As you know, i am not dowser, in this case i have not opinions. About OBMD-3 attachment photo. This is IR lens for Gold sensor, was made design and manufactured by me. This Fernel lens work in very critical resonate IR fasma and one video
https://www.youtube.com/watch?v=j951...ature=youtu.be, experiments this lens with light and placing back panel OBMD-3.
About PD only for Gold, after study very well all results, be sure 100% working. Need only free time for final tests
best regards