The 24GHz spectrum is a licence free band. However, its use is limited as per the guidelines from OFCOM / ETSI.
The spectrum operating frequency range is 24.15 – 24.25GHz. The OFCOM/ETSI standard reference is IR2030/1/24 and EN300 440 (2013/752/EU band No. 70a).
The maximum EIRP (Effective Isotropic Radiated Power) is 20dBm / 100mW.
EIRP (dBm) = Output Power (dBm) + Antenna Gain (dBi)