Hi Schmidt1989… your detector should not produce signals while the coil is raised in the air. Possible exceptions might include EMI generated from passing planes or traffic, or from industrial / residential electrical interference. Residential EMI is more pronounced during the summer months because air conditioners and pools are operating. It can make a real difference if searching residential parks. So ensure the coil connection is secure, and take
smokeythecat’s excellent advice if this is an ongoing issue in areas that should be reasonably free of EMI sources.
In addition to the excellent comments above, let’s discuss ghost signals that are commonplace in the field, because normally there is a good explanation as to why such signals are produced. Let’s look at a few examples that most of us have experienced at one time or another.
A common scenario is a signal produced by disseminated / mineralized iron remaining
from iron junk that has rusted away in the ground. Rust is a form of maghemite, a powerful magnetic susceptible iron oxide that registers about mid-range on a typical ground balance scale. That is well below where your detector’s fixed ground balance is preset, and therefore it will produce such signals. When you dig and disturb the rust deposit, it will not likely be able to respond any further with an audio signal… hence we consider it to be a ghost signal.
A discriminated target occasionally signals in the dirt, but many will not respond once the
soil has been disturbed by digging, and / or the target has been brought to the surface. I don’t
know if this type of scenario applies to your detector because I’m not familiar with it. But I imagine it does. Keep in mind too that sometimes a small target falls deeper into the hole such that it can no longer be detected. A few more scoops will usually bring a target to the surface, but scan the hole with a pinpointer to be sure.
We occasionally see similar results using PI units while prospecting for Ontario silver. A
perfectly good signal is dug and voila… no signal anywhere. Usually associated with sponge or disseminated or even with weak leaf silver, once out of the dirt it will simply not respond to the PI electromagnetic field. In all cases to date, a VLF motion all-metal mode has quickly located such targets in the dirt pile. Although this doesn’t apply to your circumstances, you might as well know about it.
We sometimes encounter signals generated by ground anomalies that differ both in type and
strength of mineralizations from the general terrain. Examples include former campfire sites producing a positive hotrock effect even if actual rocks are not present, electrically conductive animal urination spots, or other relatively conductive spots usually related to the occurrence of various (fertilizer for example) mineral salts. Sometimes an abrupt physical change to the soil type such as a small clay deposit with differing moisture, electrical and magnetic characteristics can produce a signal. But digging disrupts the electrical continuity or magnetic fraction such that it can no longer produce a signal, and it becomes apparent there is no metal target. Thus we describe it as a ghost signal.
Hotrocks are a separate issue that I wouldn’t characterize as ghost signals. They are very real and identifiable signals produced by rocks. If you would like to learn more about the subject, click on the following link and scroll down to the hotrock section.
http://www.treasurenet.com/forums/c...-magnetic-susceptibility-february-2011-a.html
The bottom line is that your detector operates with a fixed ground balance and therefore your options are more limited. Learn to identify the hotrock types that occur in your area. Where hotrocks are plentiful such that they’re a real distraction, use sufficient discrimination to eliminate their signals.
Jim.
