A renewable energy, in particular solar photovoltaic, monitoring system for monitoring a renewable energy generation device mounted on or adjacent to a building, comprising: a device monitor coupled to a renewable energy generation device to monitor said renewable energy generation device and generate monitoring data defining a status of said renewable energy generation device, said device monitor wirelessly communicating said monitoring data to a gateway using a wireless communications link, said gateway receiving said monitoring data from said device monitor and communicating said monitoring data to a monitoring station; and a wireless repeater providing said communications link between said device monitor and said gateway, wherein said wireless repeater comprises: a wireless transceiver module (13, 15); a plurality of spaced apart antennas (12, 14) coupled to said wireless transceiver module; at least one antenna interface having one or more of said plurality of spaced apart antennas electrically coupled thereto; wherein said wireless transceiver module (13, 15) is coupled to said at least one antenna interface, said wireless transceiver module comprising data receiving and transmission means to receive said monitoring data from at least one of said plurality of spaced apart antennas and to transmit said monitoring data using one or more other of said plurality of spaced apart antennas, and a processing element coupled to said data receiving and transmission means to process said monitoring data received and transmitted from said one or more of said plurality of antennas; and wherein a first of said plurality of spaced apart antennas is located proximally to said device monitor and a second of said plurality of spaced apart antennas is located proximally to said gateway. a device monitor coupled to a renewable energy generation device to monitor said renewable energy generation device and generate monitoring data defining a status of said renewable energy generation device, said device monitor wirelessly communicating said monitoring data to a gateway using a wireless communications link, said gateway receiving said monitoring data from said device monitor and communicating said monitoring data to a monitoring station; and a wireless repeater providing said communications link between said device monitor and said gateway, wherein said wireless repeater comprises: a wireless transceiver module (13, 15); a plurality of spaced apart antennas (12, 14) coupled to said wireless transceiver module; at least one antenna interface having one or more of said plurality of spaced apart antennas electrically coupled thereto; wherein said wireless transceiver module (13, 15) is coupled to said at least one antenna interface, said wireless transceiver module comprising data receiving and transmission means to receive said monitoring data from at least one of said plurality of spaced apart antennas and to transmit said monitoring data using one or more other of said plurality of spaced apart antennas, and a processing element coupled to said data receiving and transmission means to process said monitoring data received and transmitted from said one or more of said plurality of antennas; and wherein a first of said plurality of spaced apart antennas is located proximally to said device monitor and a second of said plurality of spaced apart antennas is located proximally to said gateway. a wireless transceiver module (13, 15); a plurality of spaced apart antennas (12, 14) coupled to said wireless transceiver module; at least one antenna interface having one or more of said plurality of spaced apart antennas electrically coupled thereto; wherein said wireless transceiver module (13, 15) is coupled to said at least one antenna interface, said wireless transceiver module comprising data receiving and transmission means to receive said monitoring data from at least one of said plurality of spaced apart antennas and to transmit said monitoring data using one or more other of said plurality of spaced apart antennas, and a processing element coupled to said data receiving and transmission means to process said monitoring data received and transmitted from said one or more of said plurality of antennas; and wherein a first of said plurality of spaced apart antennas is located proximally to said device monitor and a second of said plurality of spaced apart antennas is located proximally to said gateway.