BMS Truck-Coder II, Installation And Operation Manual, Page: 7 / 49

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WARNING!
RF RADIATION EXPOSURE HAZARD
This warning is provided by Broadcast Microwave Services (BMS) Inc. for safety purpose. The
following information help to reduce the risk of RF exposure hazard.
FCC Limit of RF Exposure
According to Federal Communication Commission (FCC), the Maximum Permissible Exposure (MPE) for
FR radiation has been set to 1.0 mW/cm
2
for the 7GHz Truck-Coder II equipment (OET Bulletin 65).
The 7GHz Truck-Coder II is a non-broadcast transmitter and without an antenna it will not create RF
exposure (power density) exceeding the 1.0 W/cm
2
FCC limit.
However a high-gain antenna such as a parabolic dish will greatly enhance the Field-Coder II output power
density beyond the MPE limit of 1.0 mW/cm
2
.
In this situation a minimum distance from the antenna needs to be calculated in order to keep the MPE
always below the safety limit. The calculation has been done for Field-Coder II based on the formula
mentioned in OET Bulletin 56.
The calculations have been done for different commonly used antenna in Electronic New Gathering (ENG)
systems.
Transmission
Figure 1 shows the plot of the minimum exposure distance for 0dBi, 5dBi, 16dBi, and 30dBi antennas. The
7GHz Truck-Coder II transmits the maximum power of 4 Watts. The minimum exposure distances are
found from the cross points of the exposure graphs (for various antennas) with the line of maximum
permissible exposure (i.e. 1 W/cm
2
). Notice that the numbers in Figure 1 predict the worse case scenario,
which is straight in front of the antenna (exposing to the antenna main-lobe). Obviously the side-lobe
exposures are well below these numbers as the radiation intensity dramatically reduces on the side lobes.
The antenna used for this transmitter must not be co-located or operating in conjunction with any other
antenna or transmitter.
Antenna Specifications
The antenna for Truck-Coder II is customer's furnished equipment. The customer has a choice of using, for
instance, a 0dBi Omni antenna or a 30dBi dish antenna. The plots of Figure 1 provide the exposure distance
for 0dBi and 5dBi Omni antennas as well as 16dBi and 30dBi dish antennas.