I built two radios. I followed a builder of these who posted a video. I used the Germanium diode and the proper resistor for Crystal radios. I also built an antenna. The radio in the photo used 19 gauge magnet wire for the main coil, 127 turns. I used the ground in the wall socket for ground with a plug that had the nuteral and line cut off. For an antennat before I built this one I had an 8 gauge wire 16 feet long with the two ends soldered in a loop. I put on two clamps on the ends to make it so the solder would not break. I strung it up outside with bailing twin made of a plastic so it surved as an insoluator on both ends and then hooked it to two parts of the house to make a horizontal line about 9 feet above the ground. I then used an aligator clamp on the ground and antenna to hook to. I also know about magnet wire and cleaned all ends that needed to make contact. I also used a Ohms meter to to check to make sure all the circuit was making the connections.
Once built, I could get nothing but some buzzing and a pop now and again. I went over it several times and posted a link to the builder I copied. He said it was correct. I happened to run across a video on the piezoelectric earphone. The video was from a experienced builder who said he orders in bulk for Boy Scout projects. Out of 100 of the Taiwan made earphones 33 were not working. He cut one of the bad ones apart. He found that the second contact was glued in and they glued in the plastic earpiece to the other half. They messed up the glue as it got to the diaphragm and caused it to not work. He said he has never had any issues with the Japanese made earphones. I have one on order but I think this may be the issue. If anyone can take a look at my projects and let me know if they look OK. Thanks.