This paper presents a wide area medium frequency loosely coupled magnetic energy harvesting system with power delivery and network synchronisation for remote sensors, intended for agricultural and industrial environments. Intended for situations with poor service access, power is supplied from a source via a large area loop. Receiver nodes may use ferrite cored coils for good efficiency with modest volume. Transmission of low bandwidth network synchronisation data permits very low operational duty cycle with the need for real time clocks or wake up receivers and their associated power drain. As a key enabler for the system, a full custom energy harvester and QPSK data demodulator IC has been designed and fabricated in a commercial 180nm CMOS technology. The IC occupies 0.54mm2 and can deliver 10.3µW at 3V to an external battery or capacitor. With standard MOS device thresholds the rectifier can start from cold with only 250mV peak from the antenna loop, and the battery charge output is delivered with 330mV peak input. Results are presented from laboratory evaluation and from preliminary measurements in the field with a 10m x 10m loop driven at 800kHz.