Hi all,

I was just trying to figure out how accurate air testing really is when it comes to the real world. I would think that it's just an indicator of potential depth the machine could reach. I was thinking of this as I was watching some videos comparing different models of detectors and different coils. For example, one of the coils I am buying air tested a large cent size copper an incredible 20-22 inches! The same setup tested a quarter size coin 18-20 inches. The same machine with the Minelabs 10.5" DD coil tested the same coins far less than that. On the other hand, a CTX 3030 and E-Trak were tested with the stock coil in another video and both maxed out at barely 12" using a quarter, gold rings, silver, etc.

I also guess this opens the door to another question. What is the real advantage of the FBS machines over a single frequency machine that is set up correctly and has almost twice the depth capability? I know the FBS machines can even the field in depth between different metals such as gold or silver being at opposite ends of the conductivity spectrum. But, I would think the single frequency machine would detect more in the long run due to it's greater depth capability as it would give stronger signals on a target at depth over the FBS machines that are at the end of their range.