Attachment Radhaz report

This document pretains to SES-MOD-20190225-00226 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2019022500226_1589658

                                                                                      Exhibit
Radiation Hazard Report                                                               Page 1 of 5


      Analysis of Non-Ionizing Radiation for a 3.7-Meter Earth
                          Station System
This report analyzes the non-ionizing radiation levels for a 3.7-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                   3.7              m
      Antenna Surface Area           Asurface         π D2 / 4                10.75             m2
      Subreflector Diameter           Dsr              Input                  23.7              cm
      Area of Subreflector            Asr             π Dsr 2/4              441.90             cm2
      Frequency                        F               Input                 14250              MHz
      Wavelength                       λ              300 / F              0.021053             m
      Transmit Power                   P               Input                 400.00             W
      Antenna Gain (dBi)              Ges              Input                  52.7              dBi
      Antenna Gain (factor)            G              10Ges/10             186208.7             n/a
      Pi                               π             Constant              3.1415927            n/a
      Antenna Efficiency               η             Gλ2/(π2D2)               0.61              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)
                                                                = 390.2 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)
                                                                = 38.936 W/m2
                                                                = 3.894 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)
                                                                = 162.6 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)
                                                                = 90.894 W/m2
                                                                = 9.089 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)
                                                               = 9.089 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)
                                                               = 3620.768 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)
                                                                 = 148.808 W/m2
                                                                 = 14.881 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)
                                                              = 37.202 W/m2
                                                              = 3.720 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                Hazard
 Region                                        Level (mW/cm2)                  Assessment
 1. Far Field (Rff = 390.2 m)                   Sff         3.894           Potential Hazard
 2. Near Field (Rnf = 162.6 m)                  Snf         9.089           Potential Hazard
 3. Transition Region (Rnf < Rt < Rff)          St          9.089           Potential Hazard
 4. Between Main Reflector and                  Ssr      3620.768           Potential Hazard
     Subreflector
 5. Main Reflector                              Ssurface   14.881           Potential Hazard
 6. Between Main Reflector and Ground           Sg          3.720           Potential Hazard

             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 = 390.2 m)                   Sff         3.894           Satisfies FCC MPE
 2. Near Field (Rnf = 162.6 m)                  Snf         9.089            Potential Hazard
 3. Transition Region (Rnf < Rt < Rff)          St          9.089            Potential Hazard
 4. Between Main Reflector and                  Ssr      3620.768            Potential Hazard
     Subreflector
 5. Main Reflector                              Ssurface   14.881            Potential Hazard
 6. Between Main Reflector and Ground           Sg          3.720           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 the FCC MPE guidelines have been exceeded (or
met) in the regions of Table 4 and 5. The applicant proposes to comply with the MPE limits by one
or more of the following methods.

Radiation hazard signs will be posted while this earth station is in operation.

Due to the remote and secure location of the proposed earth station antenna at the Brewster
Teleport, the area of operation around the antenna will be limited to those that have knowledge of
the potential for radiation exposure. The applicant will ensure that no buildings or other obstacles
will be in the areas that exceed the MPE levels.


                                                                                       Exhibit
Radiation Hazard Report                                                                Page 5 of 5

Means of Compliance Controlled Areas

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 transmitters will be turned off during 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 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 12, 2018



Document Created: 2018-12-12 16:13:33
Document Modified: 2018-12-12 16:13:33

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