Attachment Rad Haz 4.5 m

This document pretains to SES-DBM-INTR2019-00975 for Database Entry MOD on a Satellite Earth Station filing.


                                                                                  Exhibit
Radiation Hazard Report                                                           Page 1 of 5


      Analysis of Non-Ionizing Radiation for a 4.5-Meter Earth
                          Station System
This report analyzes the non-ionizing radiation levels for a 4.5-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                   4.5            m
     Antenna Surface Area          Asurface         π D2 / 4               15.90            m2
     Subreflector Diameter          Dsr              Input                  61.6            cm
     Area of Subreflector           Asr             π Dsr 2/4             2979.27           cm2
     Frequency                       F               Input                  6175            MHz
     Wavelength                      λ              300 / F              0.048583           m
     Transmit Power                  P               Input                 30.00            W
     Antenna Gain (dBi)             Ges              Input                  46.3            dBi
     Antenna Gain (factor)           G              10Ges/10              42658.0           n/a
     Pi                              π             Constant              3.1415927          n/a
     Antenna Efficiency              η             Gλ2/(π2D2)               0.50            n/a


                                                                                  Exhibit
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)
                                                                = 250.1 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)
                                                                = 1.628 W/m2
                                                                = 0.163 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)
                                                                = 104.2 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)
                                                                = 3.801 W/m2
                                                                = 0.380 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)
                                                               = 0.380 mW/cm2


                                                                              Exhibit
Radiation Hazard Report                                                       Page 3 of 5



4.      Region between the Main Reflector and the Subreflector

Transmissions from the feed assembly are directed     toward the subreflector surface, and are
reflected back toward the main reflector. The most    common feed assemblies are waveguide
flanges, horns or subreflectors. The energy between   the subreflector and the reflector surfaces
can be calculated by determining the power density    at the subreflector surface. This can be
determined from the following equation:

     Power Density at the Subreflector                    Ssr = 4000 P / Asr                (6)
                                                              = 40.278 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 subreflector. The area is now the area of the main reflector aperture and can be determined
from the following equation:

     Power Density at the Main Reflector Surface      Ssurface = 4 P / Asurface             (7)
                                                               = 7.545 W/m2
                                                               = 0.755 mW/cm2


6.      Region between the Main 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)
                                                             = 1.886 W/m2
                                                             = 0.189 mW/cm2


                                                                                      Exhibit
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 = 250.1 m)                    Sff        0.163            Satisfies FCC MPE
2. Near Field (Rnf = 104.2 m)                   Snf        0.380            Satisfies FCC MPE
3. Transition Region (Rnf < Rt < Rff)           St         0.380            Satisfies FCC MPE
4. Between Main Reflector and                   Ssr       40.278             Potential Hazard
    Subreflector
5. Main Reflector                               Ssurface   0.755            Satisfies FCC MPE
6. Between Main Reflector and Ground            Sg         0.189            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 = 250.1 m)                   Sff         0.163            Satisfies FCC MPE
2. Near Field (Rnf = 104.2 m)                  Snf         0.380            Satisfies FCC MPE
3. Transition Region (Rnf < Rt < Rff)          St          0.380            Satisfies FCC MPE
4. Between Main Reflector and                  Ssr       40.278              Potential Hazard
    Subreflector
5. Main Reflector                              Ssurface    0.755            Satisfies FCC MPE
6. Between Main Reflector and Ground           Sg          0.189            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.



8.     Conclusions

Based on the above analysis it is concluded that harmful levels of radiation will not exist in regions
normally occupied by the public or the earth station's operating personnel. The transmitter will be
turned off during antenna maintenance so that the FCC MPE of 5.0 mW/cm2 will be complied with
for those regions with close proximity to the reflector that exceed acceptable levels.

The earth station’s operational staff will not have access to the areas that exceed the MPE levels
while the earth station is in operation.

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


                                                                                       Exhibit
Radiation Hazard Report                                                                Page 5 of 5

        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 worker.


I HEREBY CERTIFY THAT I AM THE TECHNICALLY QUALIFIED PERSON RESPONSIBLE FOR THE
PREPARATION OF THE RADIATION HAZARD REPORT, AND THAT IT IS COMPLETE AND CORRECT
TO THE BEST OF MY KNOWLEDGE AND BELIEF.




BY: _

Gary K. Edwards
Senior Manager
COMSEARCH
19700 Janelia Farm Boulevard
Ashburn, VA 20147


DATED: December 16, 2015



Document Created: 2016-02-23 15:50:19
Document Modified: 2016-02-23 15:50:19

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