Geonics EM38-MK2

Overview

Geonics EM38-MK2

The EM38-MK2 is a conductivity meter that uses an electromagnetic inductive technique to record the subsurface’s apparent conductivity and magnetic susceptibility. A primary magnetic field is created by the EM38’s transducer. This creates a voltage that produces a secondary magnetic field in relation to the signal’s surroundings and is measured by the EM38.

The EM38-MK2 is employed in archeology, agriculture, and general soil sciences. It is primarily used by agronomists to determine a soil’s salinity, moisture, and clay content. With this information, farmers look at differetn areas of their cropland and determine the proper irrigation and fertilization needs.

The EM38-MK2 possesses one transducer and two receivers with an intercoil spacing of 0.5m and 1m. This means in the vertical dipole position the EM38-MK2 can reach depths of .75 and 1.5 meters whereas in the horizontal dipole the instrument can reach depths of 0.375 and 0.75 meters.

EM38-MK2 Configurations

The EM38 comes in a couple different configurations. The most common configuration of the EM38-MK2 possesses two receivers discussed above. There is an older EM38-MK1 that possesses one 1m sensor, which is no longer produced. There is also an EM38-4 in the research and development stage at Geonics LTD that possesses four receivers at spacings of 0.5m, 0.75m, 0.88m, and 1m for greater resolution. The EM38-4 also comes with inversion software to map shallow bedrock in real time.

EM38-MK2 Considerations

For large scale surveys, the EM38-MK2 is often used in auto mode for continuous readings on a specialty-made trailer pulled behind a tractor or UTV. This is often done with large surveys with a GPS. Smaller scale surveys can be performed manually with lines and stations where readings are taken via a trigger button. A drop-down extender handle allows the user to set the EM38-MK2 on the ground to take deeper readings without the user needing to bend over at each station or reading.

Typical EM38-MK2 Packing List

1 x EM38-MK2
1 x Normal Drop Down Extender Arm Handle Button
1 x Calibration Stand
1 x Cable (EM38 to Data Logger)
1 x Cable (EM38, Data Logger, Extender Arm)
1 x Power Supply (110 VAC to 12 VDC)
1 x Belt Battery Pack
1 x USB Flash Drive with Manuals and Software
1 x Paper Copy Manual
1 x Shipping Case (45x12x11, 45 lbs)

User Manuals

EM38-MK2 Specifications

MEASURED QUANTITIES:
1: Apparent conductivity in millisiemens per metre (mS/m)
2: In-phase ratio of the secondary to primary magnetic field in parts per thousand (ppt)
INTERCOIL SPACING: 1 and 0.5 metres
OPERATING FREQUENCY: 14.5 KHz
MEASURING RANGE:
Conductivity: 1000 mS/m
In-phase: ± 29 ppt for 1 m
In-phase: ± 7 ppt for 0.5 m
MEASUREMENT RESOLUTION: ± 0.1 % of full scale
MEASUREMENT ACCURACY: ± 5 % at 30 mS/m
NOISE LEVELS:
Conductivity: 0.5 mS/m;
In-phase: 0.02 ppt
DATA OUTPUT: RS-232 serial port, Bluetooth
POWER SOURCE: 9 V disposable battery, external rechargeable battery pack
BATTERY LIFE: up to 5 h continuous for MN1604; 12 h continuous for L522; 25 h for rechargeable battery pack
OPERATING TEMPERATURE: -40°C to + 50°C
INSTRUMENT DIMENSIONS: 107 x 17 x 8 cm
INSTRUMENT WEIGHT: 5.4 kg