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F75-MANUAL(122811).qx 12/14/12 9:04 AM Page 20
F75
Comprehensive Operating Manual & Guide to Metal Detecting
Discrimination Mode (continued)
NOTCH
Unlike Discrimination Level, which eliminates all targets from the left of the scale to the right,
NOTCH can eliminate and re-include targets within the scale displayed at the top of the display. Inclusion or exclusion of target ranges is indicated with a half-crossed or crossed icon.
To demonstrate how to set a notch, follow this instruction at first use.
1. Reset all detector values to default: a. turn detector off b. press-and-hold red MENU button and push-forward-and-hold Toggle Switch c. turn detector on while continuing to hold MENU and Toggle d. release Menu and Toggle.
2. Press MENU button 4 times to move down to the NOTCH feature
-then rotate the SETTINGS knob to the right until the number 40 appears.
-then press MENU again to accept this notch value.
3. Notice that a thin line appears across the word “TAB” printed on the top of the display.
4. Press MENU again to exit the NOTCH feature.
5. Targets in the first 1/2 of the TAB range (TAB range is from 36 to 55) will be eliminated from detection.
6. A half-slash will be permanently displayed across the top-left of the word “TAB.”
NOTCH allows you to select target ranges equal to 1/2 of each category for inclusion or exclusion from detection. As you rotate the knob, the target indicator will appear above the range currently selected. If you set the notch value anywhere within the range, the notch value will not necessarily stop at this number, notch ranges are fixed as follows:
1. 1-7 iron
2. 8-15 iron
3. 16-20 foil
6. 31-35 nickel
7. 36-45 tab
8. 46-55 tab
4. 21-25 foil 9. 56-60 zinc
5. 26-30 nickel 10. 61-65 zinc
The following are characteristics of NOTCH programming:
• As you rotate the knob to enter a notch range, the target indicator block at the top edge of the screen illuminates to show you the range you are in.
• After you have selected a notch, a slash is illuminated over that range, indicating that all targets within that range (see chart above) are eliminated from detection.
• When you enter the program to make a change to the notch settings, you are
changing the status of the notch. If no slash is illuminated and you press MENU to set a notch range, you will be notching-out this range. If a slash was previously illuminated and you press MENU to set this notch range, you will be notching-in this range.
• Programming a notch range always reverses the status of the notch.
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F75
Comprehensive Operating Manual & Guide to Metal Detecting
LCD Visual Display (continued)
Since different metal objects can produce similar signals, and since minerals in the soil can distort the signals, the probable target ID's are just that -- probable. There is no way of knowing for sure what's buried other than to dig it up. Experienced metal detector users have a rule of thumb -- "when in doubt, dig".
DEPTH
When the trigger is pulled to facilitate pinpointing an object, the 2-digit numerical display indicates the approximate depth of the object, in inches, based on the assumption that the object is a typical U.S. coin. Small objects will read deeper than they actually are, and large objects will usually read shallower than they actually are.
The DEPTH bar graph on the left of the display divides target depth into shallow, medium, and deep. This depth range appears while searching, and is less accurate than the value derived using the pinpoint toggle switch.
Bar graph ranges for a coin-sized object are Shallow (0-4inches), Medium (4-8inches), and
Deep (8inches +).
CONF (Target Confidence Indicator)
This 6-segment graphic indicates how confident the detector is of the 2-digit target identification it has assigned. If all 6 segments are displayed, you can be confident that the target ID is accurate. If 3 or fewer segments are displayed, the confidence is very low.
Junk targets tend to produce lower confidence indications than coin targets of similar electrical conductivity. Sloppy sweep technique also reduces the confidence indication. You can use this indicator to train yourself to sweep more skillfully.
Fe
3
O
4
BAR GRAPH (magnetite)
This bar graph displays the magnetic mineralization factor, or magnetic susceptibility, of the soil.
Magnetic susceptibility is expressed in terms of the percent volume of the iron mineral magnetite, which most black sand is made of. The depth to which objects can be accurately identified is strongly influenced by the magnetic susceptibility of the soil. High Fe
3
O
4 values have a greater effect on detection depth in the Discrimination mode than in the All Metal mode. For the most accurate Fe
3
O
4 reading, pump the searchcoil as though you were ground balancing.
Fe
3
O
4 approx.
Range micro-cgs Description
3 7,500 uncommon but not rare, heavy mineralization
1 2,500 heavy mineralization, not uncommon in goldfields
0.3 750 heavy mineralization, but not uncommon in some regions
0.1 250 medium mineralization, typical
0.03 75 light mineralization, but common
0.01 25 light mineralization, your G. B setting may also be low blank <14 quartz & coral white beach sands
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