PART6 RF WAVES

11.11.2009

ANNEX -

2

2. Exposure sources

The exposure to an individual caused by any single RF source is strongly dependent on the distance

between the source and the individual, the source output power and duration of RF transmission.

Therefore, regarding exposure there are two main types of devices; small devices used close to the

individual (hand-held and/or body-worn) and fixed transmitters. Exposure caused by devices used

close to the individual is localised and usually occasional, since RF transmission shuts down while

not in use, though exposure to RF can be near the ICNIRP exposure limits when such devices are in

use. Fixed transmitters often use high output powers and typically transmit RF continuously. Recommended

exposure limits can therefore be exceeded in close proximity to such sources. Fixed

transmitters are, however, usually installed in places where the general public does not have access,

such that the typical exposure caused by fixed transmitters is very low. Table 1 and 2 list some properties

of the most common RF technologies in use.

Table 2. An overview of commonly used fixed radio transmitters including information regarding

frequency and output power

Technology Related acronyms Frequency

range

(MHz)

Typical output

power

Typical power density

mW/m

2

GSM 900 900 < 0.1

GSM 1800 (former

DCS 1800)

1800 < 0.1

Mobile phone

base stations

UMTS (also 3G) 2150

20 W

< 0.1

TV broadcasts

(digital)

DVB-T 500 - 900 15 kW

< 0.01

Voice radio

broadcasts

VHF, FM-radio 87-108 50 kW

< 0.001

WLAN (also WiFi) 2450 100 mW

3G

♠

WiMAX 3500 1 W

Wireless internet

connections

(base stations)

Flash-OFDM

(@450 in Finland)

450 up to 20 W

Cordless phone

(fixed part)

DECT 1900 10 mW (single

phone

system)

Professional

mobile radio

(police etc.)

TETRA 400 up to 100 W

♠

3G is based on regular mobile phone base stations (see above)

2.1 Handheld and body worn devices

The highest output powers of hand-held/ body worn devices (e.g., mobile phones, laptops incorporating

a WLAN card or other wireless network adapter) are typically in the 100–500 mW range. The

output power is therefore relatively low, though a large fraction can be absorbed by the user leading

to exposures of the same order of magnitude as recommended exposure limits for localised exposure

to the general public (

small due to the low output power of such devices. In addition, such devices are typically used onlySAR limit of 2 W/kg). However, average whole-body exposures will always be