Installing the 40T
4.2.3
Other considerations
•
The sensor and cables should be situated well away from other electrical
cables and appliances. Stray radiation from these sources may interfere with
the sensor's electronics.
•
The sensor should be placed on a smooth, level surface free from cracks.
Small cracks tend to open and close slightly with changes in humidity and
temperature, causing the surface to move slightly.
•
All three of the sensor's metal feet must make good contact with the floor.
•
The signal cable from the sensor should rest loosely on the ground nearby, so
that vibrations are not transmitted along it.
•
If your recording or digitising equipment has front-panel indicators or
connectors, make sure it can be reached without disturbing the sensor.
•
The GPS unit needs to be in a location where it can see as many satellites as
possible. A location with a good view of the sky, preferably down to the
horizon, is recommended. If you are in the Northern Hemisphere, make sure
as much of the southern sky as possible is visible. Conversely, in the
Southern Hemisphere, make sure the GPS can see a large area of sky to the
north.
The GPS unit is supplied with a 15m cable to the digitiser.
4.3
Installing in pits
For outdoor installations, high-quality results can be obtained by constructing a
seismic pit.
Depending on the time and resources available, this type of installation can suit all
kinds of deployment, from rapid temporary installations to medium-term
telemetered stations.
20
Issue F - June 2019
