Hi to All, I'm new member and this is my first post, I built Delta Pulse 2S with coils 19 cm, enameled copper wire of 0.4 mm (I just have one role of it) with 31 tourna. So, my questions are: 1. How can I make my DPA 2 metal detector sensitive to IRON with small pieces? 2. What is the best frequency to detect small targets with iron? 3. What parts of the PCB must be changed to be able for detecting even small iron pieces? 4- any advice for coil? and what is the best dimensions of coil? I'm looking for you answers and advices, Thanks