This circuit found in Electronics Handbook, Volume XIII 1993 shows a simple configuration of a tuner for MW stations. The signals are applied to the input of any good audio amplifier. The coil consists of 100 turns of 30 AWG wire 28 and a plastic tube of 1 inch or broom handle and variable may be taken from a valved AM radio discarded. The antenna should be long (over 5 meters) and the ground connection is important. Any germanium diode can be used in this circuit and even a galena crystal.
