User's Manual

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14
4 Unshielded antennas
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The unshielded antennas consist of separate transmitter and
receiver electronics to which the antenna elements are
attached. The antennas can then be used with antenna
handles, a skid box or an antenna sledge (see Chapter 10).
The complete RAMAC/GPR system is shown in Fig. 4.1,
where the antenna electronics are mounted to the antenna
elements together with wooden handles.
Radar
Control
Unit
Batteries
Trigger Status Box
Tx
Rx
Fiber Optic Cables
Spacers
Antenna Handles
Figure 4.1 Unshielded system connected with the 200 MHz
antennas and handles with 0.6 separators.
4.1 Antenna electronics
The unshielded antenna electronic unit for the transmitter
generates electromagnetic energy and transmits it to the
attached antenna elements every time a trigger signal is
received from the CUII through the optical fibre (labelled T).
These high amplitude pulses (typically 370V) are fed to the
antenna elements at a repetition rate of 100 kHz. The antenna
element transforms these pulses into radar impulses at a