User's Manual

5
To calculate safe distance:
   
  
mitExposureLi
nAntennaGaiDutyCycleowerConductedP
MPE D
 4

Where:
MPED is Maximum Permissible Exposure Distance or safe distance in cm;
owerConductedP
is the power delivered to antenna input in mW;
m itExposureLi
is a limit for General Population/ Uncontrolled exposure in mW/cm
2
All quantities are calculated in linear or numeric quantities.
Duty cycle is set using packet sizes for master and slave. Packet sizes are set in the radio
Network Configuration Menu. At power up and with no data transmitting, the radios
will transmit or beacon with a duty cycle of 6 to 10% depending upon modulation
setting.
FCC MPE Calculation:
Antenna: 11 dBi (757-758 MHz band)
6 dBi (787-788 MHz band)
For 300-1500 MHz single transmitters (General use):
Freq
MHz
EUT
Power
dBm
EUT
Power
mW
Cable
Loss
dB
Ant
Gain
dBm
Power
at Ant
dBm
EIRP mW
Power
Density (S)
at 20 cm
mW/cm2
MPE Limit
at 20 cm
mW/cm2
757.5
40.4
10964.8
0
11
40.4
138038.43
333
27.462
0.505
787.5
40.4
10964.8
0
6
40.4
43651.58
8.684
0.525
For the cases where S > the MPE Limit:
Freq MHz
Power Density (S) at
20 cm mW/cm2
MPE Limit at 20 cm
mW/cm2
Distance where
s<=MPE Limit cm
757.5
27.462
.505
147.5
787.5
8.684
.525
81.3