The US Navy still uses VLF, though ELF comms seem to be retired at this point. https://en.wikipedia.org/wiki/Communication_with_submarines#Very_low_frequency h

The US Navy still uses VLF, though ELF comms seem to be retired at this point. https://en.wikipedia.org/wiki/Communication_with_submarines#Very_low_frequency https://en.wikipedia.org/wiki/Communication_with_submarines#...