TETRA is the term used to describe the technology known as Terrestrial Trunked Radio. It is the European standard digital mobile radio communication system. TETRA has primarily been developed to enable the deployment of secure, digital PMR (Professional Mobile Radio) services required by the public safety and emergency services (police, fire and paramedics). The TETRA system is specified to work within the VHF and UHF bands (150 MHz to 900 MHz) [Chadwick, 2003], and operates most often at frequencies around 400 MHz. The lower frequency means that TETRA is less vulnerable to interference, which is a vital aspect of communications for the emergency services. The system makes it possible to offer complete coverage for the emergency services. One of the TETRA features is that the signal is transmitted in bursts that repeat. The result is a power modulation of some of the RF signal at a frequency of 17,6 Hz (times pr. second) [NRPB, 2001]. This pulsing has led to concerns about its effect on health. Since this pulsing only occurs for transmission from TETRA handset and not from the base stations, most concerns is related to the health effect on the users of TETRA handset.