- 17 -- 16 -
4. Move the Search Coil
7. Depth Indicator
5. Make Use of the Sound to Help Discrimination
6. Make Use of Double Digits to Help Discrimination
When detecting, move the search coil at a constant speed, rather than sweep it
unsteadily. Keep the search coil parallel with and about 1/2 inch above the
surface. Do not swing it like a pendulum (See Fig. 17).
The following table is used as a preliminary guide. The approximate ranges of
the US dollar and pound coins are listed in the table.
When detecting, the double digits may be different slightly, depending on the
composition, size, shape, distance from the search coil and the speed of
detecting. The surrounding soil also affects the value. There are differences in
casting coins in different years. There is a wide range for gold, a thin ring is
about 45, and a rough ring and gold coin may reach up to 70-80. The table
below is just for reference.
For coin-sized objects, the depth indicator is accurate. But for large-sized or
irregular-shaped objects, the depth readings will be less accurate. If you sweep
the search coil at the same place several times, and it shows the same depth,
then the detection result is accurate. If the depth indicator varies, try to change
the angle of sweeping. There may be more than one target present.
Most valuable metal objects will send repeatable signals. If the signal isn’t
repeatable, it’s mostly a false signal. When there is a clear sound for buried
targets, you could find out the approximate target type and depth on the LCD
screen. And you could also move the search coil above the target objects fast
to get a more stable signal.
When detecting, you don’t need to stare at the screen all the time. And the
sound identification system will sound three frequency tones to help discriminate
the target metals.
Low Pitch-- 5￠nickel coin and so on;
Medium Pitch-- pull-tab, soda bottle and zinc coin;
High Pitch-- copper, aluminum and silver metal, such as 1￠, 10￠, 25￠and
so on.
Fig. 17
Range of Double
Digits
Possible Metal Dollar Coin Pound Coin
5P, 10P, 50P
20P, (10P, 50P)
01--40 Iron 1P
Nickel 5￠41--55
55--65 Pull-tab
65--75 Zinc, Soda Bottle 1￠ 1£
75--85 Copper, Aluminum 10￠，25￠ 2£, 2P
85--99 Silver 50￠, 1$
To Next Page
Loading...