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Chapter 3: GEM3D receiver setup.
Connecting to the GEM3D receiver: The GEM3D receivers have panel connections for the
power, Ethernet cables, ground, E-field dipoles, and magnetic sensors. We will look at each
individually:
A.
Panel-1 Electric field terminals
Fig 10: GEM3D receiver E-field (telluric) connectors
Perhaps the most difficult part of setting the connections to the GEM3D receiver is properly
connecting the electric dipole cables to the terminals. The red and black terminals of CH1 are +
(red) and – (black) of E-field channel 1. . The red and black terminals of CH2 are + (red) and –
(black) of E-field channel 2. Channels 3, 4, 5, and 6 all have one or more common terminals as
follows: CH3 red is + and yellow is -. CH4 yellow to right is channel 4 positive and yellow to left
is channel 4 negative. CH5 yellow to right is channel 5 positive and yellow to left is channel 5
negative. CH6 yellow is positive and CH6 black is negative. All the yellow terminals share a
common connection to the terminals to the right and/or left of them.
IMPORTANT NOTE: Because of the nature of shared electrodes all surveys should be laid out
such that the first electrode in the line is the positive pole of Ex1. For example, if CH1 is Ey1 and
CH2 is Ex1 the electrode connected to the red terminal of CH2 should be the first electrode in
the profile line.
