73
Recommended separation distances between portable and mobile
RF communications equipment and the SD 270 Audiometer
The SD 270 Audiometer is intended for use in an electromagnetic envi-
ronment in which radiated RF disturbances are controlled. The customer
or the user of the SD 270 Audiometer can help prevent electromagnetic
interference by maintaining a minimum distance between portable and
mobile RF communications equipment (transmitters) and the SD 270
Audiometer as recommended below, according to the maximum output
power of the communications equipment.
Rated maxi-
mum output
power of trans-
mitter
W
Separation distance according to frequency of
transmitter
m
150 kHz to 80
MHz
d = 1.2√P
80 MHz to 800
MHz
d = 1.2√P
800 MHz to 2.5
GHz
d = 2.3√P
0.01
0.12
0.12
0.23
0.1
0.38
0.38
0.73
1
1.2
1.2
2.3
10
3.8
3.8
7.3
100
12
12
23
For transmitters rated at a maximum output power not listed above, the
recommended separation distance d in metres (m) can be estimated
using the equation applicable to the frequency of the transmitter, where
P is the maximum output power rating of the transmitter in Watts (W)
according to the transmitter manufacturer.
NOTE 1: At 80MHz and 800MHz, the separation distance for the higher
frequency range applies.
NOTE 2: These guidelines may not apply in all situations. Electromagne-
tic propagation is affected by absorption and reflection from structures,
objects and people.