Although the SAO RAS hasn't said what sort of analysis led to the researchers to their terrestrial conclusion, today's announcement does note that the RATAN–600 covers a wide range of frequencies from 1–22.7 GHz, which allows it to search for extremely weak signals. The "interesting" signal had a wavelength of 2.7 cm, but the SETI team only managed to pick it up once out of 39 tries. In an attempt to confirm the signal, the Allen Telescope Array in California was also pointed in the direction of the star system HD164595 in late August, but has so far failed to pick it up.
This wouldn't be the first example of a false alarm: In the past, mysterious signals picked up by the Parkes Observatory in Australia were actually attributed to microwave ovens opened by hungry astronomers who couldn't wait for their food to be ready. While the Russian team still hasn't identified the signal's exact source, the speculation is that it was a "parasite" signal coming from a plane or other satellite. For now, the SAO RAS concludes, "It can be said with confidence that no sought-for signal has been detected yet."