F75: copper reading 99+ @ 8.5 inches?

Settings: 89 Sens, 6 disc, PF mode
Dirt: GB @ 82

Hunting in a soccer field in a park, I located an object that was reading 97-99 that repeated nearly 80-90% of my sweep angles and read as a small metal source when pinpointing. I dug the whole to about 8 inches and swept again, this time the object read 99 - ++. At this point I'm thinking I must have hit deep iron because I never get coins in that VDI range. To my surprise, less than half an inch further I find a 1980 copper penny. Surprised, I laid the copper penny on the bottom of the whole (8.5" deep) and swept it. Read 99 - ++ as before. I then pulled the coin out and swept again in all-metal to see if I was getting some sort of masking - nope, no masking.

1. Should I be concerned that the detector is reading a copper penny @ 8.5" as 99+?
2. Most of my soil around here GB's between 80 and 90 with very little, if any, Fe showing on my mineralization meter. What does that tell me about my soil?
3. If I find a 1980 penny at 8.5", should I be moving on if I'm looking for pre-64 silver and wheaties?

New coin at that depth = Fill-dirt or bad sink-rate dirt. I'd move to another location. Sounds to me like "silent masking" iron and/or bad mineralization causing a "99"+ on your VDI. I would have tried to bury the coin about another 1/2" deeper in this soil...... and see if it suddenly ID's as iron. This would indicate fairly high mineralization soil.

Tom

Thanks for the feedback - what does the GB of 80/90 tell me about the soil?

Black soil/magnetite...... can be moderate. Your Fe3O4 bargraph will tell you the severity.

Tom

Tom,

How do you know that 90 GB is black soil? Experience or is this information somewhere for all of us to see. Also, what would be considered and ideal ground balance number?

I believe I read that in the f-75 instructional booklet, can't be sure...but i think so...check it out.

HH

Yes, It's in the owners manual. Ideal GB is when you GB the unit.... and nothing changes. You can manually change the GB setting....... and try GB'ing the unit.... and still..... nothing happens. This means inert dirt. Zero interference from ground minerals. The higher the mineralization.... the more electromagnetic attenuation (depth loss) and ID inaccuracies ensue. Neutral dirt (like Florida dirt/sand) will present identical dirt performance and air-test performance.

Tom