17
2. THRESHOLD B
–
(THS-B) (BIAS)
Setting range 1-99
Factory preset at 50
Small Search Coils
When using small coils for finding small (tiny) targets, set the THS-B
(Bias) to an acceptable audio level
below
the neutral position.
From the neutral position, decrease THRESHOLD B with the
button until an acceptable threshold volume is created (i.e. not too
noisy)
This will boost target responses for smaller targets in the ground.
Process:
If a small coil is fitted test the THS-B out with a small target.
Swinging the coil over it will produce a
rising pitch response
.
Lower the THS-B by one count at a time and note the
improvement in detection distance.
Keep lowering THS-B until the background audio is at an
acceptable level.
Note: If THS-A is high then just a change of 1 or 2 on the BIAS will make the
QED too sensitive/unstable.
Medium Search Coils
Once the neutral position has been located, leave THRESHOLD B at
the neutral position to achieve a good even target response on both
smaller and larger targets in the ground.
Raise THS-A (Menu Item #3) to create desired audio threshold volume.
Large Search Coils
Once the neutral position has been located, increase THRESHOLD B
with the
button until the desired threshold volume is created.
This will boost target responses for larger targets in the ground.
Tip:
Use a test target of say
0.2g. If the 0.2g is louder
and more noticeable
after lowering THS-B,
then BIAS has been
achieved for better
detection on smaller
targets
Tip:
Use test target of approx.
0.2g.
If the 0.2g is faint or
undetectable, then BIAS
has been achieved for
better detection on larger
targets.
Tip:
When searching for
small targets: use a
small coil, a volume of
~30 or less, a gain of ~4,
with the THS-B set
below neutral until a
slight threshold is
created.
Summary of Contents for QED-PL2
Page 18: ...18 2 THRESHOLD B THS B BIAS Setting range 1 99 Factory preset at 50 Notes ...
Page 34: ...34 NOTES ...
Page 35: ...35 ...
