The Long Range Wide Area Network (LPWA) represents a new paradigm in the world of the Internet of Things and their potential is enormous. For the sake of simplicity of implementation, it is already used in systems for monitoring the availability of parking spaces, package delivery, smart lighting, waste management, pollution monitoring, etc. As part of this paper, the security of LoRaWAN networks as a leader of LPWA technologies will be analyzed. In doing so, the focus is placed on the finding the possibility of jamming attacks on parts of the LoRaWAN packets using simple interference techniques. Technology based on the low-cost Arduino platform indicates that adversary can easily mount such an attack simply by placing its equipment in the vicinity of gateway stations.