In understand that the stock antennae on most HT's provide minimal performance. For the Kenwood TH-F6A, (receives 0.1 through 1300MHz), what antenna or antennae would produce significant improvement below 100MHz short of going to an outdoor antenna? I will have a dual band attic mounted J-pole for 2 meter/70cm. Are there any recommended radio-mount antennae that would result in significant improvement over the stock rubber ducky? Anyone with experience with in-room mounted (semi-)long wire for receive only? Other options, e.g. in-room long wire with antannae amplifier?