Attachment E050380

This document pretains to SES-LIC-20051210-01716 for License on a Satellite Earth Station filing.

IBFS_SESLIC2005121001716_472420

                                                                                         Exhibit B
Radiation Hazard Report                                                                  Page 1 of 5


      Analysis of Non-Ionizing Radiation for a 2.4-Meter Earth
                          Station System
This report analyzes the non-ionizing radiation levels for a 2.4-meter earth station system. The analysis and
calculations performed in this report comply with the methods described in the FCC Office of Engineering
and Technology Bulletin, No. 65 first published in 1985 and revised in 1997 in Edition 97-01. The radiation
safety limits used in the analysis are in conformance with the FCC R&O 96-326. Bulletin No. 65 and the
FCC R&O specifies that there are two separate tiers of exposure limits that are dependant on the situation in
which the exposure takes place and/or the status of the individuals who are subject to the exposure. The
Maximum Permissible Exposure (MPE) limits for persons in a General Population/Uncontrolled environment
are shown in Table 1. The General Population/Uncontrolled MPE is a function of transmit frequency and is
for an exposure period of thirty minutes or less. The MPE limits for persons in an Occupational/Controlled
environment are shown in Table 2. The Occupational MPE is a function of transmit frequency and is for an
exposure period of six minutes or less. The purpose of the analysis described in this report is to determine
the power flux density levels of the earth station in the far-field, near-field, transition region, between the
subreflector or feed and main reflector surface, at the main reflector surface, and between the antenna edge
and the ground and to compare these levels to the specified MPEs.

                Table 1. Limits for General Population/Uncontrolled Exposure (MPE)
                   Frequency Range (MHz)            Power Density (mW/cm2)
                           30-300                                0.2
                          300-1500                    Frequency (MHz)*(0.8/1200)
                        1500-100,000                             1.0

                     Table 2. Limits for Occupational/Controlled Exposure (MPE)
                   Frequency Range (MHz)            Power Density (mW/cm2)
                           30-300                                1.0
                          300-1500                    Frequency (MHz)*(4.0/1200)
                        1500-100,000                             5.0


          Table 3. Formulas and Parameters Used for Determining Power Flux Densities
     Parameter                       Symbol            Formula                   Value            Units
     Antenna Diameter                   D                Input                     2.4            m
     Antenna Surface Area             Asurface          π D2 / 4                  4.52            m2
     Feed Flange Diameter              Dfa               Input                     8.1            cm
     Area of Feed Flange               Afa              π Dfa 2/4                 51.53           cm2
     Frequency                          F                Input                    6175            MHz
     Wavelength                         λ               300 / F                0.048583           m
     Transmit Power                     P                Input                    20.00           W
     Antenna Gain (dBi)                Ges               Input                     41.7           dBi
     Antenna Gain (factor)              G               10Ges/10                14791.1           n/a
     Pi                                 π              Constant                3.1415927          n/a
     Antenna Efficiency                 η              Gλ2/(π2D2)                 0.61            n/a


                                                                                  Exhibit B
Radiation Hazard Report                                                           Page 2 of 5



1.      Far Field Distance Calculation

The distance to the beginning of the far field can be determined from the following equation:

     Distance to the Far Field Region                       Rff = 0.60 D2 / λ                   (1)
                                                                = 71.1 m

The maximum main beam power density in the far field can be determined from the following
equation:

     On-Axis Power Density in the Far Field                 Sff = G P / (4 π Rff 2)             (2)
                                                                = 4.652 W/m2
                                                                = 0.465 mW/cm2

2.      Near Field Calculation

Power flux density is considered to be at a maximum value throughout the entire length of the
defined Near Field region. The region is contained within a cylindrical volume having the same
diameter as the antenna. Past the boundary of the Near Field region, the power density from the
antenna decreases linearly with respect to increasing distance.

The distance to the end of the Near Field can be determined from the following equation:

     Extent of the Near Field                               Rnf = D2 / (4 λ)                    (3)
                                                                = 29.6 m

The maximum power density in the Near Field can be determined from the following equation:

     Near Field Power Density                               Snf = 16.0 η P / (π D2)             (4)
                                                                = 10.860 W/m2
                                                                = 1.086 mW/cm2

3.      Transition Region Calculation

The Transition region is located between the Near and Far Field regions. The power density
begins to decrease linearly with increasing distance in the Transition region. While the power
density decreases inversely with distance in the Transition region, the power density decreases
inversely with the square of the distance in the Far Field region. The maximum power density in
the Transition region will not exceed that calculated for the Near Field region. The power density
calculated in Section 1 is the highest power density the antenna can produce in any of the regions
away from the antenna. The power density at a distance Rt can be determined from the following
equation:

     Transition Region Power Density                        St = Snf Rnf / Rt                   (5)
                                                               = 1.086 mW/cm2


                                                                              Exhibit B
Radiation Hazard Report                                                       Page 3 of 5



4.      Region between the Feed Assembly and the Antenna Reflector

Transmissions from the feed assembly are directed toward the antenna reflector surface, and are
confined within a conical shape defined by the type of feed assembly. The most common feed
assemblies are waveguide flanges, horns or subreflectors. The energy between the feed assembly
and reflector surface can be calculated by determining the power density at the feed assembly
surface. This can be determined from the following equation:

     Power Density at the Feed Flange                     Sfa = 4000 P / Afa                (6)
                                                              = 1552.494 mW/cm2


5.      Main Reflector Region

The power density in the main reflector is determined in the same manner as the power density at
the feed assembly. The area is now the area of the reflector aperture and can be determined from
the following equation:

     Power Density at the Reflector Surface           Ssurface = 4 P / Asurface             (7)
                                                               = 17.684 W/m2
                                                               = 1.768 mW/cm2


6.      Region between the Reflector and the Ground

Assuming uniform illumination of the reflector surface, the power density between the antenna and
the ground can be determined from the following equation:

     Power Density between Reflector and Ground           Sg = P / Asurface                 (8)
                                                             = 4.421 W/m2
                                                             = 0.442 mW/cm2


                                                                             Exhibit B
Radiation Hazard Report                                                      Page 4 of 5



7.     Summary of Calculations

          Table 4. Summary of Expected Radiation levels for Uncontrolled Environment

                                            Calculated Maximum
                                        Radiation Power Density Level
Region                                             (mW/cm2)                Hazard Assessment
1. Far Field (Rff = 71.1 m)                    Sff       0.465              Satisfies FCC MPE
2. Near Field (Rnf = 29.6 m)                   Snf       1.086               Potential Hazard
3. Transition Region (Rnf < Rt < Rff)          St        1.086               Potential Hazard
4. Between Feed Assembly and                   Sfa    1552.494               Potential Hazard
    Antenna Reflector
5. Main Reflector                               Ssurface   1.768             Potential Hazard
6. Between Reflector and Ground                 Sg         0.442            Satisfies FCC MPE



           Table 5. Summary of Expected Radiation levels for Controlled Environment

                                            Calculated Maximum
                                           Radiation Power Density
Region                                         Level (mW/cm2)             Hazard Assessment
1. Far Field (Rff = 71.1 m)                    Sff       0.465             Satisfies FCC MPE
2. Near Field (Rnf = 29.6 m)                   Snf       1.086             Satisfies FCC MPE
3. Transition Region (Rnf < Rt < Rff)          St        1.086             Satisfies FCC MPE
4. Between Feed Assembly and                   Sfa    1552.494              Potential Hazard
    Antenna Reflector
5. Main Reflector                               Ssurface   1.768           Satisfies FCC MPE
6. Between Reflector and Ground                 Sg         0.442           Satisfies FCC MPE




It is the applicant's responsibility to ensure that the public and operational personnel are not
exposed to harmful levels of radiation.


                                                                                 Exhibit B
Radiation Hazard Report                                                          Page 5 of 5




8.     Conclusions

Based upon the above analysis, it is concluded that harmful levels of radiation may exist in those
regions noted for the Uncontrolled (Table 4) environment.

The earth station will be installed 12 feet above the main deck of an oil platform, and public access
to the earth station is restricted.

The applicant will ensure that the main beam of the antenna will be pointed at least one diameter
away from any buildings, or other obstacles in those areas that exceed the MPE levels. Since one
diameter removed from the center of the main beam the levels are down at least 20 dB, or by a
factor of 100, public safety will be ensured.

The earth station will marked with the standard radiation hazard warnings, as well as the area in
the vicinity of the earth station, to inform those in the general population, who may be working, or
otherwise present on the roof, and in or near, the main beam of the antenna.

Finally, occupational exposure will be limited, and the transmitter will be turned off during periods
of maintenance, so that the MPE standard of 5.0 mw/cm**2 will be complied with for those regions
in close proximity to the main reflector, and subreflector, which could be occupied by operating
personnel.



Document Created: 2005-12-15 16:03:35
Document Modified: 2005-12-15 16:03:35

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