Dunno if they still operate this way but there's an east coast, midwest, and left coast tacamo orbit. They fly tight circles to keep the trailing wire antenna as vertical as possible so it has a better chance of being heard by our subs.
Haven't read the article yet but Russia has an almost identical mission, flying tight loops to keep subs in contact with hq. They use a fleet of 6 Beriev Tu-142MR Bear-J, modified Tu-95 Bear bombers. So if you're ever getting a sig at 18.1kHz and the source keeps moving according to your loop antenna, you might be tuned to a Tu-142MR doing russkii tacamoskii.