Relying on electromagnetic fields means EM-1 signals easily pass through the surface of water instead of scattering like sound and light waves. In fact, devices signaling with cable-free, highly resilient RadiEM also transmit reliably through the water column, seabed and subsea structures. Paired EM-1 modems can be mounted on piles, buoys, nets, or pontoons above, on or below the water and do not require line of site placement.

Transmission from Sensor to Shore

Ideal for deployments and applications in the splash zone and shallow water environments, where adverse conditions may exist, the EM-1 is designed to pair with underwater sensing systems, enabling cable-free connections from below water to topside EM-1s paired above the waterline. Compatible with sensing systems such as multiparameter sondes and ADCPs, EM-1 modems use industry standard data interfaces like RS-232.

EM-1 Value Over Existing Solutions

As the first and only reliable cable-free data transmission through the surface of water, EM-1’s using RadiEM unlock flexible placement and movement of underwater digital devices in and between more locations.

  • Cables often become snagged and fail due to repeated stresses from wave motion
  • Acoustic signals bounce off the surface and are degraded in turbid or choppy water
  • Optical solutions scatter signals at the surface while underwater they require line of site, are effected by biofouling and are degraded by ambient light and turbidity


  • RadiEM performance is unaffected by biofouling, turbidity or environmental noise in the water column and does not require line of sight
  • RadiEM is totally invisible and totally silent, so there are no adverse effects on aquatic life or use in security systems
  • Bidirectional point-to-point communication is available today; multi-point connectivity and relay capability planned for the future