Morse code, SOS signal reception:
-
White noise
-
Low frequency electronic signal
-
Brown noise
-
Interference Broadcasting
-
High frequency signal
-
SOS signal transmission, Morse code
-
Radar, location alert
-
Morse code, transfer, reception
-
Low frequency pulsing and humming signal
-
Geiger counter
-
Energy buildup, Electronic signal
-
Horrifying throbbing low-frequency rumble
★★★★★