9x12 coil pinpointing, need advice

[blaglezz]

Hello; I've never used a 9x12 search coil on the Ace 250; I tried it today for first time and was having a real hard time pinpointing. Can you give me some advice on how to pinpoint with this coil?

Another thing...I've got a couple of very nice coin signals, supposed to be deep coins, but after digging for a while the signals completely disappeared. Is this normal? If so...what is the reason for this?

Thanks!

 

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[relicswinger]

The 9X12 is great for a lot of things, there are a few things to know about it however:
1. When you are pinpointing, get the target under the center and pull it backwards until the sound begins to fade. For me the target is under the "G".

2. If there are two targets spaced apart the same distance as the width of the coil you will get a false positive that will have you digging to China thinking you must have found a very large, very deep target. If you are digging deep and not finding, use the smaller coil to check around the perimeter of the hole, or you can scan around the perimeter with the front of the coil by walking around the hole.
3. A large hunk of metal may "edge pinpoint". This is when instead of being under the center of the coil it is under one side or the other. This will give three beeps. One under the left edge, one under the center and on under the right edge.

4. Sometimes I lose the target and have to reacquire the signal. Not sure why...

 

[blaglezz]

Hi, relicswinger...thanks for your response...but what do you mean when you say "under the G"?

 

[relicswinger]

My 9X12 has a sticker on it that is "Garrett". It is the "G" in Garrett...

 

[blaglezz]

Mine has an sticker rather to the right, is that the one?

 

[relicswinger]

My sticker goes from front to back on the central spine. The "G" is near the top as I'm using it.

 

[blaglezz]

Relicswinger, I appreciate your help. My coil has an small sticker on the right side. Can you tell me approximately the position on your 9x12 that this point is?

Thanks!

 

[relicswinger]

The sweet spot on my 9X12 is 2.5 inches behind the front edge, it might not be in the same spot for you. The best way to find where your coil's spot is, is to do an experiment. Find a place in your yard where there is not any metal (it can confuse the results of the experiment). Put a dime on the ground and faux locate it, swinging side to side as usual. When you "know" where it is, place the central spine over the target and start dragging the coil back until the tone starts to fall off. This is where your coil's sweet spot is. Put a sticker on that spot for future reference.

 

[Shortstack]

The sweet spot on my 9X12 is 2.5 inches behind the front edge, it might not be in the same spot for you. The best way to find where your coil's spot is, is to do an experiment. Find a place in your yard where there is not any metal (it can confuse the results of the experiment). Put a dime on the ground and faux locate it, swinging side to side as usual. When you "know" where it is, place the central spine over the target and start dragging the coil back until the tone starts to fall off. This is where your coil's sweet spot is. Put a sticker on that spot for future reference.

Exactly right. Each machine has it's own quirks you need to discover. Do as relicswinger suggested, but mark the top of the coil with a line of white paint. Place the marks to represent the outside ends of a set of crosshairs. Some folks even take small diameter straight rods of plastic and hot glue two pieces at right angle to each other to form a full crosshair over the target.