DO NOT mount gateways inside of a metal enclosure.
Metal enclosures will significantly attenuate RF signals and can severely degrade wireless performance, range, and reliability.
Mounting gateways inside a non-metallic enclosure is also not recommended.
The impact on signal strength and overall system performance is unknown and may vary based on enclosure material, thickness, size, and internal layout. Performance degradation is especially likely if additional electronics or hardware are installed inside the enclosure alongside the gateway.
For optimal performance, the gateway should be mounted in an open environment with a clear RF path to the sensors.