There are several possible reasons that noisy data can occur. See below for common sources.
1. Earth Interface:
Cables and the electrode stake to earth interface are the primary source of data noise.
2. Ground Loops
Batteries can also ground to earth partially by sitting directly on the earth.
3. Improper Power:
Another source of data noise is improper power. This can be from low voltage battery (<12V), other devices connected to the battery such as chargers.
4. Cable wear and tear:
Cables are susceptible to wear and tear as well as connector contamination. Leaving cables unattended and especially overnight will guarantee animal chew--which are hard to spot but will give moisture a pathway through the protective outer jacket.
ERI systems use high voltage electricity—and with the passive cable design, both high voltage transmitting wires and low signal receiver wires are in close proximity of each other, so controlling electrical leakage is of paramount importance. This means regular inspection of the connectors for any dirt or moisture is recommended.
The Dual-Mode cables with internal switching electronics do not have this issue due to a patented design of the cable. It is always best to keep the end caps on the cable connectors closed when not connected and to hand coil the cables. Never drag or pull resistivity cables on the ground.