Attachment Rdhz.doc

This document pretains to SES-MOD-20100615-00701 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2010061500701_822589

     EXHIBIT B

Radiation Hazard Study


                                                                                     SES Americom


                                           SES Americom, Inc.
                                           Four Research Way, Princeton, NJ 08540-6684


RADIATION HAZARD STUDY

When applying for a license to construct and operate, modify, or renew an earth station,
it is understood that licensees must certify whether grant of the application will have
significant environmental impact as defined in the Federal Communications
Commission’s (FCC) rules, 47 C.F.R., Section 1.1307.

In this report SES Americom, Inc. analyzes the maximum radiofrequency (RF) levels
emitted from the satellite communications antenna described below. The reference
document for this study is OET Bulletin No. 65, Edition 97-01, Evaluating Compliance
with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields,
August 1997.


I.    Antenna Near-Field Power Density Calculation

      The extent of the near-field is defined by the following equation:

                           Rnear = (Dant)2 / (4 )

      where:        Rnear = extent of the near-field (in meters)
                    Dant = diameter of the antenna main reflector (in meters)
                     = wavelength of the RF transmit frequency (in meters)

      The maximum on-axis power density within near-field is defined by the following
      equation:

                           Snear = {(16 Pfeed) / [ (Dant)2]} / 10

      where:        Snear = maximum on-axis power density within the near-field (in
                            milliwatts per square centimeter)
                      = antenna aperature efficiency
                    Pfeed = maximum power into antenna feed flange (in watts)
                    Dant = diameter of the antenna main reflector (in meters)

II.   Antenna Far-Field Power Density Calculation

      The distance to the beginning of the far-field region is defined by the following
      equation:

                            Rfar = [0.6(Dant)2] /
      where:        Rfar = distance to beginning of far-field (in meters)
                    Dant = diameter of the antenna main reflector (in meters)
                      = wavelength of the RF transmit frequency in (meters)


       The maximum on-axis power density within the far-field is defined by the
       following equation:
                           Sfar = [(Pfeed Gant) / 4 (Rfar)2] / 10

       where:       Sfar = maximum on-axis power density in the far-field (in milliwatts
                           per square centimeter)
                    Pfeed = maximum power into antenna feed flange (in watts)
                    Gant = antenna main beam gain at RF transmit frequency (in watts)
                    Rfar = distance to beginning of far-field (in meters)

III.   Antenna Transition Region Power Density Calculation

       By definition, the maximum on-axis power densitiy in the transition region will
       never be greater than the maximum on-axis power densities in the near-field:

                           Str   Snear

       where:       Str = maximum on-axis power density in the transition region (in
                          milliwatts per square centimeter)
                    Snear = maximum on-axis power density in the near-field (in
                            milliwatts per square centimeter)

IV.    Antenna Feed-Flange (or Subreflector) Power Density Calculation

       The maximum power density at the antenna feed-flange (or subreflector surface)
       is defined by the following equation:

                           Sfeed(sub) = 1000 {[2(Pfeed)] / {[ (Dfeed(sub))2 ] / 4}}

       where:       Sfeed(sub) = maximum power density at the antenna feed-flange or
                                subreflector surface (in milliwatts per square centimeter)
                    Pfeed = maximum power into antenna feed flange (in watts)
                    Dfeed(sub) = diameter of the antenna feed-flange or subreflector (in
                                 centimeters)

V.     Antenna Main Reflector Power Density Calculation

       The maximum power density in the main reflector region of the antenna is
       defined by the following equation:

                           Sant = {[2(Pfeed)] / {[ (Dant)2 ] / 4}} / 10

       where:       Sant = maximum power density in the antenna main reflector region
                           (in milliwatts per square centimeter)
                    Pfeed = maximum power into antenna feed flange (in watts)
                    Dant = diameter of the antenna main reflector (in meters)



VI.    Power Density Calculation between the Antenna Main Reflector and the Ground


        The maximum power density between the antenna main reflector and the ground
        is defined by the following equation:

                               Sground = {Pfeed / {[ (Dant)2 ] / 4}} / 10

        where:          Sground = maximum power density between the antenna main
                                        reflector and the ground (in milliwatts per square
                                        centimeter)
                        Pfeed = maximum power into antenna feed flange (in watts)
                        Dant = diameter of the antenna main reflector (in meters)

VII.    Summary of Calculated Radiation Levels

SES Americom , Inc. understands the licensee must ensure people are not exposed to
harmful levels of radiation.

Maximum permissible exposure (MPE) limits for general population/uncontrolled
exposure were not considered in this analysis for several reasons. The main-beam
orientation and height above ground of this highly directional antenna significantly limit
exposure to the general population. Furthermore, access to SES Americom stations is
limited to authorized personnel who have been appropriately briefed and advised.

MPE limits for occupational/controlled exposure, however, were considered in this
analysis. It is standard practice for our technical staff to cease transmissions whenever
maintenance is performed in close proximity to antenna reflector regions with potentially
hazardous power density levels. Based on the results (see next page entitled
“Radiation Hazard Calculations”) and our standard practices within our controlled
antenna environment, the earth station operators / technicians should not be exposed to
radiation levels exceeding 5 mW/cm2 power density over a six minute averaging time.
VIII.   Certification

I hereby certify that I am the technically qualified person responsible for preparation of
the engineering information contained in this radiation hazard assessment, that I have
reviewed the engineering information submitted, and that it is complete and accurate to
the best of my knowledge.




Tom Koukourdelis
Senior Engineer, Ground Systems
SES Engineering, Inc.


Antenna main reflector diameter                               9.3   m
Feed flange (or subreflector) diameter                      122.0   cm
RF transmit frequency                                       6.100   GHz
Maximum power into antenna feed-flange                    1543.00   W
Main-beam gain of antenna (at RF transmit frequency)         53.8   dBi
                                                         239883.3   W
Antenna aperature efficiency                                 0.55
Antenna main reflector surface area                         67.93   m^2
Feed flange (or subreflector) surface area               11689.87   cm^2
Wavelength of the RF transmit frequency                     0.049   m
Distance to beginning of far-field region                 1055.88   m
Distance to extent of near-field region                    439.95   m



Max. on-axis power density [far-field]                     2.64     mW/cm^2   SATISFIES MPE L
Max. on-axis power density [near-field]                    5.00     mW/cm^2   SATISFIES MPE L
Max. on-axis power density [transition region]             5.00     mW/cm^2   SATISFIES MPE L
Max. power density [feed-flange or subreflector]         263.99     mW/cm^2    POTENTIAL HAZ
Max. power density [main reflector region]                 4.54     mW/cm^2   SATISFIES MPE L
Max. power density [between main reflector and ground]     2.27     mW/cm^2   SATISFIES MPE L



Document Created: 2010-06-16 10:13:38
Document Modified: 2010-06-16 10:13:38

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