Hi all and Happy new year Many members knows few years ago i build a clone Alonso-PD This old "amateur clone" i use many-many mods for find the best balance between all stage. But is not enough for me. Last months i start again experiments. My "target is... I try work with the same method use by Alonso for calibration omega-coils and feritte all together with standard schematic publish here from qiaozhi without any extras. I find this method and i build a "real alonso-PD clone" with all parts. My prototype now can detect a very-very small magnet-piece 2 meters distance very easy and a micro transmitter 433MHZ more than 50 meters distance. My clone has not false signals from South-north magnetics lines and with calibration knob i can calibrate machine very easy in search-area In my test-area work perfect, but i need make tests with unknown area and ofcourse video's with unknown targets This knob for calibration and very small mods (low-bat section, power supply section) are the only extra's The truth is that the calibration is too difficult and now i understand why there were failures to construct a truly clone Here some pics my prototype Heltkit section and feritte section work together without extra selection switch. Output signal from feritte coils is very-very low and feritte section now, work without overload signal. Next days if i have free time i publish here more infos and i start video's with prototype I want to thank a forum member here ( very good electronic engeneer ) , because, with his help and testing , I managed to find all the problems encountered best regards