Erratic Air Test

[rwsnc]

Another question about an erratic xt70.

If I air test a dime and get 3" or more away from it, I get a 38 reading. If I get the coil down close, like within an inch or so, I start getting erratic readings that will go to 40, 42 and 46. When it reads 46, the depth arrows will show maximum depth and I'll hear 3 "beeps", when each of the 3 sets of wires (the left, middle and right parts of the coil) are over the coin. This happens with any of my DD coils. I tried sensitivity from 15 to 30.

Is this normal?

 

[BarnacleBill]

Yes with several factors.

1. You are overloading the detector.
2. There is no ground to work against.
3. The manual states that the coils should be swept one inch above the surface which helps prevent ground minerals from overloading the detector. Yes you may be able to work closer to the ground in certain soils, but there's always the case where you can't.
4. By their nature with an up close target a DD will report the rim, the surface of the coin, and the opposite rim.

Just for fun try a square tab with it's two holes lengthwise, especially with the 6 inch HF DD. You'll get a ratta-tat-tat as it picks up each perimeter.

HH
BarnacleBill

 

[rwsnc]

Thanks, Bill. I've been suspicious lately and you've put my mind to rest. That also tells me that if I start getting an erratic reading with 3 beeps, in close proximity, that I should raise the coil and sweep it again.

I've been struggling with the correct sensitivity setting.

I have a tough time disciplining myself to turn it down to 15 or even lower sometimes. I'll keep working with it. Thanks again.

 

[Gonehunting]

If I get a reading that sounds like you are describing. I usually pick up my coil(swinging back and for) to check and see if it is right under the surface. I listen to see if the sound quiets down and I check and see what the meter is saying.... especially if i am in a park where the change is usually just under the grass. hope that helps.