What are the Deep Search machines?

As the name says, they are made of two coils, one in front placed horizontal and the second is in the back placed vertical. Horizontal In the front is a receiver loop, and vertical in the back is the transmitter. In some units like Gemini III , loops may be located inside the electronics box, in some others, like as in TF-900 loops are outside the control box. These detectors work based on the concept of metallic objects blocking the radio wave generated by the loop in the back and received by the loop in front.

This group have a pulse inductive generating system that delivers an output through a wire loop of usually 1 meter by 1 meter (40 inches by 40 inches). They are sending a pulse signal through the loop and you walk in between holding the big square loop with two ropes. You hold the detector(control box) on your belt and walk slowly in between the loop.

pulse inductive units ignore salt and minerals very well. If soil contains minerals and salt, it sometimes creates false signals and cause depth reduction then you would need to use a pulse induction system to solve or reduce the problem.

How big the target?

Using a Deep search machine, whatever Two box or Pulse induction the target size must be at least as big as a soda can. They cannot detect a single coin. It must be a jar full of coins. You are here to know about deep search machines. VLF types with 8-9 inch coils are not Deep Search machines (Except Garrett CX Plus and GTI 2500 if depth multiplier is added). Deep search machines are for searching only BIG treasures and targets and they operate much much deeper than traditional vlf type detectors.

How Deep???

Based on many experiments, we have achieved the following depths for Deep search metal detectors.

TF-900 by Discovery . It goes about 3 feet for a soda can. 5 feet for a gallon size target 6-7 feet for an object as big as one meter cube and 20 feet for an automobile size object. But the Depth will not exceed 10 feet for an automobile in heavy salt environment. Most Finds with TF 900 are more valuable than other two-box units. In Greece and Ancient Golden Relic recovered about 4 feet. In Turkey 200 Gold Helenic (Greek) coins were recovered. In Mexico Gold Mexican Pesos recovered. In the Philippines several Japanese Gold bars buried by Japanese Army recovered. Overal working with TF-900 is easier than other Two-box machines because of Auto Ground Balance feature it has while other units do not have it.

Pulse Induction Machines: