GEM System Specifications Features and Capabilities

Core Capabilities-Flexibility with Value

GEM’s product families are carefully designed to offer you a range of non-overlapping capabilities so that you can select the ideal system for your application, sensitivity needs, budget, upgrade pathway, etc.

The following table shows a summary of Core Capabilities for the QuickTracker™ , Overhauser, SuperSenser™ and SuperGrad™ technologies. (To see how each of these technologies relates to your survey needs, you may want to have a quick look at the Application Configurator).

Core capabilities are organized in terms of the criteria that deliver our customers the most flexibility and value, namely:

Performance
Operating Mode
Data and Input/Output
Mechanical/Power
Maintenance and Support
Environmental
Shipped Component

After comparing the capabilities for each system, you may also want to refer to our information on Options, which includes:

Building Blocks
Sensor Options
GPS Options
GPS Navigation Options
Software Solutions

To review information on options, GEM System Options.

GEM Core Capabilities

Product Family	Proton	Overhauser	Potassium	SuperGrad
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Reading Mode	Slow	Walk (includes Slow sampling)	Super Fast (includes Fast and partial Walk sampling)	Super Fast (includes Fast sampling)
Performance
Sensitivity	0.15nT @ 1 reading per sec 0.05nT @ 1 reading every 4 sec	Standard GSM 19 0.022 nT @ 1 Hz GSM 19PRO 0.015 nT @ 1 Hz	0.0002 nT @ 1Hz	0.02pT @ 1Hz
Absolute accuracy over temperature range (plus/minus nT)	0.1 nT @ 1 Hz	0.1 nT	0.1 nT	0.1 nT
Dynamic range (nT)	20,000 to 120,000	20,000 to 120,000	15,000 to 120,000	20,000 to 120,000
Gradient tolerance (nT/m)	> 7,000	up to 10,000	50,000	2000
Counter resolution	0.01 nT	0.01 nT	0.0001 nT	0.001 pT @ 20Hz
Cycle time (seconds)	60+, 5, 4, 3, 2, 1, 0.5	60, 5, 3, 2, 1, 0.5, 0.2	1, 0.2, 0.1, 0.05	1, 0.5, 0.25, 0.2, 0.1, 0.05
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Operating Mode
Programmable base station	Yes	Yes	Yes	No
Stationary (time, date and reading storage)	60 to 3 seconds	60 to 1 seconds	1 to 0.05 seconds	1 to 0.05 seconds
Mobile (coordinates, time, date and reading stored automatically)	3 sec minimum	60 to 0.2 seconds	No	1 to 0.05 seconds
Walking (time, date and reading stored automatically. Coordinates assigned at picket)	0.5,1 or 2 seconds	0.5,1 or 2 seconds	1 to 0.05 seconds	No
Remote control (optional)	RS-232	RS-232	RS-232	RS-232
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Data and Input/Output
Standard Memory (4 Mbytes)	Yes	Yes	Yes	Dumps direct to computer
Readings (base station)	5.3M	5.3M	8.3M	Continuous reading
Readings (mobile)	1.4M	1.4M	N/A	Continuous reading
Readings (gradiometer)	1.2M	1.2M	2.4M	Continuous reading
Readings (walking mag)	2.6M	2.6M	3.3M	Continuous reading
Data transfer (115 Kbytes)	Yes	Yes	Yes	Yes
Analog output (optional)	Yes	Yes	Yes	Yes
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Maintenance and Support
Expandable memory (4 Mbyte increments)	32 Mbytes	32 Mbytes	32 Mbytes	32 Mbytes
Internet firmware upgrades	Yes	Yes	Yes	Yes
Upgradeable to higher version or product family	Yes	Yes	No	No
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Mechanical/Power
Batteries	1 internal	1 internal	1 internal and 2 external	N/A
Battery belt	176 x 78 x 125	176 x 78 x 125	267 x 178 x 76 cm	N/A
Battery weight	0.6 kg	0.6 kg	3.9 kg	N/A
Console dimensions	223 x 69 x 240 mm	223 x 69 x 240 mm	223 x 69 x 240 mm	483 x 89 x 406 mm
Console weight	2.1 kg	2.1 kg	2.1 kg	4.5 kg
Sensor head dimensions	75 mm dia. X 140 mm length	75 mm dia. X 175 mm length	89 mm dia. and 152 mm length	Standard Sensor: 20.3 x 10.2 cm (8 x 4 dia. in) Larger Sensor: 26.3 x 23dia cm (12 x 8.25 dia. in)
Sensor head weight	2.0 kg	1.0 kg	1.37 kg	Standard Sensor: 3.0 kg / 6.6 lb Larger Sensor: 6.0 kg (13.2 lb)
Sensor angle	N/A	N/A	35 degrees between sensor head axis and magnetic field vector	45 degrees plus/minus 35 degrees off magnetic field direction
Electronics dimensions	N/A	N/A	306 x 85 x 750 mm	100 x 50 x 50 mm
Electronics weight	N/A	N/A	1.6 kg	1.0 kg
System warm-up time	N/A	N/A	<10 minutes @ 20 degrees C	2 hours @ 20 degrees C
Power supply	12 V DC	12 V DC	22 to 32 V DC	22 to 60 V DC
Power start-up	N/A	N/A	25W dropping to 8 W
Power consumption	12 watt-seconds per reading	2 watt-seconds per reading	8 watt @ 20 degrees C	80 W avg., 250 W max.
Console power requirements	12 V 2.2 Ah battery	12 V 2.2 Ah battery	12 V 2.2 Ah plus 24 V 7.2 Ah batteries	28 V 6 A DC power supply
Staff assembly	2240 mm length	2240 mm length	760 mm length	N/A
Staff weight	1.0 kg	1.0 kg	1.2 kg	N/A
VLF sensor	160 x 150 x 150 mm	160 x 150 x 150 mm	160 x 150 x 150 mm	N/A
VLF sensor weight	1.3 kg	1.3 kg	1.3 kg	N/A
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Environmental
Operating temperature	minus 40 to 50 degrees C	minus 40 to 50 degrees C	minus 40 to 55 degrees C	minus 40 to 55 degrees C
Humidity	0 to 100% splashproof components	0 to 100% splashproof components	0 to 100% splashproof components	1 to 100% splashproof sensors; console requires protected mounting
Temperature storage	minus 70 to 55 degrees C	minus 70 to 55 degrees C	minus 70 to 55 degrees C	minus 70 to 55 degrees C
Model	GSM-19T	GSM-19W	GSMP-35	GSMP-20
Shipped Components
Batteries	Yes	Yes	Yes	No
Battery charger	Yes	Yes	Yes	No
Cable	1.2 m sensor cable, RS-232 cable	1.2 m sensor cable, RS-232 cable	2.5 to 5 m between sensor/drive and 1 to 100 m between electronics/signal processor	User specified
Console	Yes	Yes	Yes	Yes
GEMLink software	Yes	Yes	Yes	Yes
Harness for console	Yes	Yes	Yes	No
Manual	Yes	Yes	Yes	Yes
Sensor	Yes	Yes	Yes	Yes
Shipping case	Yes	Yes	Yes	No