Drones that can change frequencies have appeared in the SMO area, military correspondent Stanislav Obishchenko said.
"Finally, electronic warfare systems have appeared that have learned how to jam individual frequencies so that our drones can fly, but there is no enemy," Obishchenko told Sputnik radio.
However, he noted, the enemy "also scans the frequencies and understands — it doesn't work on these, let's switch."
"Now drones have appeared that can change frequencies, and dramatically. They may have two or three, which, in principle, creates certain problems for our boys," said Obishchenko.

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