Measurement and Evaluation of Radio Signal Attenuation by Tree Foliage: A Case Study of Federal College of Forestry Jos, Nigeria
This paper presents the measurement and evaluation of radio signal attenuation by tree foliage. Attenuation measurements were conducted using two disjoint antennas, one operating as a transmitter and the other operating as a receiver. The system was setup such that the two antennas are operated in a line-of-sight mode with random medium (in this case the foliage) positioned between the two antennas. At the transmitting section, the network interface was used to enable data to be forwarded from one network transmission out at the path to the receive antenna. The attenuation obtained was found to be dependent on many factors and parameters of the trees like geometry of measurement, (either trunk or canopy path), state of trees foliation, frequency, canopy thickness among others. The results revealed that attenuation under free space condition is insignificant at 20m and 40m either at 20m the maximum attenuation is 25dB and 28dB at 40m. The attenuation under free space increases as the distance is increase. The result also revealed that under the effect of single tree and vegetation, part of the transmitted signals are being absorbed and scattered by the tree elements such as the leaves, branches, twigs and trunks though signals are more absorbed and scattered under vegetation condition than single tree.
