The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the city of Port Harcourt, Nigeria was evaluated in his work. Several network performance challenges ranging from poor network coverage to overall quality of service degradation have been recently experienced by the network users. These obvious challenges attributed to finding the efficient method for the system upgrade. Field measurements were conducted in some selected urban areas in Port Harcourt such as Aba road, Ikwerre road and Liozu roadusing Agilent tool E6474 and ZTE 302 test phone at vehicular speed. The received signal strength (RSS) was gathered from the transceiver stations of Visafone with transmitting power of 27W, mounted on a steel tower with average height of 40m and mobile height of 1.5m.The measurements were conducted within the range of 100 to 1200 meters at an interval of 100m apart. The computed pathloss exponent and the standard deviation were obtained as 3.24 and 5.11dB respectively. The propagation pathloss model for the environment of study was developed as which was compared with the existing models. The result obtained showed that the developed pathloss model was best suited for the environment