White’s Electronics MXT 300 - Manual (Page 19)

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Gain Adjustment (continued)
5. In the Prospecting MODE the use of the SAT
(variable self-adjusting threshold) control will help
to maintain a smooth THRESHOLD "hum" partic-
ularly at higher GAIN settings and will be covered
in a later section.
6. While using a steady slow search coil sweep
speed, simultaneously advance GAIN towards
"+3". If the "OVERLOAD-REDUCE GAIN/
LIFT LOOP" alert keeps popping up on the dis-
play, if a quiet smooth background THRESHOLD
"hum" doesn't continue, or if ground noises are a
problem reduce GAIN.
7. The trash I.D. capability of the MXT 300 also
functions more accurately when the GAIN is set
at a level which allows for smooth operation. Too
much GAIN can cause bad ground to distort the
proper identifi cation of iron and non-iron targets.
8. Note: It is normal to hear changes, clicks or soft
beeps, coming from the audio (speaker) during
GAIN adjustments as the circuit shifts between
hardware and software gains (different electrical
parts of the circuitry). The GAIN control adjusts
both the hardware gain (hard physical compo-
nent) as well as the software gain (computer code)
alternating between the two throughout it's range.
As the MXT 300 shifts between these two intricate
parts of the circuitry an audio indication notes the
transitions. This can be helpful. If you adjust the
Gain slightly, the audio notes a signifi cant rather
than slight change.
9. The MXT 300 provides more GAIN control
range than is typically useful assuring performance
is not left on the plate due to restricted assess/
range. Likely few areas will allow maximum
GAIN (full clockwise) without at least some degree
of radical (noisy) operation. Setting in the + area
requires a high degree of operator skill.
SAT SPEED CONTROL
(Prospecting Mode Only)
Chapter 5 MXT 300 Controls
GAIN Control
Gain Adjustment (continued)
If, of course, "OVERLOAD-REDUCE GAIN/
LIFT LOOP" message is displayed common for
very nasty ground mineralization, you must heed it
and reduce the GAIN rather than raise it.
3. The object of increasing the GAIN is to get
the maximum available depth from the detector
WITHOUT causing the "OVERLOAD-REDUCE
GAIN/LIFT LOOP" message to appear which
indicates an overload of the circuit.
4. In addition, any increase in GAIN adjustment
should NOT BE at the expense of maintaining a
smooth and constant THRESHOLD "hum". False
signals, beeps and static from bits of mineralization,
erratic behavior, and lapses in THRESHOLD all
can be the result of running with too much GAIN.
Chapter 5 MXT 300 Controls