The paper proposes to realize a simulator for testing roaming algorithms in wireless networks. The simulator is made as a Windows application, which commands through USB the attenuators. The attenuators are related with the Access Points (APs). Proximity or the distance, of the mobile client (CL) com-pared to AP, is simulated by changing attenuation of the signal path derived from the AP's antenna. The simulator is the result of collaboration with the Embedded Wireless gmbh company, which provided the material for testing and use.