One of the big complaints with early T2 versions was it's affinity to rusty steel bottle caps, like many modern motion ID units have, especially with a DD coil. Well, the F75 really goes above & beyond toward handling caps & flat iron with 5 different methods available. Just the "bc" process alone seems to work very well as in my tests I only dug 1 very shallow rusty cap. Also the condifence bars & ID # bounce all over the place while a coin sticks....
here are the 5 methods
1. Search with the 3b (bottle cap) process using the PROCESS # feature. This method calculates visual ID differently in order to cause steel bottle caps to read lower on the scale, and to register less consistently. A desirable object such as a coin will usually produce numeric values that are fairly consistent in both directions of sweep.
2. Search with the dP process. This method calculates visual ID differently in order to cause steel bottle caps to ID lower on the scale and to register less consistently. It also produces more audio clues to the character of the target.
3. Lift the searchcoil. Within 2 inches of a Bi-Axial searchcoil, the crossed magnetic fields of the Double-D construction can produce anomalous responses. If the object feels shallow (strong signal, narrow response, or multiple responses in a single sweep) and is giving consistent high readings like a coin, raise the searchcoil 2 to 3 inches and try again. A coin will almost always continue to give consistent readings unless it is right next to an iron object. A steel bottle cap that is at least 3 inches away from the searchcoil will usually produce readings that bounce around from medium to low numbers.
4. Sweep the rear of the searchcoil over the center of the target, or sweep rapidly.
a. If the ID# is repeatable in the range of 68 to 72, when passing the center of the searchcoil over the target at a normal speed, then the target is probably a dime or copper penny.
b. If the ID# is not in the range of 68 to 72 then:
i. Sweep the back end of the searchcoil over the target. If tones change from high to low, the target is probably a bottle cap.
ii. Sweep the center of the searchcoil rapidly across the target.
1. If tone and ID# drop, it is probably a bottle cap.
2. If a bottle cap, then the faster you sweep, the lower the tone.
5. Use the Confidence Indicator
Coins will usually produce a high confidence level, whereas steel bottle caps and other trash will usually indicate a low or erratic confidence, even if the ID numbers are consistently in the range of a coin. Confidence level is useful even if not using the dP or 3b processes.
here are the 5 methods
1. Search with the 3b (bottle cap) process using the PROCESS # feature. This method calculates visual ID differently in order to cause steel bottle caps to read lower on the scale, and to register less consistently. A desirable object such as a coin will usually produce numeric values that are fairly consistent in both directions of sweep.
2. Search with the dP process. This method calculates visual ID differently in order to cause steel bottle caps to ID lower on the scale and to register less consistently. It also produces more audio clues to the character of the target.
3. Lift the searchcoil. Within 2 inches of a Bi-Axial searchcoil, the crossed magnetic fields of the Double-D construction can produce anomalous responses. If the object feels shallow (strong signal, narrow response, or multiple responses in a single sweep) and is giving consistent high readings like a coin, raise the searchcoil 2 to 3 inches and try again. A coin will almost always continue to give consistent readings unless it is right next to an iron object. A steel bottle cap that is at least 3 inches away from the searchcoil will usually produce readings that bounce around from medium to low numbers.
4. Sweep the rear of the searchcoil over the center of the target, or sweep rapidly.
a. If the ID# is repeatable in the range of 68 to 72, when passing the center of the searchcoil over the target at a normal speed, then the target is probably a dime or copper penny.
b. If the ID# is not in the range of 68 to 72 then:
i. Sweep the back end of the searchcoil over the target. If tones change from high to low, the target is probably a bottle cap.
ii. Sweep the center of the searchcoil rapidly across the target.
1. If tone and ID# drop, it is probably a bottle cap.
2. If a bottle cap, then the faster you sweep, the lower the tone.
5. Use the Confidence Indicator
Coins will usually produce a high confidence level, whereas steel bottle caps and other trash will usually indicate a low or erratic confidence, even if the ID numbers are consistently in the range of a coin. Confidence level is useful even if not using the dP or 3b processes.