This paper describes a Spectrum observatory (SO) performed outdoor in two locations in Algeria and highlights the importance of the SO in the improvement
of Spectrum Management in cognitive radio networks. These measurements were achieved in conjunction with the ANF (Agence Nationale des Fréquences), between January and February 2020. It surveys second, third, and fourth-generation mobile networks and DVB-T frequency bands. A comparative study of two measurement campaigns (in urban & rural) that were carried out via identical setup and equipment is presented. Some major short-duration measurement campaigns are cited and summarized for the state-of-the-art. Additionally, Different statistics are imputed and 3D graphics of the Spectrum occupancy are plotted to highlight the Spectrum opportunities in this region. This work aims to analyze the radio environment in Algeria and identify frequency bands that could be invested for the integration of new wireless systems and Cognitive Radio opportunistic networks. The evaluation of measurement results reveals low resource occupation, lower than 30.27%, for Constantine and 8.43% for Ouargla. The final part of the study inspects the effect of specific SO features upon the Management strategy parameters’ selection. Via a meaningful SO, an efficient Spectrum Management strategy can achieve the safest users access to the idlest channels with the minimum costs and risks.