We detail the hardware and software used to build a test-bed for a sustainable WiFi network serving a mission-critical application. A power management scheme is introduced that is based on a Markov Chain model, together with details of its practical implementation and realization on the solar-powered WiFi network. The power management scheme consists of three main modules: an event trigger, a monitor and a decision module. The event trigger module decides if it is adequate to transition from one state to another in terms of performance and power. The monitor module processes the user request arrival times, number of jobs in the access point queue, service time and the time elapsed since the last time the access point was in the current state. The decision module utilizes a Markov Chain where the different states are the access point antenna power levels from 0-4 W. The decisions are made based on an event in all states excluding the idle state. Off-the-shelf devices are used to implement the test-bed. The software used is open source and in-house firmware.