Today, there is a very large number of networks. We divide the networks into two basic groups: wireless and wired. In this final paper, the topic of wireless networks is discussed and the threat of jamming of the wireless network signal. The aim of this final paper is to explain the concept of jamming at different frequencies, the methods and devices that are being used for the purpose of jamming. The matter of subject are basic principles and types of intentionall and unintentionall jamming. For the purpose of ethical interference, or for the purpose of protection, there are many devices being used nowadays, since it has become a top priority in many parts of the world. Types of jamming systems that are being used in that purpose are military convoy protection jamming systems, VIP convoy protection systems, portable/tactical jammers and stationary jamming systems. As an experiment for demonstrating simplicity and availability, jamming was implemented using software defined radio. With software defined radio, frequency spectrum on which the radio station was broadcast was analyzed and a certain radio station was selected, whose signal quality was disturbed by transmitting the interference signal with softwer defined radio.