Submarine Communication

The video discusses the challenges of communicating with submarines underwater due to the ocean's salt concentration affecting radio waves. It explains that while radio waves used on land are ineffective underwater, very low frequency (VLF) and extremely low frequency (ELF) radio waves are used for submarine communication. VLF waves can penetrate up to 20 meters underwater, allowing communication when submarines are near the surface. For greater depths, ELF waves are used, which have very long wavelengths but require large transmitters, making them suitable only for one-way communication from base to submarine. Due to their low frequency, ELF waves carry limited information, often just a command to surface.

How do the wavelengths of ELF radio waves affect the size of transmitters needed?

What limitations do submarines face when using ELF communication?