Multi-fixed-station AM receiver
Try a vertical whip.

Have 3 high-Q PI matching networks; these frequencies are not harmonically related, thus high-Q networks will minimally interact even tho fed by the same (whip) antenna. Let the whip be quarterwave at 3.33 MHz, and craft the high-Q networks at 7.85 and 14.67 to handle long-wire vertical-wire antennas.

Feed the outputs of the 3 high-Q networks into your choice of LNAs.