Attachment Exhibit B

This document pretains to SES-MOD-20141231-00925 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2014123100925_1072171

Radiation Hazard Report                                                                      Exhibit B
                                                                                           Page 1 of 5


       Analysis of Non-Ionizing Radiation for a 4.0-Meter
          Inflatable Earth Station Antenna System
This report analyzes the non-ionizing radiation levels for a 4.0-meter inflatable 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 dependent 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 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 feed and reflector surface, at the reflector surface, between the antenna edge
and the ground, and off-axis in the near-field, 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)           Averaging Time (minutes)
             30 - 300                        0.2                               30
            300 - 1500              Frequency [MHz] / 1500                     30
           1500 - 100000                     1.0                               30

                   Table 2. Limits for Occupational/Controlled Exposure (MPE)
      Frequency Range (MHz)        Power Density (mW/cm2)           Averaging Time (minutes)
             30 - 300                         1.0                               6
            300 - 1500               Frequency [MHz] / 300                      6
           1500 - 100000                      5.0                               6

          Table 3. Formulas and Parameters Used for Determining Power Flux Densities
        Parameter                   Symbol         Formula             Value        Units
        Antenna Diameter               D             Input               4.0       m
        Antenna Surface Area        Asurface       π ∙ D2 /4           12.566      m2
        Feed Flange Diameter          Dfa            Input               6.5       cm
        Area of Feed Flange           Afa         π ∙ Dfa 2 /4         33.183      cm2
        Frequency                      F             Input             14250       MHz
        Wavelength                     λ              c/F             0.02104      m
        Transmit Power                 P             Input              100        Watts
        Antenna Gain (dBi)            Ges            Input              53.6       dBi
        Antenna Gain (factor)          G           10Ges /10        2.291 ∙ 105    -
        Antenna Efficiency             η       G ∙ λ2 /(π2 ∙ D2 )     0.64208      -
        Pi                             π           Constant         3.14159265     -
        Speed of Light                 c           Constant         2.9979 ∙ 108   m/s


GATR Technologies, Inc.


Radiation Hazard Report                                                                              Exhibit B
                                                                                                   Page 2 of 5


1.      Far Field Calculation
The distance to the beginning of the Far Field can be determined from the following equation:

                                                                0.60∙D2
     Distance to the Far Field Region                  R ff =      λ
                                                                               = 456.316 m                  (1)

The maximum main beam power density in the Far Field can be determined from the following
equation:
                                                                 G∙P                              mW
     On-Axis Far Field Power Density                   Sff = 4∙π∙R         2   = 8.755 mW2 = 0.876 cm2      (2)
                                                                      ff




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:

                                                                D2
     Extent of the Near Field                          R nf =         = 190.132 m                           (3)
                                                                4∙λ

The maximum main beam power density in the Near Field can be determined from the following
equation:
                                                                16.0∙η∙P                              mW
     On-Axis Near Field Power Density                  Snf =                   = 20.438 mW2 = 2.044         (4)
                                                                 π∙D2                                 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:
                                                              Snf ∙Rnf             mW
     Transition Region Power Density                   St =     Rt
                                                                           = 2.044 cm 2                     (5)




GATR Technologies, Inc.


Radiation Hazard Report                                                                             Exhibit B
                                                                                                  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 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 form the following equation:
                                                               4000∙P                mW
     Power Density at the Feed Flange                  Sfa =    Afa
                                                                          = 12054    cm2
                                                                                                          (6)



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:
                                                                          4∙P               mW
     Power Density at the Reflector Surface            Ssurface = A               = 3.183   cm2
                                                                                                          (7)
                                                                        surface




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:
                                                                  P                  mW
     Power Density between Reflector and Ground        Sg = A             = 0.796    cm2
                                                                                                          (8)
                                                                surface




7.      Near Field Off-Axis Calculation
For off-axis calculations in the near-field and in the transition region, it can be assumed that, at
distances of at least one diameter removed from the center of the main beam, the power density
will be a least 20 dB less than the value calculated for the equivalent distance in the main beam.
Therefore, for off-axis regions at least 4 meters away from the center of the main beam, the power
density can be determined from the following equation:
                                                                                       mW
     Off-Axis Near Field Power Density                 Snf−offa = Snf − 20dB = 0.02044 cm 2               (9)




GATR Technologies, Inc.


Radiation Hazard Report                                                                 Exhibit B
                                                                                      Page 4 of 5

8.     Summary of Calculations
            Table 4. Summary of Expected Radiation Levels for Uncontrolled Environment
                                          Calculated Maximum Radiation
Region                                         Power Density Level          Hazard Assessment
                                                     (mW/cm2)
1. Far Field (R t ≥ R ff = 456.316 m)            Sff          0.876          Satisfies FCC MPE
2. Near Field (R t ≤ R nf = 190.132 m)           Snf          2.044           Potential Hazard
3. Transition Region (R nf < R t < R ff )        St           2.044           Potential Hazard
4. Between Feed Assembly and
                                                 Sfa      12054.340           Potential Hazard
   Antenna Reflector
5. Main Reflector                                Ssurface     3.183           Potential Hazard
6. Between Reflector and Ground                  Sg           0.796          Satisfies FCC MPE
7. Off-Axis Near Field                           Snf−offa     0.020          Satisfies FCC MPE


             Table 5. Summary of Expected Radiation Levels for Controlled Environment
                                          Calculated Maximum Radiation
Region                                         Power Density Level          Hazard Assessment
                                                     (mW/cm2)
1. Far Field (R t ≥ R ff = 456.316 m)            Sff          0.876           Satisfies FCC MPE
2. Near Field (R t ≤ R nf = 190.132 m)           Snf          2.044           Satisfies FCC MPE
3. Transition Region (R nf < R t < R ff )        St           2.044           Satisfies FCC MPE
4. Between Feed Assembly and
                                                 Sfa      12054.340           Potential Hazard
   Antenna Reflector
5. Main Reflector                                Ssurface     3.183           Satisfies FCC MPE
6. Between Reflector and Ground                  S g          0.796           Satisfies FCC MPE
7. Off-Axis Near Field                           Snf−offa     0.020           Satisfies FCC MPE




9.     Conclusions
Based upon the above analysis, it is concluded that FCC RF Guidelines have been exceeded in
the specified region(s) of Table 4 and Table 5. The applicant proposes to comply with the MPE
limits by one or more of the following methods.

The applicant will ensure that the main beam of the antenna will be pointed at least one diameter
(4 meters) away from any buildings or other obstacles in those areas that exceed the MPE levels.
The area around the antenna equal to one diameter removed from the main beam will be secured
off, and public access will be denied. This distance satisfies the FCC MPE for both Controlled and
Uncontrolled Environments. In addition, radiation hazard decals attached to the antenna radome
will further indicate to the general public the potential hazard associated closer to the antenna.

All operating personnel will be trained and made aware of the human exposure levels at and
around the earth station. Specifically, concerning Region 4: due to the Antenna Reflector being


GATR Technologies, Inc.


Radiation Hazard Report                                                                        Exhibit B
                                                                                             Page 5 of 5
confined to a radome on which the Feed Assembly rests, the region between the Feed Assembly
and Antenna Reflector is only physically accessible between the Feed Assembly and radome
surface, a gap of less than 3 inches. At a worst-case antenna elevation angle of 5°, the Feed
Assembly will be approximately 7 feet above the ground. This confines the potential hazard to a
very small area and only reachable in a limited number of circumstances. Furthermore, the earth
station’s operating personnel will not require access to this area while the earth station is in
operation, and the transmitter will be turned off during any antenna maintenance.

The applicant agrees to abide by the conditions specified in Condition 5208 provided below:

       Condition 5208 – The licensee shall take all necessary measures to ensure that the
       antenna does not create potential exposure of humans to radiofrequency radiation in
       excess of the FCC exposure limits defined in 47 CFR §§1.1307(b) and 1.1310
       wherever such exposures might occur. Measures must be taken to ensure
       compliance with limits for both occupational/controlled exposure and for general
       population/uncontrolled exposure, as defined in these rule sections. Compliance can
       be accomplished in most cases by appropriate restrictions such as fencing.
       Requirements for restrictions can be determined by predictions based on
       calculations, modeling or by field measurements. The FCC’s OET Bulletin 65
       (available on-line at www.fcc.gov/oet/rfsafety) provides information on predicting
       exposure levels and on methods for ensuring compliance, including the use of
       warning and alerting signs and protective equipment for workers.




GATR Technologies, Inc.



Document Created: 2014-12-09 20:32:52
Document Modified: 2014-12-09 20:32:52

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