MFJ 931-Artificial Ground
The solution for insufficient grounding in the shack.
Transforms the present system into a nearly perfect ground system. Even if no grounding at all is available you can just lay out a wire. Useful against BCI/TVI or with 'hot' chassis. Useful when your shack has a very long connection to a ground system.
The MFJ-931 is installed between your rig and a ground feed and tuned to maximum ground current on the operating frequency. Frequency range 1.8 to 30MHz, dimensions 18 x 18 x 8cm.