Attachment Rad. Hazard Study

This document pretains to SES-LIC-20110615-00710 for License on a Satellite Earth Station filing.

IBFS_SESLIC2011061500710_893478

Exhibit A Radiation Hazard Study

EXHIBIT A Page 1 of 5 Analysis of Non—Ionizing Radiation for a 5.6 Meter Earth Station System This report analyzes the non—ionizing radiation levels for a 5.6 meter earth station system. The analysis and calculations performed in this report are in compliance 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 MPESs. Table 1. Limits for General Population/Uncontrolled Exposure(MPE}) . Frequency Range (MHz) Power Density (mWatts/cm**2) 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 (mWatts/cm**2) 30—300 1 .0 300—1500 Frequency (MHz) *(4.0/1200) 1500—100, 000 5 .0 Table 3 contains the parameters that are used to calculate the various power densities for the earth stations.

EXHILBIT A Page 2 of 5 Table 3. Formulas and Parameters Used for Determining Power Flux Densities Parameter Abbreviation Value Units Antenna Diameter D 5.6 meters Antenna Surface Area Sa IIL * D**2/4 meters*®*23 Subreflector Diameter Ds 54 .9 cm Area of Subreflector As IIL * Ds**2/4 cm**23 Frequency Frequency 14250 MHz Wavelength lambda 300 /frequency (MHz) meters Transmit Power P 123 .00 Watts Antenna Gain Ges 57 .0 dBi Pi II 3 . 1415927 n/a Antenna Efficiency n 0 .72 n/a 1. Far Field Distance Calculation The distance to the beginning of the far field can be determined from the following equation: (1) Distance to the Far Field Region, (Rf) = 0.60 * D**2 / lambda (1.} §93.8 meters The maximum main beam power density in the Far Field can be determined from the following equation: (2) On—Axis Power Dengity in the Far Field, (Wf} Ges * P / 4 * II * Rf**2 (2) 6.141 Watts/meters**2 0 .614 mWatts/cm**2 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 dGdecreases linearly with respect to increasing distance. The distance to the end of the Near Field can be determined from the following equation: (3) Extent of the Near Field, (Rn] D**2 / ({(4 * lambda) (3) IL =— 372.4 meters The maximum power density in the Near Field can be determined from the following equation: (4) Near Field Power Density, (Wn) 16.0 * n * P / II * D**2 (4) 14.336 Watts/meters**2 11 1.434 mWatts/em**2

EXHIBIT A Page 3 of 5 3. Transition Region Calculations 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: (5) Transition region Power Density, (Tt) Wn * Rn / Rt (5) = 1.434 mWatts/cm**2 4. Region between Main Reflector and 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 waveqguide 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: (6) Power Density at Feed Flange, (Ws) 4 * P / Asg (6) 208 .114 mWatts/cm*+*2 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: (7) Power Density at the Main Reflector Surface, (Wm) = 4 * P / Sa (7) = 19.976 Watts/meters*®*2 = 1.998 mWatts/cm**2 6. Region between Main Reflector and Ground Assuming uniform illumination of the reflector surface, the power density between the antenna and ground can be determined from the following equation: (8) Power Density between Reflector and Ground, (Wq) P Z Sa (8) 4.994 Watts/meters*®*2 0.499 mWatts/em**2

EXHILBIT A Page 4 of 5 Table 4. Summary of Expected Radiation levels for Uncontrolled Environment Calculated Maximum Radiation Power Density Level Region ({mWatts/cm**2) Hazard Assessment 1. Far Field (Rf) = 893.8 meters 0 .614 Satisfies FCC MPE 2. Near Field (Rn) = 372.4 meters 1 .434 Potential Hazard 3. Transition Region Rn < Rt < RFf, (Rt)] 1 .434 Potential Hazard 4. Between Main Reflector 208 .114 Potential Hazard and Subreflector 5. Main Reflector 1 .998 Potential Hazard 6. Between Main Reflector 0 .199 Satisfiles FCC MPE and Ground Table 5. Summary of Expected Radiation levels for Controlled Environment Calculated Maximum Radiation Power Density Level Region ({mWatts/cem**2) Hazard Assessment 1. Far Field (Rf) = 893.8 meters O .614 Satisfies FCC MPE 2. Near Field ({(Rn) = 372.4 meters 1 .434 Satisfies FCC MPE 3. Transition Region Rn < Rt < Rf, (Rt&) 1 . 434 Satisfies FCC MPE 4. Between Main Reflector 208 .114 Potential Hazard and Subreflector 5. Main Reflector 1 .998 Satisfies FCC MPE 6. Retween Main Reflector 0 .499 Satisfies FCC MPE and Ground It is the applicant‘s responsibility to ensure that the public and operational personnel are not exposed to harmful levels of radiation.

EXHIBIT A Page 5 of 5 7.— 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 . The antenna is mounted on a roof at an elevation of 25.9 meters above ground Level and since one diameter removed from the center of main beam the levels are down at least 20 dB, or by a factor of 100, public safety will be ensured for the near and far field regions. The antenna transmitter will be turned off during maintenance in order to comply with the FCC MPE limit of 5 mW/cem2 at the Reflector Surface.


Document Created: 2011-06-13 09:46:43
Document Modified: 2011-06-13 09:46:43
© 2024 FCC.report
This site is not affiliated with or endorsed by the FCC