## 1 Introduction  
Wireless technologies have seen rapid development in recent years. One of the most popular applications of wireless technologies is for interpersonal communications, such as cellular phones, but in environmental monitoring and automation applications there also exists a greater potential for the use of these technologies. In some specific areas there exist target environments that are often too dangerous or inaccessible to humans or large robots and there are many challenges for deploying and maintaining wireless sensor networks (WSNs) in those unfriendly environments [1]. These facts, together with the advances in miniaturization of electronic devices have led to the emergence of specialized WSNs.  
WSNs offer improved robustness and enhanced flexibility compared with wired systems and also allow the development of applications that could not be considered possible before, such as monitoring dangerous, hazardous, unwired, or difficult to access areas and locations. An example of an efficient WSN is presented in [2] where a water environment monitoring system based on a WSN for water surveillance in an artificial lake was developed. The system is formed by several monitoring nodes linked through the ZigBee protocol, where the data from each node is gathered by a base station that sends measurements such as pH and temperature of the water to a remote monitoring center via a GPRS network.  
Over the last decade, WSNs have generated considerable enthusiasm within the networking researcher community in order to apply them to a wide range of applications, such as environmental monitoring, military target tracking, weather forecasting, home automation, intrusion detection, _etc._ [3-11]. However there are several key issues to address when selecting a suitable technology for wireless data transfer, which are determined by the application target. These include communication reliability, transmission range, data transfer rates and power consumption. WSNs are often classified in terms of transmission range, of which the standards for wireless PAN (Personal Area Network), infrared data association (IrDA), IEEE 802.15.1 (Bluetooth), and IEEE 802.15.4 (ZigBee) are the most widely used short-range technologies. Mid-range wireless local area networks (LAN) comprise IEEE 802.11b (WiFi) which is able to handle very high data rates at the expense of a higher power demand, while long-distance wireless networks include satellite communication and cellular phone systems, such as GSM/GPRS and CDMA.  
Long-range monitoring and automation applications demand new and innovative strategies and wireless network topologies in order to guarantee a minimal quality of service (QoS) while minimizing power consumption and operation costs. Long distance communication in general is more expensive and is subject to interferences; moreover in unfriendly access zones, power delivery is not available, this leads to the need for efficient use of the resources. This represents a challenge for WSNs [12] and specially collecting raw data for environmental monitoring applications can be difficult when this collecting task involves elements which are either widespread, their positions are subject to change [13] or there is a high-energy consumption involved [9]. In this way, the trend points to minimize power consumption in WSNs, permiting the system to operate with batteries and in many applications, the power is supplied with the help of the energy harvested from the environment where the device is located.  
In this paper, some challenges mentioned above for a long-range wireless mesh network for weather monitoring in unfriendly geographic conditions are contemplated. In addition, a hybrid wireless network involving the use of a free ISM band interconnected to a KU satellite link by an embedded microcontroller-based gateway is presented.