Originally Posted by
Sikpilot
The technology already exists and is being used. My cousin said he routinely sends devices 6000 meters down in oceans and they will answer him back only after he transmits to them. The batteries last over a year.
That's all great and well if you know where to look. It also adds the requirement for equipment on board of a ship/land that can transmit a (powerful) pulse on yet another frequency, rather than just listening with any device.
What we really need is longer lasting batteries AND a stronger pulse. The arbitrary spec requirement from the past has well and truly been proven inadequate. Fix it!