from KurzweilAI:

On May 15, 2015, Russian astronomers picked up a radio signal on the RATAN-600 radio telescope in Russia “in the direction of HD164595,” an international group of astronomers stated in a document* now being circulated through contact person Alexander Panov, according to Paul Gilster of Centauri Dreams, who blogged about the data on Saturday, August 27, 2016…

Power required for such a signal would be astronomical, he explains. If broadcast in all directions, the required power is 10²⁰ watts (100 billion billion watts) — hundreds of times more energy than all the sunlight falling on Earth. If aimed at us, assuming an antenna the size of the 1000-foot Arecibo instrument, they would still need to transmit more than a trillion watts.

In addition, the signal was received at 11Ghz (2.7 cm wavelength), in a part of the radio spectrum used by the military, so the signal may be due to terrestrial radio-frequency interference, or to gravitational lensing from a more distant source.