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EM16/EM16R VLF Receiver
TX27 Transmitter
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.
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