Handy Tech
Elektronik GmbH
Easy Braille
Appendix
Page 39
a
Field strengths from fixed transmitters, such as base stations for radio (cellular/cordless) telephones
and land mobile radios, amateur radio, AM and FM radio broadcast and TV broadcast cannot be
predicted theoretically with accuracy. To assess the electromagnetic environment due to fixed RF
transmitters, an electromagnetic site survey should be considered. If the measured field strength in
the location in which the Braille display is used exceeds the applicable RF compliance level above,
the Braille display should be observed to verify normal operation. If abnormal performance is
observed, additional measures may be necessary, such as re-orienting or relocating the Braille
display.
b
Over the frequency range 150 kHz to 80 MHz, field strengths should be less than 3 V/m.
Recommended separation distances between portable and mobile
RF communications equipment and the Braille display
Recommended separation distances between
portable and mobile RF communications equipment and the Braille display
The Braille display is intended for use in an electromagnetic environment in which radiated RF
disturbances are controlled. The customer or the user of the Braille display can help prevent
electromagnetic interference by maintaining a minimum distance between portable and mobile RF
communications equipment (transmitters) and the Braille display as recommended below,
according to the maximum output power of the communications equipment.
Rated maximum
output power of
transmitter
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 80 MHz and 800 MHz, the separation distance fort he higher frequency range applies.
NOTE 2: These guidelines may not apply in all situations. Electromagnetic propagation is affected by
absorption and reflection from structures, objects and people.
