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A GCMS sensor site, also called a remote monitoring station, consists of the following primary components:
- Three high-sensitivity induction coils, each with preamplifiers, in a weatherproof enclosure
- Filter boards, acquisition and Wi-Fi systems, all in a weatherproof enclosure
- Solar panels with a regulator and battery
- GPS antenna
* A key element in the monitoring process is the base station, which is situated in a strategic location at an optimal distance of 500 meters from the sensor site and is equipped with a Wi-Fi receiver and antenna.
Click to view GCI’s Sensor Site Map 2012.
Site Selection Criteria
Given the extreme sensitivity of the sensors, GCMS sensor sites must be carefully selected. The following are the main criteria for the sites:
Wind – Even subtle movements of these sensors can influence the measurements. When possible, sites must be protected from wind.
Traffic – The sensor site must be located at least 300 meters from moderately used roads and 1,000 meters from heavily used roads.
Ferromagnetic materials – Iron-based objects such as metal fence posts cannot be located within 7 meters of a sensor.
Temperature – Sensor equipment is designed to withstand extreme temperature conditions, but it is best to locate it where there are minimal temperature extremes.
Solar radiation – The solar panels must have unobstructed exposure to direct sunlight. They must be no closer than 10 meters and no farther than 100 meters from the sensors.
Power lines – The sensor site must be a minimum of 400 meters from the nearest power line. The greater the distance away from power lines, the better the signal quality.
Line of sight – There must be a clear line of sight between a base station and a sensor site. Although the ideal distance between a base station and sensor site is about 500 meters, the distance can actually be up to 10 kilometers, but this would require additional equipment.
Internet access – A base station must have high-speed Internet access.
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