Design and implementation of an RF based Weather Station Network

AgNet is an automated weather network in North Carolina which collects surface meteorological data and land surface data. Each AgNet weather station measures Air Temperature, Relative Humidity, Wind Speed and Direction, Barometric Pressure, Solar Radiation, Photosynthetically Active Radiation, Soil Temperature, Soil Moisture and Precipitation. A data logger in each station summarizes the average values of the above parameters for every hour and stores them in its local memory. Currently the data collected over the entire day is transferred to a central server through phone lines. The data collected at the central server is then published over the Internet after quality control. Since phone based communication is not economical for real time data transfers ,other techniques such as RF Communication and Satellite based communication are being evaluated.Of these RF is more cost effective. Since RF is limited by line of sight distance, a combination of RF and internet will be ideal in terms of cost and accessebility. In this mode of communication, the data is transmitted from the weather station and received by a base station connected to the internet. The received data is then forwarded to the central server at the State Climate Office where it is archived and disseminated. To implement this technique State Climate Office is using Campbell Scientific's RF equipment. Five frequencies have been allocated by FCC for this purpose. A prototype linkage between Lake Wheeler Site, Raleigh and the State Climate Office has been established to evaluate the feasibility and dependability of the system.Methods to extend this system to the entire state will be presented.