Sensors & Software pulseEKKO Product Manual page 141

CMP or WARR Surveys
When the Survey Type is set to CMP or WARR, the Antenna Separation parameter changes to
the Starting Antenna Separation parameter. This is the distance the transmitting and
receiving antennas are separated for the first trace of the CMP or WARR survey. Based on the
antenna frequency, use the recommended separation in the table above.
6.2.5 Antenna Polarization
All the pulseEKKO antennas and transducers have the flexibility to allow different orientations
with respect to each other. Press Antenna Polarization to display the screen in Figure 6-25
where the user can set the Antenna Geometry.
Most surveys are conducted in the Broadside-Perpendicular configuration. This is because the
maximum amount of energy transmitted (and received) is perpendicular to the long axis of a
dipole antenna. Figure 6-24 shows the emitted (and received) radiation pattern for a pair of
antennas.
There are times, however, when the geometry needs to be changed. Factors to consider are:
1. Orientation of subsurface reflectors
2. Minimizing airwaves
3. Collecting a wider swath of data
4. Minimizing noise from external radio sources
Frequency (MHz)
12.5
25
50
100
200
250
500
1000
Figure 6-24: Radiation pattern for a pair of antennas
Minimum Antenna
Separation (m)
8
4
2
1 (or 0.5)
.50
0.40
0.23
0.15
129
System Configuration
Minimum Antenna
Separation (feet)
25
15
5
3 (or 1.5')
1.5
1
0.75 (9 in)
0.5 (6in)