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Voice communications via acoustic means has been around since World War 2. Look for the UQC systems. They used single sideband modulation. VLF broadcasts hav
by rbc 17y ago
Voice communications via acoustic means has been around since World War 2. Look for the UQC systems. They used single sideband modulation. VLF broadcasts have been around for a long time as well. During the 90's, I'd walk into radio on the USS Cavalla to go on watch and we almost always had the VLF fleet broadcast coming in on the teletype printers.