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"Search coil to ground ... come in ground."

June 26, 2018 05:03PM avatar
Yes, the ground. We take out detectors out to find good stuff. Things that interest us and we certainly want the best performance we can achieve. We use the proper Discrimination to deal with trash targets. Set the Sensitivity high enough to get us better depth and small-target detection. Select a search coil to provide the performance needed for the site we are hunting. Make sure we have a proper and functional Threshold level for a search mode that is Threshold-based. We might select a Tone ID function that we are comfortable with. And we are encouraged to set a proper Ground Balance, if a particular make or model or search mode provides such adjustment.

Folks do what they can to deal with grass and brush, and handle the ground balance setting ... but many, most probably, do not do what they should do to deal with a ground mineral signal. Some makes or models might produce an audible 'overload' audio or display response if there is overloading, call it saturation, if you will, of the EMF. That's an alert to raise the search coil away from the offending source. Some models don't do anything if the search coil is too close to the cause of the overload and they just remain silent .... very silent!

This can come from working a search coil too close to a metal object, perhaps too close to a specific hot rock, and all too often the overall performance of a metal detector is negatively influenced because the coil is worked too close to the ground , and that means the ground mineral signal is impacting the field that is too close to the search coil. That can warp the EMF and cause an overload reaction, or it can simply have a negative effect on the total search field and warp it such that it is misshaped and, quite possibly, not providing the ultimate performance in depth-of-detection.


Quote
Dan'o
That 2" + or - is difficult for me on grass. I find myself skimming the top too much.
Usually a Coin Hunter, working any grassy lawn can efficiently "skim the coil" along the top of the grass without a problem. The grass height is most probably ±2" above the dirt level. Actually it can be even higher depending upon the lawn care (mowing) at a site.

Where many make an error is when hunting fields, beaches, or any other site that has no barrier between the dirt and the search coil, and they get in a bad habit of "scrubbing the dirt" .. or rocks, pea gravel, sand or other mineral body. For decades I have pointed this out to people when we have been out detecting and I see such incorrect behavior. They usually say they want to get better depth, but what they are not aware of is that having the coil too close to the ground actually can impair the detector's performance.

Read almost any detector manufacturer's Owner Manual and you we find that they generally state to keep the coil off the ground. Use it at about 1", maybe they say 2", and often it is just a ±2" coil height. A few years ago I read one manual that said an operator ought to keep a coil 2" to 3" off the ground, but I find a ±2" measurement to be very functional. The best coil position will be in the give-or-take range of measure.

Monte

"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells
Trading Post

Metal Detector Evaluations and Product Reviews
'How-To' help for Coin & Jewelry Hunting, Relic Hunting and Useful Techniques.

'Regular-Use Detector Team' are models from: Fisher, Nokta / Makro, Teknetics, Tesoro and White's
'Specialty-Use Detectors' are models from: Compass, Garrett and Teknetics
Pinpointers: Using Nokta / Makro and Uniprobe Pointers.
Headphones: Using Killer B's 'Hornet' and White's Pro Star and Detector Pro's Uniprobe ... All w/'tank style' ear cups.
Recovery Gear: Using White's DigMaster digging tool and Signature Series pouch.
Note: Detectors are listed alphabetically by Brand. Models are chosen as desired based on search site conditions.
Some models are assigned for 'Regular-Use' and others are on-hand for 'Specialty Use.'
Additional search coils, mounted on spare lower-rods, are on-hand in my Accessory Coil Tote.


*** All working well today to make memories for tomorrow. ***

monte@stinkwaterwells.com .. or .. monte@ahrps.org
(503) 481-8147
Subject Author Views Posted

New to me Impact

Dan'o 211 June 25, 2018 09:25PM

Dan'o, here are a few thoughts and observations.

Monte 146 June 26, 2018 01:31PM

Re: Dan'o, here are a few thoughts and observations.

Dan'o 119 June 26, 2018 03:55PM

"Search coil to ground ... come in ground."

Monte 115 June 26, 2018 05:03PM

Re: New to me Impact

Dan'o 127 June 26, 2018 07:45AM



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