User's Manual

www.malags.com
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operating in areas where recharging of the batteries is not
possible.
NOTE: Alkaline batteries will NOT operate the Shielded
Electronics Unit.
7.2 Optical fibres
The RAMAC/GPR Radar Control Unit communicates with the
transmitter and receiver electronics through fibre optic cables.
The data transfer rate through the fibres is up to 4 Mbytes/sec
and they operate:
?? Trig signals to the transmitter element from the CUII
?? Trig signals to the receiver element from the CUII
?? Data from the receiver element to the CUII.
The antennas can be operated through the standard set of
optical fibres for RAMAC/GPR. These optical fibres come in a
standard length of 4 m. They are also available in lengths up to
100 meters or more for applications such as CMP
measurements or cross scanning where the two antennas
have to be separated from each other.
For the shielded antennas Malå GeoScience have designed a
special set of fibres housed in a plastic hose for convenience
(Fig. 5.4 and 6.1). This is to protect the fibres from damage
when operating the antenna in e.g. rough environments. The
attachment of the optical fibres to the antenna includes a metal
cover over the optical connectors. This is in order to protect
the connectors and the fibres at their attachment on the
antenna. When sampling at high sampling frequencies as e.g.
100 000 MHz the bending of a trig fibre can play an important
role for the time displacement of the pulse in the time window.
This is due to the short time interval that each sample
represents at these frequencies.