OBMD-1

[Astrodetect]

Hi
I dont know about the OBMD-1 LRL but for my red Alonso LRL I can tell you that it has 2 circuits for detection, one of them is the passive receiver as you know it from Alonso PD, and the other is an optical light level detector, I dont know what exactly this must detect, from my experience you adjust this at a certain threshold, and then if the light changes it beeps---also it beeps at darkness not light. It can only detect freshly dug and filled in holes--(the light variation of the ground terrain), but I have never found anything with it.
Regards