CONTENTS
28 
Target Trace (Continued)
Bottle caps
Bottle caps, complex targets and highly variable junk targets that have a combination of ferrous properties and conductive 
properties very similar to coins generally appear in the bottom half of the map. The Preset Lower Limits settings in 
Ferrous Limits (page 47) are designed to capture this area of the ID Map to assist in classifying bottle caps as ferrous.
If you repeatedly find the same type of bottle cap, choose a different Ferrous Limits Preset, or edit the Ferrous Limits to 
cover the Target Trace. In general, a higher-numbered Preset Lower Limits setting will be more effective at classifying 
most bottle caps as ferrous. 
Detection of a common brand beer 
bottle cap (bottle cap A), detected 
parallel to the Coil.
The Lower Ferrous Limits edited to 
cover the Trace and mask out the 
bottle cap.
These Target Trace examples show the variation that is possible for a single bottle cap.
A different bottle cap (bottle cap B), 
showing a different shaped Trace to 
bottle cap A — bottle caps are highly 
variable in composition, making 
them difficult to discriminate.
Bottle cap B is more difficult to 
reject as iron, and requires a higher 
Ferrous Limit Lower preset setting. 
Bottle cap B laid at a 45 degree 
angle. In this case the detector is 
seeing both the flat shape of the 
object, and the narrower sides of the 
object, which tends to appear in the 
upper ferrous region.
Bottle cap B laid on edge (vertical). 
In this case the detector sees very 
little of the flat shape of the object, 
and the response lies in the upper 
ferrous region.
Nails
Nails are highly ferrous objects that generally appear in 
the top half of the ID Map, and can be easily managed by 
adjusting the Upper Ferrous Limits.
Detection of a nail. The Upper Ferrous Limits edited to 
capture the Trace.
Ground signal
The ground signal often appears at the very top of the ID Map around ID 35. The exact 
shape and position varies depending on the ground conditions.