Radio spectrum is a finite resource and, in many cases, demand outstrips supply. So, in order to manage this demand and ensure certainty of transmission, licences are required for particular frequencies. Ofcom manages the Isle of Man's radio spectrum and issues around 30 different kinds of Wireless Telegraphy Act licence. If you wish to use licensable radio frequencies on the Isle of Man, you should apply to Ofcom, who will then consult with the Authority, as other licenses may be required.
Not all spectrum or equipment is licensable however. Certain equipment or technologies are licence-exempt - i.e. where their use is not likely to involve any undue interference to other legitimate use of radio spectrum, no Wireless Telegraphy Act licence is required. Ofcom's website lists all licence exempt devices.
You don't need to hold a Wireless Telegraphy (WT) Act licence in order to operate Citizens 'Band Radio equipment. For more details visit the Ofcom website.
The radio spectrum used for Wi-Fi, Bluetooth and cordless phones is classed as licence exempt.
Licences to operate wireless microphones at outside broadcasts, concerts etc falls under the Programme Making and Special Events (PMSE) class of licences.
If you're operating on the Isle of Man, you will require a licence which can be obtained from Ofcom.