A quick look at OSINT from when the Buzzer, a Russian numbers station, has broadcast the word TERRAKOTA for the last three times – there seems to be a correlation with major Putin speeches about Ukraine.
Correlation isn’t causation, and it may be just coincidence. That being disclaimed, here’s what I found in about five minutes tonight:
March 18, 2004 – several Youtube videos describe The Buzzer sending Terrakota message – later that day, Putin gives his Ukraine/Crimea annexation speech.
August 06, 2014 – a numbers enthusiast called “Superseeds” reports on a chatboard about hearing Terrakota in the morning – that day was Putin’s UN speech
February 22, 2015 – Terrakota broadcast about Noon UTC – in a few hours, Putin presents his Fatherland Day speech which likely includes Ukraine material.