New and Used Geophones for Sale

Last Updated: 8/29/2016

If you have any Geophones for sale please contact us

New Geophones:

Used Geophones:

More Information:


Baoding Longet Equipments 4.5 Hz 3-Component LGT Sensor

Assembly Photos

More Information and Cost:

These are new 3-component 4.5Hz Geophones made by Baoding Longet Equipments Co., Ltd in China. The datasheet for the LGT sensor can be viewed here. The coil resistance is 375 ohms and has an undamped output voltage of 28.8V/m/s or .731V/in/s. The manufacture does not supply the resistance needed for a damping of .7 and the output voltage at that damping value. We have tested several units and a 14K resistor produces a damping around 70% or .7.    

Cost and Availability:  $170.00 each for the unwired sensor. Add $35.00 for the wired version. This price includes the three sensor elements, case, spikes and mounting hardware. This item is in-stock.

Wired Version for PSN-ADC24 Digitizer

Wired Version:

There are two versions of the wire sensor. One is for our single-ended 1 to 4 Channel Amp/Filter and 16 Bit Digitizer boards.  This version will come with three 6-foot (~1.8m) shielded audio cables with a molded RCA plug. The other version is for our differential input 24-Bit Digitizer board. For this version we use 10 feet ( ~3 m) of shielded Ethernet Network cable with a standard 2.77mm D-Sub DB-15 male connector soldered to the end of the wire. See photo above. Other lengths of wire are possible. Please contact us for a quotation.

D-Sub DB-15 Connector Pinout for the PSN-ADC24 Digitizer board:

  • Pin 1 - Solid Orange Wire = Vertical Sensor Coil + Signal
  • Pin 2 - Orange/White Wire = Vertical Sensor Coil - Signal
  • Pin 3 - Solid Green Wire = Horizontal Sensor Coil #1 + Signal
  • Pin 4 - Green/White Wire = Horizontal Sensor Coil #1 - Signal
  • Pin 5 - Solid Blue Wire = Horizontal Sensor Coil #2 + Signal
  • Pin 6 - Blue/White Wire = Horizontal Sensor Coil #2 - Signal
  • Pin 11 = Ground for Foiled Shielded and Drain wire. Not connected inside the sensor.

The wired version does not come waterproofed. The user will need to do this themselves using some sealant like RTV in both ends of the sensor.

Sensor channel orientation and additional DB15 Pinout information can be found here

Here are some test measurements performed on one of the Longet LGT 4.5Hz sensor. Of note is the No Load Transducer Gain of the sensor. The manufactures data sheet lists the output at 0.288 V/cm/s and Micheal testing (highlighted in yellow) showed the output to be very close to that number. His testing produced the following output voltages: X=0.287, Y=0.287 and Z=0.277 V/cm/s  

Please read this if you are planning to use a geophone to record earthquakes. If you would like to place an order please see our  How to Order Web page.


Dynamic Technologies DT20DX 4.5 Hz Vertical Sensor

  

More Information and Cost:

These are new vertical only 4.5Hz Geophones made by Dynamic Technologies and sold by R.T Clark. The datasheet for the sensor can be viewed here. The coil resistance is 395 ohms and have an output voltage of 23.4V/m/s or .594V/in/s at a damping of .7. Unfortunately the datasheet does not give the resistance of the damping or shunt resistor used in the calibration of the senor. We assume it's around 3K like the L15B sensor below.

Cost and Availability:  This item is not in-stock

The wired version does not come waterproofed. The user will need to do this themselves using some sealant like RTV in both ends of the sensor.

Please read this if you are planning to use a geophone to record earthquakes. If you would like to place an order please see our  How to Order Web page.


Mark Products 4.5 Hz 3-Component L15B Sensor

Specifications and Sensitivity Plot

More Information and Cost: 

These sensor are removed from a string of 6 sensors. The sensors are used but in good condition. Here are two GIF images of earthquakes recorded with this sensor: Ml4.4 Vertical Component and Md2.7 N-S Component.

We are selling this sensor either "as is" or wired and tested. The "as is" units are removed from the string, you will need to open them and do the re-wiring yourself. The wired units are opened and three wires, with RCA type connectors at each end, are soldered to the geophone elements. We then verify that each element is working properly. The wired units can be directly plugged into my Seismic Amplifier / Filter Board. Please Note: Since we need to open up the wired units they will no longer be waterproof. 

Cost and Availability: This item is not in-stock.  See the Baoding Longet sensor above for a replacement.


GeoSpace HS 10-1 1 Hz Vertical Sensor

 

The coil resistance is 400 ohms.

GeoSpace Web page for the HS 10

This item is not in-stock.

Please read this if you are planning to use a geophone to record earthquakes. If you would like to place an order please see the  How to Order Web page.


Mark Products L10B 4.5 Hz Vertical Sensor

 

The coil resistance is about 220 ohms.

This item is not in-stock. 


Recording Earthquake using Geophones:

Geophones, with periods around 1 to 2 Hz, are short period devices designed to record local or large regional events. The higher frequency sensors (4.5 Hz and above) are mainly used for oil and geological studies. Geophones with periods around 4.5 Hz  will record local events, see GIF images above, but they are not designed for this purpose. Short period sensors will not record distant (teleseismic) events very well, if at all. Depending on your location they may pick up the P wave of large teleseismic events. If you live in an area where you will only be recording teleseismic events you should not consider using a short period device. To record all of the different waves produced by a teleseismic event you will need a long period device like a Lehman, Shackleford-Gundersen, or broadband sensor. Construction notes on building a vertical broadband sensor can be found here.

More information about geophones can be found here and on Wikipedia.


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Larry Cochrane - www.seismicnet.com/contact.html