It's not uncommon for hams to hear themselves a second or two after they transmit on HF as their signal propagates around the world and then comes back on the "backside" of their antenna. It's even been reported that hams have heard their own voice come back 2, even 3 times.
But one ham in Germany recorded hearing his own CW transmissions an astonishing 46 seconds after sending them!
Peter Brogl, DK6NP, experienced this rare and little-known phenomenon (known as long-delay echo, or "LDE") on Nov. 27 on 7 MHz and managed to record the echoes.
The reasons for LDE's are unknown, although many theories exist as to their cause.