Related Clues:

• Echo sounder
• Early sonar, to Brits
• Now the son gets a R these days like five hundred, I see, used to be
• A disc as sonar used to be
• British term for sonar
• Device that sounded deeply involved in position-finding
• It once sounded like Little Richard, we're told
• Early echo-sounder; a disc (anag.)
• Early form of sonar
• It sounds like the beginning of dictation
• Like detectives turning up old detection method
• Detector used once since detective docked
• An early form of sonar, an echo sounder
• Sonar, formerly a way of detecting low tars?
• Like detectives going back for a detecting device