What are the power limits for license-exempt signal boosters in the UK

To be license-exempt, signal boosters must comply with Ofcom's regulations, which protect mobile networks and users from potential disruption caused by unauthorized signal boosters[3][5]. These requirements ensure that the device operates within the permissible radio frequency (RF) spectrum and does not cause harmful interference[1]. License-exempt boosters have been approved for use without a license because they meet Ofcom’s requirements[3].

Ofcom mandates that mobile signal boosters are "network-safe", meaning they should not interfere with the normal operation of mobile networks[1]. Network-safe devices include features such as automatic gain control, which prevents the booster from amplifying signals beyond the permitted levels, and automatic shut-off or reduction in gain in case of network interference[1]. Mobile signal boosters sold in the UK should also carry a CE mark, indicating that they comply with the relevant European Union directives and regulations, including the Radio Equipment Directive (RED)[1].