Geophone

GS-20DX

Feature Industry standard for cost effectiveness, quality and reliability Typical spurious response greater than 250 Hz 5% frequency and damping tolerance for minimum phase shift Waterproof Land and Marsh Cases require no potting and provide easy access to basic units Patented PCB Anchor/Takeout anchors cable with break-strength equal to or greater than the cable Full three year warranty on basic unit exclusive of high voltage, lightning or physical abuse

General Description The GS-20DX Classic Digital Grade Geophone is compatible with all field data acquisition systems. All operating parameters are confirmed with a proprietary computerized test system during the manufacturing process. Each geophone string has a brass tag with a serial number to identify its computerized test records. The GS-20DX Classic Digital Grade Geophone is the industry standard. Its rugged design with pigtail construction ensures reliability and data integrity in field conditions. * Patent No. 4594698

Specifications (At 25�� C) Natural Frequency (Fn) : 8 Hz, 10 Hz, 14 Hz Frequency Tolerance : �} 0.5 Hz �} 5 % Maintains Fn Specifications to Tilt Angle : 15��(8Hz), 20��(10Hz, 14Hz) Typical Spurious Frequency : >200 Hz(8Hz), >250 Hz (10Hz), >300 Hz (14Hz) Harmonic Distortion with Driving Velocity of 0.7 in/sec (1.8 cm/sec)P-P : <0.2% Distortion Measured at : 12 Hz (8Hz, 10Hz), 14 Hz (14Hz) Open Circuit Damping (Bo) (for all coil resistances) : 0.38 �} 10% (8Hz), 0.30 �} 10% )10Hz), 0.22 �} 10% (14Hz) Standard Coil Resistance (Rc) �} 5% : 395 Ohms Intrinsic Voltage Sensitivity �} 10% : V/in/sec : 0.70 V/cm/sec : 0.28 Optional Coil Resistances (Rc) �} 5% : 155 Ohms / 630 Ohms Intrinsic Voltage Sensitivity �} 10% : V/in/sec : 0.44 / 0.88 V/cm/sec : 0.173 / 0.346 Damping Constant at Fn (Rt Bc Fn) : 5500 for 395 Ohms , 2170 for 155 Ohms, 8760 for 630 Ohms Normalized Transduction Constant : 0.035 (sq.root Rc)V/in/sec (.0138 (sq.root Rc)V/cm/sec)) Moving Mass �} .5g : 11g Case to Coil Motion P-P : Min : 0.8 mm (0.32 in) Max : 1.5 mm (0.60 in) Operating Temperature Range (��C) : -45�� to +100�� Dimensions (less terminals*) : Height : 3.30 cm (1.30 in) Diameter : 2.54 cm (1.00) Weight : 87.3 g (3.08 oz.) *terminal height is .16 inches Chart for Seismic Detector Response Curve Output VS. Frequency. Cases Available PC-801 LP Land Case, PC-801 LPC Land Case, PC-901 Marsh Case

GS-20DM GS-20DM

General Description The GS-20DM Small Digital Grade Geophone fills the need for reducing the weight and volume of geophone strings. Through a design that includes total internal damping and the use of smaller and stronger magnets, the weight and size of the GS-20DM have been reduced by approximately 50% while maintaining the same performance characteristics of the traditional larger geophones. The GS-20DM header has the patented and ultrasonically welded PCB for strong cable anchoring and reliable electrical contact. This design, with rotating coil construction, silver plated contacts and gold plated springs, assures long field life and parameter stability. The geophone operating parameters are checked and confirmed with a proprietary computerized test system during the manufacturing process. Each geophone string has a brass tag with a serial number to identify its computerized test records. The GS-20DM basic unit has a two year warranty. Cases Available The GS-20DM has the industry's widest choice of waterproof horizontal and vertical cases, land and marsh cases, as well as cases for use with 2D and 3D configurations.

Specifications (At 25�� C) Natural Frequency (Fn) �} 5% : 10 Hz, 14 Hz, 28 Hz, 40 Hz Maintains Fn Specifications to Tilt Angle of : 20��(10Hz, 14Hz), 90��(28hz, 40Hz) Typical Spurious Frequency : >300 Hz (10Hz), >400 Hz (14Hz), >600 Hz (28Hz), >850 Hz (40Hz) Harmonic Distortion with Driving Velocity of 0.7 in/sec (1.8 cm/sec)P-P : <0.2% Distortion Measured at : 12 Hz (10Hz), 14 Hz (14Hz), 28 Hz (28Hz), 40 Hz (40Hz) Open Circuit Damping (Bo) (for all coil resistances) : 0.70 (10Hz, 14Hz), 0.60 (28Hz), 0.42 (40Hz) Standard Coil Resistance (Rc) �} 5% : 280 ohms (10Hz), 240 ohms (14Hz), 270 ohms (28Hz, 40Hz) Intrinsic Voltage Sensitivity �} 7% : V/in/sec : 0.500 (10Hz), 0.450 (14Hz), 0.384 (28Hz), 0.384 (40Hz) V/cm/sec : 0.197 (10Hz), 0.177 (14Hz), 0.151 (28Hz), 0.151 (40Hz) Optional Coil Resistances (Rc) �} 5% : 65 / 435 (10Hz), 56 (14Hz), 110 (28Hz, 40Hz) Damping Constant : 1.37 Rc (10Hz), 0.95 Rc (14Hz), 0.43 Rc (28Hz), 0.30 Rc (40Hz) Normalized Transduction Constant : V/in/sec : 0.030 (sq. root Rc) (10Hz), 0.029 (sq. root Rc) (14Hz), 0.023 (sq. root Rc) (28Hz), 0.023 (sq. root Rc) (40Hz) V/cm/sec : 0.012 (sq. root Rc) (10Hz), 0.011 (sq. root Rc) (14Hz), 0.009 (sq. root Rc) (28Hz), 0.009 (sq. root Rc) (40Hz) Moving Mass �} 5% : 8.0g(.28 oz.) (10Hz), 7.8g(.28 oz.) (14Hz), 5.6g(.20 oz.) (28Hz), 5.6g(.20 oz.) (40Hz) Case to Coil Motion P-P : Min : 1 mm (.04 in) Max : 2 mm (.08 in) Operating Temperature Range (��C) : - 45�� to +100�� Dimensions (less terminals*) : Height : 2.64 cm (1.04 in) Diameter : 2.22 cm (.875) Weight : 43 g (1.5 oz.) Specifications are subject to change without notice. Chart for Seismic Detector Response Curve Output VS. Frequency. Cases Available PC-801 LP Land Case. PC-801 LPC Land Case, PC-901 Marsh Case Specifications are subject to change without notice.