In an inductive telemetry system, what is the maximum recommended resistance of the mooring wire and seawater return path that would allow communications to function properly?
We do not specify a maximum line resistance. However, the Inductive Modem systems are very tolerant of the resistivity of seawater. It is typically only a consideration when the system is being deployed in freshwater lakes, etc. where the salinity level is a lot lower.
We recommended using one of the two oceanographic cables below or those of equivalent specification:
1. Loos & Co. 3×19 Galvanized Oceanographic Cable, Plastic Impregnated
2. WireCo WorldGroup Macwhyte 3×19 Space-Lay Plastic Impregnated and Coated Wire Rope
The most important aspect is the resilience of the cable jacket. Any cuts, tears, or breaks in the insulation will create a shorter path to the seawater ground which will result in the the level of the signal on the lower side of the cable being attenuated.