications applied sciences,” Sipher says. “However throughout the Chilly Conflict and even earlier than that, governments needed to discover methods to do that with out being observed, and broadcasting coded messages was one solution to talk together with your belongings discreetly.”
The obvious randomness of the numbers means they are often understood solely with a codebook, Sipher provides. “No person could make heads or tails of it or perceive what it says except you may have the codebook that may give you hints to decrypt the code,” he says, noting that such techniques have to be arrange and coordinated upfront.
A Sign With out a Sender
Whereas the probably origin of the sign could now be clearer, its goal and meant recipient stay unknown.
As a result of the broadcasts are encrypted and designed to be covert, these particulars could stay unclear for years, Goldmanis says. The structured nature of the transmission—its mounted schedule and constant use of frequencies—additional suggests it’s a part of a deliberate operation.
