According to Campbell Scientific Aust , monitoring and managing surface and ground water resources is an important task for government. Increasing pressures on water resources due to drought and climate changes have increased the importance given to monitoring of these resources, with an emphasis on groundwater sites.
In the past, the number and location of ground water sites have made data collection from these sites a labour-intensive, time consuming and an expensive task. Telemetry solutions such as cell phones allow data collection to be done remotely if coverage is adequate at the site. Costs associated with these telemetry units (both upfront and ongoing) can sometimes make these options unattractive, due to the large number of installations that must be managed.
Alternatively, using spread spectrum radios to create a network of data loggers allows a number of loggers to be accessed remotely through a single cell phone modem, keeping ongoing costs down. The routing capabilities of the Pakbus protocol provide the ability to support multiple types of network configuration.
The CR211 data logger with spread spectrum radio is a cost-effective device which offers the measurement flexibility of a Campbell Scientific Aust data logger with a license-free spread spectrum radio that allows data to be moved easily among other loggers that are within range. The RF411 spread spectrum radio can be used in conjunction with any Campbell Scientific Aust data logger or stand-alone as a repeater.
Using routing tables and neighbour lists, or appropriately written CRBasic code, the data from a network of loggers can be downloaded through a single telemetry link (such as a cell phone). This data can be moved across the Internet using Internet protocols or through standard dial-up modem configurations.
With possible radio ranges in excess of 5km (line of sight), large areas can be covered with a small amount of equipment and expenditure and this configuration is suitable for monitoring in locations with a cluster of boreholes in a localised region.