Attachment Exhibit C

This document pretains to SES-MOD-20181030-03741 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2018103003741_1562547

        Exhibit B

Radiation Hazard Analysis


                                                     GCI King Salmon 9.1m Radiation Hazard Study



                                                 ANALYSIS OF NON-IONIZING RADIATION
                               FOR THE GCI C-BAND 9.1M EARTH STATION ANTENNA IN KING SALMON, ALASKA
                                                         Completed 10/6/2018

This report analyzes the non-ionizing radiation levels for the GCI 9.1m C-band earth station antenna employed at the King Salmon, Alaska site.
The analysis and calculations performed in this report comply with the methods described in the FCC Office of Engineering and Technology
Bulletin, No. 65 entitled "Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields" - first
published in 1985 and revised in 1997 in Edition 97-01. Bulletin No. 65 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, below. The
General Population/Uncontrolled MPE is a function of the transmit frequency and is for an exposure period of thirty (30) minutes or less. The
MPE limits for persons in an Occupational/Controlled environment are shown in Table 2, below. The Occupational/Controlled MPE is a
function of the transmit frequency and is for an exposure period of six (6) minutes or less. The purpose of the analysis described in this report
is to determine the power flux density levels of the earth station ni the far-field, near-field, transition region, between the subreflector or feed
and the main reflector surface, and at the main reflector surface and to compare these levels to the specified MPE limits.

The results of this analysis are summarized in Table 3 on the last page of this analysis.

                       Table 1. Limits for General Population/Uncontrolled Exposure (MPE)
                     Frequency Range (MHz)                                  Power Density(mW/cm2)
                            30-300                                                    0.2
                           300-1500                                          Frequency (MHz)/1500
                         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)/300
                         1500-100,000                                                 5.0

The following parameters were used to calculate the various power flux densities for this earth station:

           Location:                                   King Salmon, Alaska
           Latitude:                                    58.674133 °N
           Longitude:                                  156.657106 °W
           Operating Frequency:                           6000    MHz
           Wavelength (λ)                                0.04997 meters
           Antenna Diameter (D):                           9.10   meters
           Antenna Area (A):                              65.04   meters²
           Transmit Antenna Gain:                          53.8   dBi
           Transmit Antenna Gain (G):                   239883.3 numeric
           Maximum 5° Off Axis Gain:                       11.5   dBi
           Maximum 5° Off Axis Gain (G5°):                 14.2   numeric
           Antenna Efficiency (ƞ):                        0.733   numeric
           Feed Power (P):                                 400    Watts


1. Antenna/Main Reflector Surface Calculation
The power density in the main reflector region can be estimated by:
                                                                      Antenna Diameter
                                                             9.10   meters
   Power Density at Reflector Surface,        Ssurface = 4P/A
                                              Ssurface =    24.60   W/m²
                                              Ssurface =    2.46    mW/cm²
   Ssurface = maximum power density at antenna surface
         P = power fed to the antenna
         A = physical area of the antenna
2. Near Field Calculations
In the near field region, of the main beam, the power density can reach a maximum before it begins to decrease with distance.
The magnitude of the on axis (main beam) power density varies according to location in the near-field.
The distance to the end of the near field can be determined by the following equation:


                                                                                                                                          Page 1 of 3


                                                         GCI King Salmon 9.1m Radiation Hazard Study

                                                                          Antenna Diameter
                                                              9.10      meters
                       Extent of Near Field,         Rnf = D²/4(λ)
                                                     Rnf = 414.34       meters
       Rnf = extent of near field
        D = maximum dimension of antenna (diameter if circular)
        λ = wavelength
The maximum near-field, on-axis, power density is determined by:
                                                                          Antenna Diameter
                                                               9.10     meters
    On Axis Near Field Power Density,                Snf = 16ƞP/πD²
                                                     Snf =    18.03     W/m²
                                                     Snf =    1.80      mW/cm²
The maximum near-field, 5° off-axis, power density is determined by:
                                                                          Antenna Diameter
                                                                9.10    meters
                Power Density at 5° Off Axis        Snf 5°= (Snf/G)*G5°
                                                    Snf 5°= 0.0001 mW/cm²
       Snf=     maximum near-field power density
     Snf 5° =   maximum near-field power density (5° off axis)
         ƞ=     aperture efficiency
         P=     power fed to antenna
        D=      maximum dimension of antenna (diameter if circular)

3. Far Field Calculations

The power density in the far-field region decreases inversely with the square of the distance.

The distance to the beginning of the far field region can be found by the following equation:

                                                                          Antenna Diameter
                                                               9.10     meters
       Distance to the Far Field Region,             Rff = 0.6D²/λ
                                                     Rff = 994.41       meters

       Rff = distance to beginning of far field
        D = maximum dimension of antenna (diameter if circular)
        λ = wavelength

The maximum main beam power density in the far field can be calculated as follows:
                                                                            Antenna Diameter
                                                                9.10     meters
On-Axis Power Density in the Far Field,               Sff = (P)(G)/4π(Rff)2
                                                      Sff =     7.72     W/m²
                                                      Sff =     0.77     mW/cm²
The maximum far-field, 5° off-axis, power density is determined by:
                                                                          Antenna Diameter
                                                                9.10    meters
                Power Density at 5° Off Axis        Sff 5°= (Sff/G)*G5°
                                                    Sff 5°= 0.0000 mW/cm²
        Sff=    power density (on axis)
     Sff 5°=    power density (5° off axis)
         P=     power fed to antenna
         G=     power gain of antenna in the direction of interest relative to an isotropic radiator
      Rff =     distance to beginning of far field




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Document Created: 2018-10-06 07:16:58
Document Modified: 2018-10-06 07:16:58

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