>>4405159 (lb)
>No consensus on 17 second signal.
Agree no consensus.
I dug for several days on ELF/ULF frequency communications, which have been decommissioned.
Posted several times, bakers couldn't be bothered to share it.
In a nutshell, in 50s-80s US Navy used bedrock formations under the great lakes as an antenna relay for underwater comms.
Frequencies were higher than the 17-second/0.059 Hz signal.
Logical that tech advanced, possibly to those super low frequencies.
Q said something about blinding the DS caused tech not-ready-for-primetime to be activated.
Don't know if that wave was a comm signal, or to disrupt the comm signal.