Gains, Range And Clip Levels - Gecko Compact Product User Manual

2. Insert anchor thread-side up into hole. Gently tap with hammer until flush with surface
3. Insert the tapered end of the anchor setting tool into the anchor.
4. By tapping down the embedded spreader, the anchor will bite into the hole. A few firm
taps of your hammer will be enough to punch the spreader to the bottom of the anchor.
5. Screw the supplied 8mm threaded rod into the anchor. After tightening, ensure the rod
cannot be pulled out of the ground by hand.
6. Using the central hole in the Gecko, slide the unit over the threaded rod.
7. Orienting your recorder depends on your application. We recommend:
a. For earthquake monitoring, rotate the Gecko until the arrow is pointing North
b. For structural monitoring, point the North arrow along an axis of your structure
8. Loosen the upper locking nuts on the adjustable feet and screw the feet in or out until
the bubble on top of the Gecko is centred indicating that the chassis is level.
9. Screw the locking nuts up to the base of the Gecko so that the feet can no longer be
adjusted.
10. Use the supplied flanged plastic nut to lock the Gecko down onto the threaded rod.
Hand tightening is sufficient to tie the Gecko down for better coupling and to avoid
accidental movement.
If you need to move your sensor, you can reuse the threaded rod and locking nut.
Additional M8 Ramset DynaSet Drop-in Anchors can be purchased at hardware stores, or
contact us if you require any spare parts.

Gains, range and clip levels

Gain Clip Level
x1 ±695 mm/s
x2 ±347 mm/s
x4 ±174 mm/s
x8 ±89 mm/s
x16 ±43 mm/s
x32 ±22 mm/s
x64 ±11 mm/s
x128 ±5.4 mm/s
x256 ±2.7 mm/s
x512 ±1.4 mm/s
The Gecko SMA uses ±4V output range sensors, so to maximise the resolution of the data
the Gecko SMA will be shipped with a gain of x4, which will use 80% of the Gecko's dynamic
range. Increasing the gain further will reduce the clip level of your SMA.
The Gecko Blast's geophones have a nominal output of
28.8V/m/s. The Gecko recorder has an input range of ±20V at a
gain of x1, which equates to a clip level of 694.4mm/s. The
typical noise level at a quiet site is less than ±0.005mm/s, and
at a gain of x1 the Gecko Blast resolution is about 0.0001mm/s,
or about 50 times lower than a typical monitoring site, so you
should not need to change the gain. If you do increase the gain
for higher sensitivity, the clip level will be affected as estimated
in the table (left).
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