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VHF Radio Call Sign:
WDE4414
Iridium phone cockpit:
00 - 88 1677 72 7018
Iridium spare 1:
00 - 88 1621 41 8079
Iridium spare 2:
00 - 88 1621 44 3804
Emergency Beacon:
ID: ADE90 05931 C34D
Handheld Emergency Beacon:
ID: LC 4652
Hovercraft registered in Delaware, US:
DL 1519 AB

Maintenance



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SEISMIC PROFILING


A 20 inch3 Bolt airgun is suspended from the solenoid-end.

Air bubbles from a shot.

1.  SINGLE HYDROPHONE


We have been using:

1.1  Splicing of hydrophone cable


Hydrophones are normally ordered unterminated. In order to splice the hydrophone cable to a suitable underwater pigtail cable (which is delivered with one connector; the other side is open) an inline cable splicing kit must be used:

Norwegian suppliers


1.2  Interface between hydrophone AQ-18 / 6ch streamer and GEODE recording system



Click to see large version:

Interface between Teledyne AQ-18 Hydrophone  / 6 channel mini-streamer and Geode Recording system (click to see large version)
Interface between Teledyne AQ-18 Hydrophone / 6 channel mini-streamer and Geode Recording system - click to see large version.


Recommended AQ-18 decoupling and wiring.
Recommended AQ-18 decoupling and wiring.

The recommended decoupling is done in the interface box shown below. The interface is also furnished with a DC/DC-converter in order to provide a clean 12 Vdc power source for the hydrophone.

Teledyne hydrophone AQ-18 interface box - clisk to enlarge.
Teledyne hydrophone AQ-18 interface box (clisk to enlarge).
6 channel mini-streamer terminals, Geode recording cable (click to enlarge).
6 channel mini-streamer terminals, Geode recording cable (click to enlarge).



2.  MINI-STREAMER 6 CHANNELS


Supplier: Sigfrance, 6 channels


Mini-streamer lay-out
Mini-streamer layout.

  • Mfr: SigFrance
  • Model: SIG 16.6x4.46
  • S/N: 08044
  • Date: 04/2008
  • Hydrophones:
    • Sensitivity: -90 dB re 1 V/uBar, +/- 1 dB
    • Frequency response: Flat +/- 1 dB over the frequency range 10 to 1000 Hz
    • Max operating depth: 80 m
    • Capacitance: 18.0 +/- 1.0 nF @ 20 deg C and 1 kHz
  • Active section:
    • Length: 46 m
    • Diameter: Inside Ø=25 mm, outside Ø=30.5 mm
    • Density: 1.05
    • Oil: 880
    • Number of channels: 6
    • Number of hydrophones per channel: 4
  • Leadin cable:
    • Length: 75 m
    • Breaking strength: 500 Kg
  • Preamplifier:
    • Number of channels: 6
    • Gain: 32 dB (=40x)
    • Bandwidth: 2 - 3000 Hz
    • Maximum voltage output: 12 V p-p
    • Current consumption: < 2 mA


3.  SEISMIC SOURCE



4.  RECORDING


4.1  Geometrics Geode

4.2  GPS for time- and position stamping of data


  • GPS: Garmin GPS 35-HVS
    GPS has been configured to only output GPGGA NMEA telegram. Link to configuration program and User Manual. The GEODE has a small quirk in that you cannot specify the NMEA telegram to record alongside seismic data. So to ensure consistency in time/positional logging the attached GPS should output only one type of NMEA telegram.

4.3  Configuration for use with UBS based GPS


If a USB based GPS should be used, there is a problem as the Geode software only accepts serial port in the Keep('COM1') to Keep('COM4') range, see screenshot below.

The USB based GPS will normally be assigned to a COM number in a higher range. So a remapping of COM port assignment need to be done.

Geode software serial setup menu
Geode software serial setup menu.

Default COM port assignment and NMEA telegram output from ordinary USB/GPS shown below.

Data from USB/GPS, default selection of telegrams.
Data from USB/GPS, default selection of telegrams.

Re-assigning COM port to fall within the 1-4 range is accomplished from Control Panel -> Hardware -> Comport -> (properties of USB/GPS port)

In advanced settings, you can force comport setting to an available number within the 1-4 range that Geode software accepts.

5.  BACKUP RECORDING SYSTEM


Ref. notes on this page.

software?

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Page last modified on October 24, 2011, at 11:05 AM
Department of Earth Science
University of Bergen
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