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28Hz Reinforced Land Case Geohpone for P Wave and S Wave

28Hz (ST-20DX,28Hz) reinforced land case geophone in vertical direction (P wave) and horizontal direction (S wave) are available, which are suitable for deep seismic exploration, advance prediction, natural seismic survey, pulsating microseismic survey of bridges, dams, highways and railways, safety monitoring, engineering pulse measurement and other vibration analysis.

● Good parameter consistency.

● Firm mechanism structure.

● Good sealability.

● Suitable for multi-wave component seismic data acquisition.

● Different type of geophone cases which are suitable for land,desert, snow, marsh and transition zone respectively.

●3-year limited warranty on basic element exclusive of high voltage, lightening or physical abuse.

We supply 28hz geophone coil, geophone element, geophone sensor, single geophone and geophone array with KCK connector, KCL connector, 408 connector, Kooter connector, MP16 connector, Split spring connector and Mueller clip connector optional as the lead connector. Lead wires from O.D 4.6mm to O.D 7.8mm available.

Click here and download data sheet of 28hz geophones or contact us to get special discounts.


For any inquiries, please contact with our Marketing Team at or Supporting Team at

Type ST-28N

(Equivalent to SM-4,28hz)

ST-20DX 28hz

(Equivalent to GS-20DX,28hz)

Natural frequency ( Hz ) 28 ± 5% 28±5%
Open circuit damping 0.6 0.22
Damping with Shunt Resistor 0.634 ± 5% 0.552±5%
Open Circuit Intrinsic Voltage Sensitivity(V/m/s) 31.0 39.0
Sensitivity with Shunt Resistor(V/m/s) 29.5 ± 5% 28.0±5%
Coil Resistance (ohms) 385 ± 5% 395±5%
Harmonic Distortion ( % ) <0.2 ≤0.2
Typical Spurious Frequency ( Hz ) ≧300 ≥350
Moving Mass ( g ) 10.2 11.0
Max.coil excursion p-p (mm) 1.6 1.5
Max.tilt angle 20º 20º
Element Diameter (mm) 26 25.4
Element Height (mm) 32 33.5
Element Weight (g) 80 87.0
Operating Temperature(℃) -40℃ to + 100℃ –45℃ to + 100℃
Warranty Period 3 years 3 years
● All parameters specified herein are rated at a temperature 20℃±2℃.
● 3-year limited warranty on basic element exclusive of high voltage, lightening or physical abuse.


– Other type of geophones are also available: SM-4 Equivalent, SM-6 Equivalent, SM-24 Equivalent, SG10 Equivalent, GS-20DX Equivalent, GS-32CT Equivalent, GS ONE Equivalent, 1Hz, 2Hz, 2.5Hz, 3Hz, 4Hz, 4.5Hz, 5Hz,8Hz, 10Hz, 14Hz, 15Hz, 28Hz, 30Hz, 38Hz, 40Hz, 60Hz,80Hz and 100Hz.

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