A signal was spotted on 14th September 2025 in the early morning hours at 06:30 UTC. This digital signal was uniquely powerful and stood out in the spectrum, thinking it was either noise or a digital signal from nearby, it turned out to be originating from Russia after analyzing it's waveform. Upon analysis this signal was identified as "CIS-12".

CIS-12 is a PSK Russian military multi-channel modem, it is used for data communications over long distances without the need of a common communications medium such as the internet, this modem has the ability to send scrambled voice/data communication at the speeds of 4800bps.

A protocol called TDoA (Time Difference of Arrival) was used to find this signal. Time Difference of Arrival (TDoA) is a popular technique for geolocating the position of an RF signal—or more accurately, the position of its emitter. It uses the fact that all signals travel at the speed of light and relies on the signal being detected by multiple receivers.

An image demonstrating how a TDoA works

Over 400 TDoA scans were conducted on this digital signal and try to find what outcome is the most similiar, then investigate the areas around the most common findings. And this is what we got after attempting to triangulate this signal after a couple hours.