1971 Dodge Dart Radio Antenna

Hello Mopar Brothers and Sisters. I have a 71 Dart that had no radio when I bought the car. I was able to locate an am/fm radio for an A body (71’ Dart was am only). The previous owner removed the radio and CUT off the antenna wire FRaaaaaak. I am aware that there is an aftermarket fm booster antenna available but it mounts on your dash or windshield. I don’t want the antenna exposed. Does anyone have any experience with these units (hidden under the dash), or do I go shopping for a replacement antenna. Cheers Ron D