Here is a NDB ADF long wire antenna which I use on HF. There might be an inline loading coil at the base of the antenna, if so you simply remove and hook the RG58 directly to it. I use a remote antenna tuner as close as possible at that point. Nothing's installed permanently on the airframe or panel, the antennas are already on the airplane or installed properly as required by the FAA and are approved aircraft antennas. The best thing if you're renting aircraft is to use a tape on the inside window wire antenna. Keep it as far away from you and passengers, remember RF exposure safety. But you're probably only using a hand-held and push-to-talk Transmissions which are short. Remember using any unapproved transmitter in the aircraft in instrument conditions may not be approved, and interfere with on board instrumentation and your safety.