Attachment v110GX- Exhibit 2

This document pretains to SES-MOD-20130306-00236 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2013030600236_988147

FCC Form 312                              Exhibit 2




               RADIATION HAZARD REPORTS


                                                                         Radiation Hazard Study
                                                                         1.0 m Ku-Band 4 watt




                                       INTRODUCTION

The FCC adopted new guidelines and procedures in 1996 for evaluating environmental effects of
radio frequency (RF) emissions. In order to provide assistance in determining whether proposed
or existing transmitting facilities comply with the new guidelines, the FCC Office of Engineering
and Technology revised OET Bulletin 65. The revised version updates limits for Maximum
Permissible Exposure (MPE) in terms of electric and magnetic field strength and power density
for transmitters operating at frequencies between 300 kHz and 100 GHz. This bulletin was
adopted by the FCC in their General Docket No. 97-303 on August 25,1997. In order to comply
with the requirements of the Report and Order, calculations to determine the power flux densities
in the far field, near field, and reflector regions of the earth station antenna have been made and
are contained in this study.

The FCC guidelines incorporate two separate tiers of exposure limits that are dependent on the
situation in which the exposure takes place and the status of the individuals who are subject to
exposure. The earth station transmitting equipment and antenna are located in an area not
accessible to the general public. Entry is restricted to employees who have been made fully
aware of the potential for human exposure and can exercise control over their exposure.
Therefore occupational / controlled exposure maximum power density limits are used in this
study.

The FCC Office of Engineering and Technology suggests a method for calculating the maximum
values of the power densities emanating from an aperture antenna in OET bulletin 65. This
method is used to determine the power densities associated with the satellite antenna.

The Ku-Band Very Small Aperture Terminal (VSAT ) will be equipped with an amplifier
having a maximum output of 4 watts. The transmitter will feed a 1.0 meter antenna and is
directly attached to the feed horn. The following calculations will be based on a maximum
output power at the antenna flange of 4 watts:


Antenna Surface. The maximum power density directly in front of the antenna may be
expressed as:
                                      4P
                          S surface =
                                       A

                   Where:     S surface = maximum power density at the antenna surface
                                    P = power fed to the antenna
                                    A = physical area of the aperture antenna




                                                1


                                                                       Radiation Hazard Study
                                                                       1.0 m Ku-Band 4 watt




   Using the parameters for this antenna:

              S surface = 4 ( 4 Watts) / π ( 1.0 meters / 2) 2
              S surface = 16 Watts / 0.79 m 2
              S surface = 20.37 Watts / m 2
              S surface = 2.0   mW / cm 2


Near- Field Region. In the near field of the main beam the power density can reach a maximum
before it begins to decrease with distance. The extent of the near field can be described by the
following equation:

                                                        D2
                                                Rnf   =
                                                        4λ

                where: Rnf = extent of near field
                       D = maximum diameter
                       λ = wavelength

   Using the parameters for this antenna:

                λ = 0.02 meters @ 14500 MHz
               Rnf = ( 1.0 meters) 2 / 4( 0.02 meters)
               Rnf =      1.00 / .08 meters
               Rnf =      12.5 meters

The magnitude of the on axis power density varies according to location in the near field.
However, the maximum value of the near field, on axis, power density can be expressed by the
following equation:


                                                       16ηP
                                              S nf =
                                                       πD 2

        where: S nf = maximum near field power density
                η = aperture efficiency
                P = power fed to the antenna
                D = antenna diameter

                                                      2


                                                                          Radiation Hazard Study
                                                                          1.0 m Ku-Band 4 watt




        Using the parameters for this antenna:

               η = .64
               P = 4 Watts
               S nf = 16 (.64) (4 Watts) / π (1.0 meters) 2
               S nf = 40.9 Watts / 3.14 meter 2
               S nf =   13.0 Watts /       meter 2
               S nf =   1.3 mW / cm 2



Far Field Region. For purposes of evaluating RF exposure, the distance to the beginning of the
far field region can be approximated by the following equation:


                                                       0.6 D 2
                                              R ff =
                                                           λ

              where: R ff = distance to the beginning of far field
                     D = diameter of antenna
                     λ = wavelength

              Using the parameters for this antenna:
                     R ff = 0.6 (1.0 meters) 2 / .02 meters
                        R ff = 30 meters

The power density in the far field region of the antenna pattern decreases inversely as the square
of the distance. The power density in the far field region of the radiation pattern can be estimated
by the equation:

                                            S ff = PG / 4πR 2

               where: S ff = power density (on axis)
                      P = power fed to antenna
                      G = power gain of the antenna in the direction of interest
                      R = distance to the point of interest



                                                       3


                                                                       Radiation Hazard Study
                                                                       1.0 m Ku-Band 4 watt




        Using the parameters for this antenna:

                 S ff = 4Watts (41.8 dBi) / 4 (π) ( 30) 2
                 S ff = 60542 / 11310
                 S ff = 5.35 Watts / meter 2
                 S ff = 0.54 mW / cm 2




                                 Main Reflector - Feed horn Region


The RF energy radiated from the feed system is confined to a conical shape whose vertex is
located at the feed and extends outward to the main reflector surface. The power density at any
point in this region is expressed by the equation:


                S feed = P/A
 Where :
           A = Cross section area of the conical region in meter²
           P = Radiated transmitted power in watts

At the feed the power density is:

         S feed = P/A = 4 / π (0.10/ 2 )² = 509 Watts/meter²
         S feed = 51 mW/cm²




                                                    4


                                                                        Radiation Hazard Study
                                                                        1.0 m Ku-Band 4 watt




                                          Conclusion

The results of the above calculations are summarized in the following table and in Figure 1.


             Region                                  Power Density             Remarks


        Antenna Surface                             2.0 mW/cm²                Safe Level

        Main Reflector -Feed horn Region             51 mW/cm²                Hazardous

        Near Field < 12.5       meters              1.3 mW/cm²                 Safe Level

        Far Field     > 30     meters               0.5 mW/cm²                Safe Level



Results of this hazard study indicate that the 5 mW/cm² MPE limit for Occupational/Controlled
Exposure in the 1500 – 100,000 MHz range is not exceeded in areas directly in front of the
antenna, or in the near and far field. The region where this limit may be exceeded will be in the
the region between the reflector and the feed horn. This area is not readily accessible to
personnel and whenever personnel are required to work on the radiating or reflecting parts of the
antenna structure, the transmitter will be turned off. Signs to this effect will be posted at the
transmitter site. The antenna will be located in a restricted area and unauthorized personnel are
prevented access.

Based on this study of predicted radio frequency levels, it is concluded that operation of this
satellite earth station meets OET Bulletin 65 maximum permissible exposure limits and that no
harmful effects will occur to station personnel or anyone within proximity of the station.


Therefore, in accordance with 47 CFR § 1.1307 (b) of the Commission's Rules, preparation and
submission of an Environmental Assessment (EA) is not required.




                                                5


                                                                         Radiation Hazard Study
                                                                         1.0 m Ku-Band 8watt




                                       INTRODUCTION

The FCC adopted new guidelines and procedures in 1996 for evaluating environmental effects of
radio frequency (RF) emissions. In order to provide assistance in determining whether proposed
or existing transmitting facilities comply with the new guidelines, the FCC Office of Engineering
and Technology revised OET Bulletin 65. The revised version updates limits for Maximum
Permissible Exposure (MPE) in terms of electric and magnetic field strength and power density
for transmitters operating at frequencies between 300 kHz and 100 GHz. This bulletin was
adopted by the FCC in their General Docket No. 97-303 on August 25,1997. In order to comply
with the requirements of the Report and Order, calculations to determine the power flux densities
in the far field, near field, and reflector regions of the earth station antenna have been made and
are contained in this study.

The FCC guidelines incorporate two separate tiers of exposure limits that are dependent on the
situation in which the exposure takes place and the status of the individuals who are subject to
exposure. The earth station transmitting equipment and antenna are located in an area not
accessible to the general public. Entry is restricted to employees who have been made fully
aware of the potential for human exposure and can exercise control over their exposure.
Therefore occupational / controlled exposure maximum power density limits are used in this
study.

The FCC Office of Engineering and Technology suggests a method for calculating the maximum
values of the power densities emanating from an aperture antenna in OET bulletin 65. This
method is used to determine the power densities associated with the satellite antenna.

The Ku-Band Very Small Aperture Terminal (VSAT ) will be equipped with an amplifier
having a maximum output of 8 watts. The transmitter will feed a 1.0 meter antenna and is
directly attached to the feed horn. The following calculations will be based on a maximum
output power at the antenna flange of 8 watts:


Antenna Surface. The maximum power density directly in front of the antenna may be
expressed as:
                                      4P
                          S surface =
                                       A

                   Where:     S surface = maximum power density at the antenna surface
                                    P = power fed to the antenna
                                    A = physical area of the aperture antenna




                                                1


                                                                       Radiation Hazard Study
                                                                       1.0 m Ku-Band 8watt




   Using the parameters for this antenna:

              S surface = 4 ( 8 Watts) / π ( 1.0 meters / 2) 2
              S surface = 32 Watts / 0.79 m 2
              S surface = 40.56 Watts / m 2
              S surface = 4.0   mW / cm 2


Near- Field Region. In the near field of the main beam the power density can reach a maximum
before it begins to decrease with distance. The extent of the near field can be described by the
following equation:

                                                        D2
                                                Rnf   =
                                                        4λ

                where: Rnf = extent of near field
                       D = maximum diameter
                       λ = wavelength

   Using the parameters for this antenna:

                λ = 0.02 meters @ 14500 MHz
               Rnf = ( 1.0 meters) 2 / 4( 0.02 meters)
               Rnf =      1.00 / .08 meters
               Rnf =      12.5 meters

The magnitude of the on axis power density varies according to location in the near field.
However, the maximum value of the near field, on axis, power density can be expressed by the
following equation:


                                                       16ηP
                                              S nf =
                                                       πD 2

        where: S nf = maximum near field power density
                η = aperture efficiency
                P = power fed to the antenna
                D = antenna diameter

                                                      2


                                                                          Radiation Hazard Study
                                                                          1.0 m Ku-Band 8watt




        Using the parameters for this antenna:

               η = .64
               P = 8 Watts
               S nf = 16 (.64) (8 Watts) / π (1.0 meters) 2
               S nf = 81.92 Watts / 3.14 meter 2
               S nf =   26.0 Watts /       meter 2
               S nf =   2.6 mW / cm 2



Far Field Region. For purposes of evaluating RF exposure, the distance to the beginning of the
far field region can be approximated by the following equation:


                                                       0.6 D 2
                                              R ff =
                                                           λ

              where: R ff = distance to the beginning of far field
                     D = diameter of antenna
                     λ = wavelength

              Using the parameters for this antenna:
                     R ff = 0.6 (1.0 meters) 2 / .02 meters
                        R ff = 30 meters

The power density in the far field region of the antenna pattern decreases inversely as the square
of the distance. The power density in the far field region of the radiation pattern can be estimated
by the equation:

                                            S ff = PG / 4πR 2

               where: S ff = power density (on axis)
                      P = power fed to antenna
                      G = power gain of the antenna in the direction of interest
                      R = distance to the point of interest



                                                       3


                                                                       Radiation Hazard Study
                                                                       1.0 m Ku-Band 8watt




        Using the parameters for this antenna:

                 S ff = 8Watts (41.8 dBi) / 4 (π) ( 30) 2
                 S ff = 121084 / 11310
                 S ff = 10.7 Watts / meter 2
                 S ff = 1.1 mW / cm 2




                                 Main Reflector - Feed horn Region


The RF energy radiated from the feed system is confined to a conical shape whose vertex is
located at the feed and extends outward to the main reflector surface. The power density at any
point in this region is expressed by the equation:


                S feed = P/A
 Where :
           A = Cross section area of the conical region in meter²
           P = Radiated transmitted power in watts

At the feed the power density is:

         S feed = P/A = 8 / π (0.10/ 2 )² = 1018 Watts/meter²
         S feed = 102 mW/cm²




                                                    4


                                                                        Radiation Hazard Study
                                                                        1.0 m Ku-Band 8watt




                                          Conclusion

The results of the above calculations are summarized in the following table and in Figure 1.


             Region                                  Power Density             Remarks


        Antenna Surface                             4.0 mW/cm²                Safe Level

        Main Reflector -Feed horn Region            102 mW/cm²                 Hazardous

        Near Field < 12.5       meters              2.6 mW/cm²                 Safe Level

        Far Field     > 30     meters               1.1 mW/cm²                Safe Level



Results of this hazard study indicate that the 5 mW/cm² MPE limit for Occupational/Controlled
Exposure in the 1500 – 100,000 MHz range is not exceeded in areas directly in front of the
antenna, or in the near and far field. The region where this limit may be exceeded will be in the
the region between the reflector and the feed horn. This area is not readily accessible to
personnel and whenever personnel are required to work on the radiating or reflecting parts of the
antenna structure, the transmitter will be turned off. Signs to this effect will be posted at the
transmitter site. The antenna will be located in a restricted area and unauthorized personnel are
prevented access.

Based on this study of predicted radio frequency levels, it is concluded that operation of this
satellite earth station meets OET Bulletin 65 maximum permissible exposure limits and that no
harmful effects will occur to station personnel or anyone within proximity of the station.


Therefore, in accordance with 47 CFR § 1.1307 (b) of the Commission's Rules, preparation and
submission of an Environmental Assessment (EA) is not required.




                                                5



Document Created: 2013-01-29 12:22:23
Document Modified: 2013-01-29 12:22:23

© 2024 FCC.report
This site is not affiliated with or endorsed by the FCC