Attachment 2.4M RadHaz

This document pretains to SES-LIC-20120524-00471 for License on a Satellite Earth Station filing.

IBFS_SESLIC2012052400471_952880

Exhibit A Radiation Hazard Report Page 1 of 5 Analysis of Non-Ionizing Radiation for a 2.4-Meter Earth Station System This report analyzes the non-ionizing radiation levels for a 2.4-meter earth station system. The analysis and calculations performed in this r eport c omply with th e m ethods des cribed in t he F CC O ffice of Eng ineering 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 ar e in c onformance with the F CC R &O 96- 326. Bul letin N o. 6 5 an d th e FCC R&O specifies that there are two separate tiers of exposure limits that are dependant on the situation in which t he exposure t akes plac e a nd/or the s tatus of the individuals who ar e s ubject to the exposure. The Maximum Permissible Exposure (MPE) limits for persons in a G eneral Population/Uncontrolled environment are shown in Table 1. T he General Population/Uncontrolled MPE is a f unction of transmit frequency and is for an exposure per iod of thi rty m inutes or l ess. T he MP E l imits f or per sons in an O ccupational/Controlled environment are shown in Table 2. The Occupational MPE is a f unction of transmit frequency and is for an exposure period of six minutes or less. The purpose of the a nalysis described in this report is to determine the power flux density le vels of the earth s tation i n th e f ar-field, n ear-field, tr ansition r egion, 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 2.4 m Antenna Surface Area Asurface π D2 / 4 4.52 m2 Feed Flange Diameter Dfa Input 10.4 cm Area of Feed Flange Afa π Dfa 2/4 84.95 cm2 Frequency F Input 14250 MHz Wavelength λ 300 / F 0.021053 m Transmit Power P Input 100.00 W Antenna Gain (dBi) Ges Input 49.6 dBi Antenna Gain (factor) G 10Ges/10 91201.1 n/a Pi π Constant 3.1415927 n/a Antenna Efficiency η Gλ2/(π2D2) 0.71 n/a

Exhibit A 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) = 164.2 m The m aximum m ain beam pow er densit y in t he far field can be determined f rom t he f ollowing equation: On-Axis Power Density in the Far Field Sff = G P / (4 π Rff 2) (2) = 26.931 W/m2 = 2.693 mW/cm2 2. Near Field Calculation Power f lux densit y is consider ed to be at a maximum v alue throughout t he entire length of t he defined Near Field r egion. The region is con tained w ithin a cy lindrical v olume hav ing the sam e 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) = 68.4 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) = 62.869 W/m2 = 6.287 mW/cm2 3. Transition Region Calculation The Transition r egion is locat ed bet ween t he Near and Far Field r egions. The pow er density begins to decrease linear ly wit h incr easing distance in the Transition r egion. While the pow er density decreases inv ersely with dist ance in the Transition region, t he pow er densit y decr eases inversely with the square of the distance in the Far Field r egion. T he maximum power density in the Transition region will not exceed that calculated for the Near Field r egion. 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 t can be determined from the following equation: Transition Region Power Density St = Snf Rnf / Rt (5) = 6.287 mW/cm2

Exhibit A Radiation Hazard Report Page 3 of 5 4. Region between the Feed Assembly and the Antenna Reflector Transmissions from the feed assembly are directed toward the antenna reflector surface, and are confined w ithin a conical shape de fined by the type o f feed asse mbly. The most common f eed assemblies are waveguide flanges, horns or subreflectors. The energy between the feed assembly and r eflector su rface can be calculat ed by det ermining the pow er densit y a t the f eed assembly surface. This can be determined from the following equation: Power Density at the Feed Flange Sfa = 4000 P / Afa (6) = 4708.726 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 feed assembly. The area is now the area of the reflector aperture and can be determined from the following equation: Power Density at the Reflector Surface Ssurface = 4 P / Asurface (7) = 88.419 W/m2 = 8.842 mW/cm2 6. 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 Density between Reflector and Ground Sg = P / Asurface (8 ) = 22.105 W/m2 = 2.210 mW/cm2

Exhibit A 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 = 164.2 m) Sff 2. 693 Potential Hazard 2. Near Field (Rnf = 68.4 m) Snf 6. 287 Potential Hazard 3. Transition Region (Rnf < Rt < Rff) St 6. 287 Potential Hazard 4. Between Feed Assem bly and Sfa 4708. 726 Potential Hazard Antenna Reflector 5. Main Reflector Ssurface 8. 842 Potential Hazard 6. Between Reflector and Ground Sg 2. 210 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 = 164.2 m) Sff 2.693 Satisfies FCC MPE 2. Near Field (Rnf = 68.4 m) Snf 6. 287 Potential Hazard 3. Transition Region (Rnf < Rt < Rff) St 6. 287 Potential Hazard 4. Between Feed Assem bly and Sfa 4708. 726 Potential Hazard Antenna Reflector 5. Main Reflector Ssurface 8. 842 Potential Hazard 6. Between Reflector and Ground Sg 2.210 Satisfies FCC MPE

Exhibit A Radiation Hazard Report Page 5 of 5 8. Conclusions Based upon the above analysis, it is concluded that harmful levels of radiation may exist in those regions noted for the Uncontrolled (Table 4) and Controlled (Table 5) environments. The earth station will be installed on the roof of an 8' High Box Truck. Public access to the roof is restricted. The applicant will ensure that the main beam of the antenna will be point ed at least one diameter away from any buildings, or other obstacles in those areas that exceed the MPE levels. Since one diameter removed from the center of the main beam the levels are down at least 20 dB , or by a factor of 100, public safety will be ensured. The earth station will 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 may be working, or otherwise present on the roof, and in or near, the main beam of the antenna. Finally, occupational exposure will be lim ited, and the transmitter will be t urned off during periods of maintenance, so that the MPE standard of 5.0 mw/cm**2 will be complied with for those regions in close pr oximity t o t he m ain reflector, and sub reflector, which could be occupied by operating personnel.


Document Created: 2012-05-23 17:00:35
Document Modified: 2012-05-23 17:00:35
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