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Pinpointing Inaccuracy Theory


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Since working with the Eqx I've suffered occasionally with poor pinpointing.  I've also seen posts from others having the same problem.  There are some obvious explanations:

1) poor pinpointing technique;

2) nearby targets pulling the pinpoint location to the wrong place;

3) ??

Since it continues to happen to me, even trying to compensating for #1 and #2 above, I've come up with another contender:  non-horizontal target orientation.  E.g. vertical.

This is something a test setup/garden might be able to determine but I don't yet have one of those.  Non-horizontal target orientation may be a rare situation.  Yesterday discussing this with an experienced (coin) detectorist I was told that it is extremely rare in his view.  Still, I have trouble figuring out why, even with careful technique, I often miss a target location by several inches.  Anyone out there want to express his/her opinions?

 

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Non-horizontal targets are NOT "extremely rare."  And yes, a target tilted vertically will throw off pinpoint, for sure.  It's pretty common to be off by several inches when detecting an "on-edge" coin.

Steve

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It's embarrassing to admit, but my pinpointing with the Nox 800 is not as good as me with the explorer's. Hopefully I'll get better at it..pinpointing has not been a problem the last 25 years ? I just seem to be an inch or two off at times..strange!

 

HH

Sillllvar

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  • The title was changed to Pinpointing Inaccuracy Theory

My experience with my 800 is that the built in pinpointer is deadly accurate for most coin targets.  If I get a questionable response I'll visually mark the target area (based on peak sound) then rotate 90 degrees and find the center again.  Sometimes dragging the coil across the target area with the coil tight to the ground will help with peaking the sound response.  Having the coil as tight to the ground as possible is a must.  If you use the wiggle method for pinpointing, tighten up the wiggle as you zero in on the target.

My peeve with the EQX pinpointer is the inconsistent audio when activated and the need to turn the pinpointer off then back on again to get robust audio.  Sometimes lifting the coil (you should always lift the coil) and waiting a few seconds before turning the pinpoint function on helps with getting the normal pinpoint audio instead of the weak audio.  I hope Minelab fixes this occasional weak pinpoint audio with a firmware update.

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I've done some more thinking on this.  I do really like the pinpoint feature of the Eqx, but it's not perfect, IMO.  I'm not complaining.  Facts (or at least claims) shouldn't be interpreted as complaints.  There isn't a perfect detector and there never will be.  Bottom line is that it helps to know the limitations.

I've frequently had the pinpoint pull me away from the target I've been trying to find.  Pretty sure that is because another target in range of the coil is stronger (in the 'eyes' of the pinpoint circuit and software) and it 'pulls' me to that.  Other than changing the coil (or maybe turning down the gain), I don't know any way around this.  As such I sometimes have to use other pinpoint methods.  In trashy areas (almost everywhere I hunt), the 90 degree technique has problems as well, because the strength of the signal coming from the coil isn't symmetric.  In my experience, the toe is less likely to see a target off the coil than the sides of the coil.  This can be experienced when near a chain link fence -- you can get closer to the fence without detecting it by facing the fence head on as opposed to swinging (left/right) into and away from the fence.

The wiggle method is where I think I have the problems getting a false target location.  Actually, Mark's video:

may be a hint that my theory has veracity.  Right under the center of the coil is where a vertical coin gets silent.

I'm never 100% sure of anything so I may be misinterpeting what I'm experiencing.  But I've never had this kind of issue before, where I pinpoint and subsequentyly find the target well away from that spot.  Most of the time the wiggle method gets me spot on, but it fails enough that I don't think it's just me being sloppy.

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Iffy signal i agree i am extremely happy with the pinpointing on my equinox, ive actually been able to reduce the size of my plugs considerably.

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It's probably always going to be a challenge to pinpoint when good targets and trash signals are tight together.  If you know the typical trash ID numbers (like 14 through 18 when you are coin shooting) try eliminating them in Settings to focus on the known good target IDs then re-scan the area before trying to pinpoint again.  This may get you in the ballpark.  I still like the 90 degree double check in these stituations.

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2 hours ago, kiwijw said:

Why would that be? I find the Zed shocking for pinpointing. Interesting topic. Thanks

Good luck out there

JW :smile: 

I can't explain the technical "why" of it; my assumption is that it has to do with the orientation of the EM field associated with the induced eddy currents in a tilted target (relative to the receive coil) versus horizontal one (relative to the coil).  I can't explain the "why" of it, only that it's something that I commonly have observed over the years, with several different detectors...

Steve

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Don't know if anyone else has noticed that:

Solid targets like coins and pull tabs are usually bang on with pinpointer.

Targets like folded foil or ketchup packets can be up to three inches off center.

Have not noticed other targets pulling pinpointer off target.  I always sweep over target area after replacing plug.  Coin spills taught me to always recheck!

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