ground vs. counterpoise
Although used inappropriately as such, a Dynaplate cannot provide an effective counterpoise. The distinction between DC and RF grounding, in this context, is that the Dynaplate will not provide an effective RF counterpoise (RF grounding) which is what it sounds like you are asking about. Although not a good explanation, the counterpoise, which is what determines the efficacy of an antenna, needs to be sufficiently broad enough to act as a RF reflector of sort. The best counterpoise will exhibit the following characteristics: copper foil continuously run from the tuner chassis throughout the hull, common connections to underwater matals such as thru-hulls and/or keel bolts, connected to the mast and rigging so as to preclude interaction with the antenna and not connected to DC noise generating electrical devices. Depending on the boat mfg,this becomes problemmatic since some mfgs bond everything to the engine as DC grounding, including the goodies that generate noise like altenrators, inverters and refrig compressors. There are too many variables to suggest one single best method and you might be better off to read up on effective counterpoise systems in some of the various marine how-to books. Some people don't bother to install one and claim their HF radio works well.
