8
Fig. 2.6.
The MIRA option connected to the ProEx control unit. The metal plate and place for securing
screws are marked.
2.3 Antennas
The MIRA system is designed to handle shielded separable antennas only, no other antennas can be
used with the MIRA system. The MALÅ separable antennas are designed to show as similar response
(signature) as possible and each data channel in the array is tested individually with regard to this
parameter.
The MALÅ shielded separable antennas are available with the centre frequencies of 200MHz, 400MHz
or 1.3GHz. These frequencies will cover investigations ranges from 0 to approximately 6 m depth in
non-conductive ground.
These antennas have one power connector and one trig connector. The receiver antennas are also
equipped with a connector for the digital data.
For each trig line there’s a LED on the antenna. This LED, when blinking, tells that the trig signals are
received by the electronics inside the receiver and transmitter antennas. Similarly there is a LED
telling that digital data is leaving the receiver antenna, when blinking.
The antennas contain all electronics for generating the impulse, sampling the incoming signals and
digitise it to 16-bit. The raw 16-bit data is transferred to the array-
option where it’s buffered for later
transport to the PC for final storage and display. In Fig. 2.7 below available MIRA antennas is shown.
