Horrifying throbbing low-frequency rumble:
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Low-frequency rumble, high-frequency squeak
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Geiger counter
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Horrifying throbbing low-frequency rumble
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High frequency pulsating electronic signal
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Interference Broadcasting
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Morse code transmission
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Reception, Morse code, transfer
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Morse code, welcome
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Radar, location alert
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Radio Setup
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High frequency squeak
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Brown noise
★★★★★