User's Manual

Help Hot Line (U.S. only): 1-800-530-9960 B-3
D-620616-0-20 Rev A CONFIDENTIAL
• Above 1.5 GHz the limit is 1mW/cm2
The basic equation for determining power density is:
S = PG / 4πR
2
Where S is power density in mW/cm2
PG, the transmitted power from the antenna identified as EIRP (Equivalent Isotropi-
cally Radiated Power), is the product of power output of device and antenna gain, in
mW.
R is the distance of interest from the antenna.
Typical Installation Example:
Assuming an antenna is placed on a 10 foot ceiling, for a person 6 feet tall, the dis-
tance from antenna to body is 4 feet (112 cm.).
For a PCS 1900 remote unit, the maximum power output, according to the power
table in Section 6.3 Maximum Output Power per Carrier on page 6-4, is 16.5 dB.
Assuming a 7 dBi antenna is used, PG in the equation is equal to 23.5 dB (224 mW)
EIRP.
Using S = PG/4
πR
2
S = 224/(4x3.14) x (122)
2
= 0.001 mW/cm
2
Also, assuming a minimum distance of 20 cm according to FCC regulations”
S = 224/(4 x 3.14) x (20)
2
= 0.04 mW/cm
2