I suspect many here already have a solution on their shelves, even if they are not already aware. The popular Tecsun AN-200 loop can work as an inductive MW coupler. Just connect the whatever external antenna feedline to the AN-200 1/8"-jack antenna port. IIRC, even with my old 148' loop-on-ground connected, the AN-200 still had some circuit Q to further help peak the tune.