Be aware that Zigbee is a transmission standard, rather than a frequency allocation and while it pops up both at 2.4GHz, and shares that frequency with Bluetooth, WiFi and Microwave ovens, it also pops up in the 868 MHz band in the UK, and it is this variant that is more common for smart metering. This band is snuck in the gap between the top of the TV broadcast band, and the GSM 900 MHz band used for mobile phones.
Be aware that Zigbee is a transmission standard, rather than a frequency allocation and while it pops up both at 2.4GHz, and shares that frequency with Bluetooth, WiFi and Microwave ovens, it also pops up in the 868 MHz band in the UK, and it is this variant that is more common for smart metering. This band is snuck in the gap between the top of the TV broadcast band, and the GSM 900 MHz band used for mobile phones.
