Peace be upon you and Greetings to all my brothers i have just finished to build Delta Plus but did not work well, the problem is that detect metals no more than 15 cm, whatever the size I tried to set it but to no avail .please i need your help to solve this problem . Thank you in advance.Peace be upon you and Greetings to all my brothers i have just finished to build Delta Plus but did not work well, the problem is that detect metals no more than 15 cm, whatever the size I tried to set it but to no avail .please i need your help to solve this problem . Thank you in advance