Renaissance Woman

The Components of Sonar and Their Development
The history of sonar is tied directly to the invention and advances that have been made in sonar over the decades.   The enhancement of the components of sonar equipment was needed to improve the function, usefulness, and accuracy dependent upon their many uses.   Military and civilian uses of sonar created new challenges and needs.   As in the case of many modern things, the inventions of war later became the gifts to mankind.   The history of sonar parallels the history of electronic invention.  
The original sonar type equipment, called passive sonar, was simply an underwater microphone or hydrophone.   Materials which would convert liquid conducted sound waves into electricity were created.   Vacuum tube amplifiers raised the signal to a level which could drive carbon based magnetic coil headsets for human listening and interpretation.
Components of Sonar
The original components then were the underwater microphone or hydrophone and emitter, cabling, signal amplification and listening device or visual display.   The microphones were limited in sensitivity secondary to early development of simply converting air based microphones to underwater use.   Original equipment lost a lot of signal at the source because of materials needed to create a watertight, military device.   After all, these were to be attached to the hull of a ship at sea.
The very small electrical signal was carried over wires over some distance from its underwater microphone to the amplifier, usually near the command center of the ship.   Microvolts or millivolts of signal were lost because of this wiring dilemma.   This limitation actually existed for two reasons.   First, it took time and experience with experimentation to realize the loss of signal and secondly, vacuum tube amplifiers limited the location of the equipment, which frequently needed repair.   Later, a “sound room” was created near the bottom of the ship for some of the electronic...