dropped samples. When this occurs, an entry will be written to the log (xml) files in the format
“sampling gap X us at sample Y”. There is an
experimental
option under the Tools menu ‘Zero Fill
Dropouts’. This function will attempt to fill any sampling gaps with a series of zeros. This
may be
useful where more precise sampling timing is required.
3.4
Deployment hardware
The anchoring scheme used is very dependent on the goals of the data collection in combination
with the deployment environment. Thankfully SoundTraps are more easily deployed than traditional
acoustic recorders due to their small size. A SoundTrap ST400
’s
weight in water is approximately 0.2
kg.
Most often the hydrophone is located near the sea floor, using an anchored line. This involves
running a line between a heavy anchor weight and either a surface or sub-surface float. A sub-
surface float is often best, as it is less affected by weather/swell and is less likely to be tampered
with. The SoundTrap should be attached to the line a couple of meters off the bottom. Two grooves
around the housing provide attachment points for cable ties. This bottom cable tie should pass
through the associated hole so it cannot slip off.
Avoid
using the hydrophone cage as an attachment point. This is too close to the hydrophone and
may introduce unwanted noise into the recordings.
Be mindful that a taut line combined with strong currents may result in ‘cable strum’ which may
disrupt your recordings. In this case a rigid frame may be more appropriate.
Ensure there are no metal objects in close proximity (3cm) to the SoundTrap eg using metal brackets
or wire rope. Doing so may lead to galvanic corrosion of the instrument housing.
Don’t mount your SoundTrap so close to the sea floor that it may become covered in sand or mud.
This may also lead to corrosion and corrosion instrument housing.
3.5
Software updates
New software releases will be made available via the Ocean Instruments website. You may which to
subscribe to our email list in order to receive notification of these updates. The update procedure is
