User's Manual

pulseEKKO PRO 3-System Setup Parameters
37
3.2.4 Antenna Separation
As the transmitting and receiving antennas are moved along a survey line, it is important that a separation
be maintained between them. When the antennas are mounted on a cart the antenna separation is fixed,
but when the antennas are not fixed in position, it is common to use a rope or measuring tape to maintain
the proper separation (See Figure 6-4 on page 84).
This parameter is set under System Setup - GPR Parameters - Antenna Separation.
The Antenna Separation value will be set to a default value based on the antenna frequency selected
(Section 3.2.1: P34) as shown in the table below.
The rule of thumb is that the minimum antenna separation should equal the antenna length. For example,
100 MHz antennas are 1 metre long and should be kept about 1 metre apart during a survey. If the
antenna spacing is too small, receiver electronics may be overloaded by the transmit signal resulting in
data clipping (see Appendix B: GPR Signal Processing Artifacts for a discussion of this problem).
Note that this parameter has no meaning for any mode of operation where the antenna separation
changes such as when collecting a CMP/WARR profile.
Frequency
(MHz)
Minimum Antenna
Separation
(metres)
Minimum Antenna
Separation
(feet)
12.5 8 26
25 4 13
50 2 6
100 1 3
110 1 3
200 0.5 1.5
250 0.38 1.25 (15 in)
500 0.225 0.75 (9 in)
1000 0.15 0.5 (6 in)