The frequency is similar to those which are typically being used for that kind of task (Germany has shut down one of the biggest time sync radio station recentl

The frequency is similar to those which are typically being used for that kind of task (Germany has shut down one of the biggest time sync radio station recently). For me it seems like a test for a wave pass, I mean if you want to send a message to some submarine via radio wave but have some hesitation whether the message reach the receiver, no callbacks are allowed for obvious reasons.