A funny thing happened with the E Trac today.

[davew0710]

The weather improved enough that I could get out today and hit several different sites. One was a tot lot. In the middle of detecting the playground, I started finding quarters with a 28-47 signal. I found 4 quarters in a row reading 28-47. Before this and after this, the quarters were coming in at the usual 12-47 signal. Anyone have any ideas why this would happen?
Nothing was different from the rest of the site in the area I was finding the 28-47 quarters. My batteries were down to 2 bars, but the signals for everything else were what you would expect for the coins I was finding.

 

[TheMarshall]

Possible cause....mineralized patch of ground.

Any in-filled ground evident? Black soil matrix? Cinder, ashes, or old bricks?

Doesn't this experience back-up my recommendations of previous posts.....be prepared to dig targets even with such extended Fe numbers?

You would not even hear such a 'corrupted' target in a tight coin program.

Out of curiosity....what screen pattern / settings were you running during these finds?

 

[davew0710]

I was running quickmask with only the 30-35 ferrous blocked out. I like hearing the tones and figuring what I want to dig more than depending on the numbers.
Fast recovery was on, but other than that nothing special.
No signs of fill or cinders.

 

[Rick(ND)]

Is there a possibility of iron in the ground like nails. The reason I say this is I like to check some of my iffy signals in quick mask like i did with the Explorer , but seen many good targets show iron. In my factory coin program +3 on auto sensitivity with trashy ground on I get a signal that is kind of iffy as the audio is mostly repeatable depending on how you come at the target. The ferrous number are reading around the 12-18 numbers while the conductivity is around the 42, now I go to quick mask and the numbers are in the high 20 to around 33 and never seem to get back down to less than 25 or so, the audio is better too. Now go back to the factory coin pattern and I can get the lower number now and not as repeatable in the audio. When dug it has been a rusty nail with a wheat penny and whey I feel in the quick mask it seems to lock on the iron better on the ID more than while in the factory coin pattern. Myself I have seen this several times already while in area that have more nails in them.

 

[rbholt80]

I have given up on the vdi hitting near were it should. I run just some iron reject and dig anything that sounds good. The places im hunting are extremely trashy and some have very bad minerals or charged soil mixed in. Im still new to the e-trac and im still haven a hard time going from fisher to minelab. But i have found coins that would read low on FE scale. These FE #'s are driven me crazy

 

[Steve from Ohio]

I may have a possible answer.......

Was there any fertilizer put on the ground lately?

I have noticed that certain fertilizers seems to change the FE numbers. I found that out yesterday when I put down some fertilizer on my grass. It rained last night and then I was out in the yard fooling around with the E-trac. I hit a penny but it read 16-40 in the ground. Found a few more with the same numbers.

I had found pennies in my grass that were 12-40 before I fertilized. I did eventually get the numbers back to where they should be by doing a noise cancel. That seemed to do the trick. I was at a school late on in the day and the pennies read normal.

Not sure if that was your problem or not.

 

[3RINGER]

Davew0710 Great post, with your Q and the guys reply it helped me figure out more about the readings I was getting on coins. some of the coins had a rich orange colour to them and that may have been from the fertilizer being used in the yard. Like rbholt80 said though if it sounds good go for it. if it's not a coin you can only learn from it in the long run.

HH

 

[digitrich]

You can get that same reading in an air test by just sweeping a quarter across the coil and tilting it. It would be a good idea to check all targets on edge or tilted and record the readings so that you don't pass some up.