Attachment 20161123131444.pdf

20161123131444.pdf

REQUEST FOR SUPPLEMENTAL INFORMATION submitted by FCC Staff Engineer

Rad Haz

2016-11-23

This document pretains to SES-STA-20161109-00879 for Special Temporal Authority on a Satellite Earth Station filing.

IBFS_SESSTA2016110900879_1159511

Exhibit B Radiation Hazard Report Analysis of Non—lonizing Radiation for a 8.1 m Earth Station This analysis provides the calculated non—ionizing radiation levels for a 8.1—meter earth station system. The methods and calculations performed in this analysis are based on the FCC Office of Engineering and Technology Bulletin, No.65, October1985 as 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 (Summarized in Annex 1). There are separate exposure limits applicable to the General Population/Uncontrolled Environment and the Occupational/Controlled Environment. The Maximum Permissible Exposure (MPE) limits for persons in a General Population/Uncontrolled environment for the frequency band of this antenna, is 1 mWi/icm2 for a 30 minute or lower time period as shown in Annex 1 (a). The MPE limit for persons in an Occupational/Controlled environment for the frequency band of this antenna is 5 mW/cm2 for a 6 minute time or lower period as shown in Annex 1 (b). The purpose of this analysis described is to determine the power flux density levels of the earth station at the main reflector surface, the near—field, transition region, far—field, between the sub—reflector or feed and, at the main reflector surface, and between the antenna edge and the ground and to compare these levels to the specified MPEs. The parameters of the antenna that is the subject of this analysis are shown in Table 1. intermediate calculated values and constants are provided in Table 2. Table 1. Input Parameters Used for Determining Power Flux Densities Parameter Symbol Formula Value Units Antenna Diameter D Input 8.1 m Sub—reflector Diameter Ds; Input 102.87 cm Frequency F Input 14250 MHz Transmit Power P Input 750 W Antenna Gain (dBi) Gaes Input 59.9 dBi Table 2. Calculated Values and Constants Parameter Symbol Formula Value Units Antenna Surface Area Asurtace t1D*/4 51.53 mA2 Area of Sub—reflector Asr nD,,/4 8311.27 cmA2 Wavelength A 300/F 0.021053 m Antenna Gain (factor) G 10%=*" 977237.22 wa Pi T Constant 3.1415927 wa Antenna Efficiency n GI(TD) 0.67 na

1. Antenna Main Reflector Surface The power density in the main reflector is determined from the Power level and the area of the main reflector aperture. This is determined from the following equation: Power Density at the Main Reflector Surface: Ssurfaca = 4P/Agurtace (1 ) = 58.219 W/im = 5.822 mWicm* 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 is determined from the following equation: Extent of the Near Field: Ry=D*/ (4A) (2) = 77912 m The maximum power density in the Near Field is determined from the following equation: Near Field Density: Sa = 16.0 1 P / (n D) (3) = 3.894 mWicm* 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 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 R, is determined from the following equation: Transition Region Power Density: S, = Su Rar/ Ri (4) = 3.894 mWicm*

4. Far Field Distance Calculation The distance to the Far Field Region is calculated using the following equation: Distance to Far Field Region: Ry =0.6 D/ A (5) = 1869.885 m The maximum main beam power density in the far field is determined from the following equation: On—axis Power Density in the Far Field: S,= GP / (4 m Ry*) (6) = 1.668 mW/(;m2 — 5. Region between the Main Reflector and the Ground Assuming uniform illumination of the reflector surface, the power density between the antenna and the ground is determined from the following equation: Power Density between Reflector and Ground: Sg =P /Asutface (7) = 1.455 mW/icm* 6. Power Density at the Sub—reflector Transmissions from the feed assembly are directed toward the sub—reflector surface, and are reflected back toward the main reflector. The most common feed assemblies are waveguide flanges, horns or sub—reflectors. The energy between the sub—reflector and the reflector surfaces is calculated by determining the power density at the sub—reflector surface. This is determined from the following equation: Power Density at the Subreflector: S,, = 4000 P / Ag, (8) = 360.956 mW/cm*

7. Summary of Calculations Table 3. Summary of Expected Radiation levels for Uncontrolled Environment Calculated Maximum Radiation H a Region Symbol Power azar Density Assessment Level (mWicm*) 1. Main Reflector ssurface 5.822 * Potential Hazard — 4 (Rm — 779.12 m) Sni 3.894 Potential Hazard 2. Near Field 3. Transition Region (R,; <R,< Rp) S, 3.894 P:;il;tlrgl 4 —= Potential 4. Far Field (R e 1869.89 m) Sr¢ 1.668 Hazard 5. Between Main Reflector and Subreflector Ss, 360.956 Potential Hazard 6. Between Main Reflector and Ground S 1.455 Potential Hazard Table 4. Summary of Expected Radiation levels for Controlled Environment Calculated Maximum Radiation H d Region Symbol Power azar Density Assessment Level ({mWicm*) . Ssurface 5.822 Potential Hazara 1. Main Reflector (R ns = 779.12 m) Sm 3.894 Satlsht;gsEFCC 2. Near Field S, 3.894 Satisht/ilgsEFCC 3. Transition Region (R,,; <R,< Rp) (Re= 1869.89 m) Sn 1.668 Satlshij"e:sEFCC 4. Far Field 5. Between Main Reflector and Subreflector Ss, 360.956 Pk?;iralflrgl 6. Between Main Reflector and Ground S, 1.455 Sat'sh';gfiEFCC It is the applicant‘s responsibility to ensure that the public and operational personnel are no exposed to harmful levels of radiation.

8. Conclusion Based upon the above analysis, it is concluded that harmful levels of radiation may exist in those regions noted for the Uncontrolled (Table 3) Environment and the Controlled Environment (Table 4). The antenna is located at an Intelsat License LLC‘s teleport facility in Napa, Califomia. The teleport is a gated and fenced facility with secured access in and around the proposed antenna. The earth station will be marked with the standard radiation hazard warnings, as well as the area in the vicinity of the earth station to inform those in the general population, who might be working or otherwise present in or near the direct path of the main beam. The applicant will ensure that the main beam of the antenna will be pointed at least one diameter away from any building, or other obstacles in those area that exceed the MPE levels. Since one diameter removed from the center of the main beam the levels are down by at least 20 dB, or by a factor of 100, these potential hazards do not exist for either the public, or for earth station personnel. Finally, the earth station‘s operating personnel will not have access to areas that exceed the MPE levels, while the earth station is in operation. The transmitter will be turned off during those periods of maintenance, so that the MPE standard of 5.0 mW/cm* will be complied with for those regions in close proximity to the main reflector, which could be occupied by operating personnel. "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.fec.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."

ANNEX 1 (MPE Levels) a) Limits for General Population/Uncontrolled Exposure (MPE) Frequency Ranfige (MHz) Power Density (mWIcmz, 30—300 0.2 300—1500 Frequency(MHz)*(4.0/1200) 1500—100,000 1 b) Limits for MPE F Power Dens mWi/icm 30—300 1 300—1500 Frequency(MHz)*(4.0/1200) 1500—100,000 §


Document Created: 2016-11-23 13:15:13
Document Modified: 2016-11-23 13:15:13
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