Attachment Exhibit B - RadHaz

This document pretains to SES-LIC-20100318-00330 for License on a Satellite Earth Station filing.

IBFS_SESLIC2010031800330_806315

Exhibit B - Universal Space Network C-Band FSS [RADIATION HAZARD REPORT] March 10, 2010 Form 312 Exhibit B Exhibit B Analysis of Non-Ionizing Radiation for a 3.8-Meter Earth Station System This report analyzes the non-ionizing radiation levels for a 3.8-meter C-band earth station system. This antenna is a prime focus aperture with no sub-reflector. The analysis and calculations performed in this report comply with the methods described in the FCC Office of Engineering and Technology Bulletin, No. 65 (oet65) first published in 1985 and revised in 1999 in 4th Edition. 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 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 3 contains the formulas and parameters used for determining the power flux densities. Frequency Range (MHz) Max Power Density (mW/cm2) 1500 – 100,000 1.0 Table 1. Limits for General Population/Uncontrolled Exposure (MPE) Frequency Range (MHz) Max Power Density (mW/cm2) 1500 – 100,000 5.0 Table 2. Limits for Occupational/Controlled Exposure (MPE) Page 1 of 5 Universal Space Network Antenna ID = HWI_GN01

Exhibit B - Universal Space Network C-Band FSS [RADIATION HAZARD REPORT] March 10, 2010 Parameter Symbol Formula Value Units Antenna Diameter D Input 3.8 meters Antenna Surface Area A surface D /42 11.34 meters2 Feed Aperture Area Aaperture R2 0.002565 meters2 Frequency F Input 6091 MHz Wavelength 300 / F 0.049253 meters Transmit Power P Input 2.5 Watts Antenna Gain (dBi) Ges Input 46.2 dBi Antenna Gain (scalar) G 10Ges/10 41686.9 n/a Pi Constant 3.1415927 n/a 2 2 2 Antenna Efficiency G /( D) 0.70 n/a Table 3. Formulas and Parameters Used for Determining Power Flux Densities Far Field Distance Calculation At the Far Field region the angular field distribution is essentially independent of the distance from the antenna, and the field has a predominantly plane-wave character and has a uniform distribution of electric and magnetic field strength. The power flux density now decreases inversely with the square of the distance. The distance to the beginning of the far field can be determined from the following equation: Distance to the Far Field Region . = 175.9 meters (1) The maximum flux power density in the far field can be determined from the following equation: On-axis power flux density ) (2) Where . 0.2680 W/m = 0.0268 mW/cm2 2 Near Field Calculation Power flux density is considered to be worse case 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 aperture. The distance to the end of the Near Field can be determined from the following equation: Extent of the Near Field = 73.3 meters (3) Page 2 of 5 Universal Space Network Antenna ID = HWI_GN01

Exhibit B - Universal Space Network C-Band FSS [RADIATION HAZARD REPORT] March 10, 2010 The maximum power density in the Near Field can be determined from the following equation: Near Field Power Flux Density . (4) 2 2 0.6172 W/m = 0.0617 mW/cm 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. The maximum power density in the Transition region will not exceed that calculated for the Near Field region. The power flux density in the Transition Region at distance can be determined from the following equation: Transition Region Power Density (5) Where the given distance Maximum power density 0.0617 mW/cm2 ( 73.3 meters) Directly in Front of Feed Assembly Calculation Transmissions from the prime focus feed assembly are directed out of the feed towards the main reflector aperture. This calculation is defined as the power density directly in front of and touching the feed assembly aperture, completely blocking and absorbing all power from the transmission out of the feed assembly to the main reflector. The power density at the feed assembly is determined by the following equation: Power Density at the Feed (6) 2 2 = 3898.3 W/m = 389.83 mW/cm Main Reflector Region Calculation Transmissions from the prime focus feed assembly are directed towards the main reflector aperture which in turn reflects the power towards the boresight axis of the antenna out into space. The power density in the reflector aperture is determined by the following equation: Power Density at the Reflector (7) 2 2 = 0.8818 W/m = 0.0882 mW/cm Page 3 of 5 Universal Space Network Antenna ID = HWI_GN01

Exhibit B - Universal Space Network C-Band FSS [RADIATION HAZARD REPORT] March 10, 2010 Region between the 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 Flux Density to Ground (8) 0.2204 W/m2 = 0.0220 mW/cm2 Summary of Calculations Tables 4 and 5 summarize the calculations of potential hazards. Calculated Maximum Power Flux Density Hazard Region Variable (mW/cm2) Assessment Far Field ( = 175.9 m) 0.0268 Satisfies FCC MPE Near Field ( = 73.3 m) 0.0617 Satisfies FCC MPE Transition Region ( 0.0617 Satisfies FCC MPE Table 4 Summary of Expected Radiation Levels for Uncontrolled Environment (1 mW/cm2 max) Calculated Maximum Power Flux Density Hazard Region Variable (mW/cm2) Assessment Far Field ( = 175.9 m) 0.0268 Satisfies FCC MPE Near Field ( = 73.3 m) 0.0617 Satisfies FCC MPE Transition Region ( 0.0617 Satisfies FCC MPE Feed Aperture 389.83 Potential Hazard Reflector 0.0882 Satisfies FCC MPE Between Reflector and Ground 0.0220 Satisfies FCC MPE Table 5 Summary of Expected Radiation Levels for Controlled Environment (5 mW/cm2 max) Page 4 of 5 Universal Space Network Antenna ID = HWI_GN01

Exhibit B - Universal Space Network C-Band FSS [RADIATION HAZARD REPORT] March 10, 2010 Conclusions Based on the analysis, it is concluded that the FCC RF Guidelines are exceeded only upon direct contact with the feed aperture as shown in table 5. This potential hazard could only occur in the controlled environment. Means of Compliance in Uncontrolled Areas No hazard exists in the uncontrolled environment due to the antenna is in a fenced secure location, and locked inside a radio transparent radome for weather protection. No uncontrolled person would have access to the antenna within a 10 meter distance without triggering security alarms. The only potential hazard requires a person to be directly in front of the feed horn radiating towards the reflector standing within the tripod structure that holds the feed horn in front of the reflector. Means of Compliance in Controlled Areas The potential hazard that exists in the controlled environment is the applicant’s responsibility to insure that operational personnel are not exposed to harmful levels of radiation. Appropriate RF hazard signage will alert operational personnel at the entrance to the antenna radome. The earth stations personnel will not have access to the area that exceeds the MPE levels while the earth station is in operation. The transmitters will be turned off during antenna maintenance. Page 5 of 5 Universal Space Network Antenna ID = HWI_GN01


Document Created: 2010-03-18 15:06:05
Document Modified: 2010-03-18 15:06:05
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