Fisher F75 pinpointing depth questions

cobb05

Full Member
Joined
Feb 17, 2010
Messages
101
Location
Ohio River, WV
So I've been getting to know my new Fisher F75 se over the past month or so but I am finding something strange when pinpointing. I'm not sure if its something I am doing or if its the detector itself. It seems when I am pinpointing the depth reading always wants to read 5. If its not a coin it almost always reads 5 inches. If it is a coin it will read from 4-5 inches. Rarely does it ever read less than 4 inches and there are many times it will read 6-7 inches but when I retrieve the target its literally 2 inches in the ground resulting in me digging a much deeper hole than I need to. My whites M6 was always spot on which allowed me to dig those pop tab/ gold range signals based off of depth. However now I can't get that extra clue. Anyone else have this happen or any advice?
 
So I've been getting to know my new Fisher F75 se over the past month or so but I am finding something strange when pinpointing. I'm not sure if its something I am doing or if its the detector itself. It seems when I am pinpointing the depth reading always wants to read 5. If its not a coin it almost always reads 5 inches. If it is a coin it will read from 4-5 inches. Rarely does it ever read less than 4 inches and there are many times it will read 6-7 inches but when I retrieve the target its literally 2 inches in the ground resulting in me digging a much deeper hole than I need to. My whites M6 was always spot on which allowed me to dig those pop tab/ gold range signals based off of depth. However now I can't get that extra clue. Anyone else have this happen or any advice?

What size coil are you using?
Lay a coin on top of clean ground,,a nickle.
Then go to pinpoint over to side of coin, then come over the coin at various distances.
See how the actual distance from coin compares to meter reading.
Consider trying depths from 3-7" and see how close the detector reads.
 
Im using the stock coil it came with. Im going to switch out for the 5 inch coil that I also got with it today and run it some and see if it does the same thing. If it does do the same thing, what should my next step be?
 
Im using the stock coil it came with. Im going to switch out for the 5 inch coil that I also got with it today and run it some and see if it does the same thing. If it does do the same thing, what should my next step be?

The detector's depth meter is scaled for stock coil use, not small coil use.
This also applies to most other Vlf detectors that possess depth meters.

Did you do what I suggested above?
If so what were the results?
 
so i put some clad down on the ground and held a yard stick upright. What i found is its a good 3-4 inches off. even when its almost touching it it wants to read 3+ inches. According to the yard stick if I'm really at 3 inches, the machine reads 5 or higher. If I'm at 4-5 inches on the yard stick, the machine reads 7 inches. Once i moved the coin to a hard surface with no grass at all it was still off. However it was as if the machine had a grey area that it always reads 5 inches. However once I really get to 2 inches the machines tries to catch up and reads a little closer to what its really at.
 
so i put some clad down on the ground and held a yard stick upright. What i found is its a good 3-4 inches off. even when its almost touching it it wants to read 3+ inches. According to the yard stick if I'm really at 3 inches, the machine reads 5 or higher. If I'm at 4-5 inches on the yard stick, the machine reads 7 inches. Once i moved the coin to a hard surface with no grass at all it was still off. However it was as if the machine had a grey area that it always reads 5 inches. However once I really get to 2 inches the machines tries to catch up and reads a little closer to what its really at.

Make sure there is no deep iron, or other metal in the grass test area....
 
so i put some clad down on the ground and held a yard stick upright. What i found is its a good 3-4 inches off. even when its almost touching it it wants to read 3+ inches. According to the yard stick if I'm really at 3 inches, the machine reads 5 or higher. If I'm at 4-5 inches on the yard stick, the machine reads 7 inches. Once i moved the coin to a hard surface with no grass at all it was still off. However it was as if the machine had a grey area that it always reads 5 inches. However once I really get to 2 inches the machines tries to catch up and reads a little closer to what its really at.

Your distance displayed for depth is dependent on coin size.

For example a 6" deep dime laying flat,,,it may read 7" on meter.
A 6" deep quarter may read only 6" on meter.
This is why I told you to use a nickle. It is in the middle size wise.
 
There is definitely an overestimation issue regardless of the target it seems. I've contacted fisher to see what can be done to resolve it. If it will take multiple weeks to get it fixed, I may wait until cold weather hits before sending it in and just put up with the overestimation for now. Not a complete deal breaker at this point but something I will want addressed as I become more proficient with the machine. Thanks for all the input. If anyone else has any, Im all ears!
 
So I finally got a free few minutes this evening and did some comparing. My whites M6 is extremely accurate with target depth estimation while the 75 is 2-3 inches more on its depth estimation for every target I have in my test bed. if it says 5 inches my M6 reads 2-3. If it reads 7 inches my M6 reads 4-5 inches. Knowing this now, I can at least compensate until I can get it looked at by them. However, I still like the 75 more. Its just a powerhouse and amazes me how hard it will hit deeper targets compared to the M6!
 
So I finally got a free few minutes this evening and did some comparing. My whites M6 is extremely accurate with target depth estimation while the 75 is 2-3 inches more on its depth estimation for every target I have in my test bed. if it says 5 inches my M6 reads 2-3. If it reads 7 inches my M6 reads 4-5 inches. Knowing this now, I can at least compensate until I can get it looked at by them. However, I still like the 75 more. Its just a powerhouse and amazes me how hard it will hit deeper targets compared to the M6!


My 75 is always 3 inches deeper on a coin. I learned this the first week I had it. I'm ok with it. The advantages it has in speed and separation along with depth far out weigh being a few inches off on actual depth of a coin. I have so much time on the 75 now I rarely over dig a target.
 
Yea I went back out yesterday and caught on pretty quick and am no longer over digging the target nearly as much! I absolutely love the 75! Thanks for the input everyone!
 
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