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EM16/EM16R VLF Receiver TX27 Transmitter
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Features
  • Measures the local tilt and ellipticity of VLF broadcasts and resolves values into inphase and quadrature components of VLF response.
  • Combined EMI6/16R instrument can detect a second earth-layer if the layer occurs within the VLF skin depth.
  • Maps resistive alteration for gold exploration.
General

The EM16 is a widely used EM instrument. The unit measures the local tilt and ellipticity of VLF broadcasts, and resolves values into inphase and quadrature components of VLF response. EM16 units have discovered several base and precious-metal ore bodies, and many water-bearing faults.

The EM16R attaches to the EM16 and uses a pair of electrodes to measure the apparent resistivity of the earth. The combined EM16/16R instrument can detect a second earth-layer if the layer occurs within the VLF skin depth. In addition, the EM16/16R can map resistive alteration for gold exploration.

The TX27 is a portable VLF transmitter that supplies a VLF field for surveying with the EM16/16R if remote broadcasts are weak, intermittent, or poorly coupled with the target. For EM16 surveys the TX27 antenna consists of a long (1km) grounded wire.

Specifications

EM16/EM16R
Measured Quantities:
  • EM16: Inphase and quadrature components of the secondary VLF field, as percentages of the primary field
  • EM16R: Apparent resistivity in ohmmeters, and phase angle between Ex and Hy
Sensors:
  • EM16: Ferrite-core coil, tuned by plug-in crystal.
  • EM16R: Stainless-steel electrodes, separated by 10m, impedance of sensor is 100MOhms in parallel with 0.5pF
Measurement Ranges:
  • EM16: Inphase: 150%, Quadrature: 40%
  • EM16R: 300, 3000, 30000 Ohm-m, Phase: 0-90
Weights:
  • EM16: Operational: 1.8kg, Shipping: 6.2kg
  • EM16R: Operational: 1.5kg, Shipping: 6kg
Primary Field Source: VLF broadcast stations
Operating Frequency: 15 to 30kHz, depending on VLF broadcasting station
Power Supply: EM16/16R - 6 alkaline 'AA' cells
Dimensions: EM 16 and/or EM16R: 53 x30 x 22cm

TX27 VLF Transmitter

Weights:
  • Operational: 29kg
  • Shipping: 68kg
Primary Field Source: Grounded wire or 500 x 500m loop, current adjustable, 0 to 2A
Operating Frequency: 18.6kHz
Power Supply: 120/240V, 350W motor-generator
Dimensions: 88 x 29 x 39cm
Instrument supplied with console, crystal for TX27 VLF frequency, shipping case and manual.