User's Manual

MHX-920 Operating Manual:Glossary 9
A. Antenna / Separations
Antenna
Impedance
(ohms)
Antenna Gain (dBi)
Minimum Separation
Distance (cm)
Minimum Gain
50
0
39
Maximum Gain
50 18 305
RF EXPOSURE DISTANCE LIMITS
S
EIRP
S
GP
r
⋅⋅
=
⋅⋅
⋅
=
ππ 44
Sample calculation:
S = 406.1/1500 mW/cm
2
EIRP = 42 dBm = 10
42/10
mW = 15849 mW (Worst Case for Quarter Wave antenna)
(Minimum Safe Distance, r) =
cm
S
EIRP
68
)1500/1.406(4
15849
4
≈
⋅⋅
=
⋅⋅
ππ
WARNING:
Changes or modifications not expressly approved by Microhard Systems Inc. could void the user’s
authority to operate the equipment. Please Contact Microhard Systems Inc. if you need more information.
WARNING:
To satisfy FCC RF exposure requirements for mobile transmitting devices, a separation distance is based
on the above them ranging from 39 cm to 305 cm between the antenna of this device and persons during
device operation. To ensure compliance, operations at closer than this distance is not recommended. The
antenna used for this transmitter must not be co-located in conjunction with any other antenna or
transmitter.