BDiNOU
RAG - Range Azimuth Gating (if I recall correctly) - a system whereby known areas (boxed areas on the radar display) of PE could be tweaked using less gain etc depending on the prevailing atmospheric conditions (i.e. propogation)... it was a system of several different hard settings that could be selected; was pretty effective at reducing clutter in areas where PEs where known to occur, but was used judiciously so as not to totally knock everything out. Somedays it was used, other days not, depending on the eatmospherics.
4 or 5 different settings available so the user could select appropriatly. No doubt it could still be used at the radar source, before all the processing that occurs today; it's whether the powers that be would say it was worth it, and whether the engineers thought it was truly feasible.
Above is a very distant memory of the RAG maps, from a long time ago, but hopefully explains (somewhat poorly) what they were about