Hams might be the only communication. dit-dit-dit dah-dah-dah, etc.
When we quit hearing dah-di-dah-dit dah-dah-di-dah, and instead hear, di-di-dit dah-dah-dah di-di-dit on 20 meters, then we know we're in real trouble. ;-)
dah-dah-di-di-dit di-di-dit-dah-dah dah-di-dit dit dah-di-dah dah-di-dah-dit dah-dah-dah-di-dit dah-di-dit dah-dah-di-dah di-di-di-dit