Attachment E000201

This document pretains to SES-MOD-20040429-00630 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2004042900630_373351

EXHIBIT 1 RADIATION HAZARD STUDY

EXH BIT 1 Page 1 of 6 ANALYSIS OF NON—IONIZING RADIATION FOR A 2.4 METER EARTH STATION This report analyzes the non—ionizing radiation levels for a 2.4 meter earth station. The Office of Engineering and Technology Bulleti n, No. 65, Edition 97—01, specifies that there are two separate tiers c f exposure limits that are dependent on the situation in which exposure t akes place and/or the status of the individuals who are subject to thd exposure. The Maximum Permissible Exposure (MPE) limit for persdq ns in a Uncontrolled/Public environment to non—ionizing radiation ove r a thirty minute period is a power density equal to 1 mW/cm**2 (one mill iwatts per centimeter squared). The Maximum Permissible Exposure (MPE) limit for persons in a Controlled/Occupational environment to non—ionizind radiation over a six minute period is a power density equal to 5 mW/d m**2 (five milliwatts per centimeter squared). It is the purpose of this report to determine the power flux densities of the earth station in the far field, near field, transition region, between the subreflector and main reflector surface, at the main reflector surface, and between the antenn a edge and the ground. The following parameters were used to calculate the various power flux densities for this earth station: Antenna Diameter, (D) = 2.4 meters Antenna surface area, (Sa) = pi (D**2) / 4 = 4 .52 m**2 Feed Flange Diameter, (Df) =— 1l1.4 cm Area of Feed Flange, (Fa) = pi (Df**2)/ 4 = 102}. 07 Wavelength at 14.2500 GHz, (lambda) = 0 .021 mecers Transmit Power at Flange, (P) = 500.00 Watts Antenna Gain, (Ges) Antenna Gain at = 8.91BE+04 14.2500 GHz = 49.5 dBi Converted to a Power Ratio Given By: AntilLog (49.5 / 10) pi, (pi) = 3.1415927 Antenna aperture efficiency, (n) = 0.55 1. Far Field Calculations The distance to the beginning of the far field region can be fou pd by the following equation: (1) Distance to the Far Field Region, (Rf) 0.60(D*x*2) / landa 164.2 m (1) Federal Communications Commission, Office of Engineering & Technology, Bulletin No. 65, pp. 17 & 18.

EXHIBIT 1 Page 2 of 6 The maximum main beam power density in the far field can be caldulated as follows: (1) On—Axis Power Density in the Far Field, (Wf) = (GES) (P) 4(pi) (RE**2) 131.59 W/m** 2 13.16 mW/cmL*2 2. Near Field Calculation Power flux density is considered to be at a maximum value throug hout the entire length of the defined region. The region is contaEged within a cylindrical volume having the same diameter as the ante a . Past the extent of the near field region the power density decre s es with distance from the transmitting antenna. The distance to the end of the near field can be determined by t he following equation: (1) Extent of near field, (Rn) = D**2 / 4 (lambda) = 68.40 m The maximum power density in the near field is determined by: (1 Near field Power Density, (Wn) 16.0(n)P mW/cm**2 pi(D**2) 243.15 W/m**2 24.32 mW/cm**2 3. Transition Region Calculations The transition region is located between the near and far regions. As stated above, the power density begins to decrea e with distance in the transition region. While the power density de reases inversely with distance in the transition region, the power decreases inversely with the square of the distance in the fa region. The maximum power density in the transition region wi 1 not exceed that calculated for the near field region. The power den ity in the near field region, as shown above, will not exceed 24 .32 wW/cm**2 . (1) IBID

EXH BIT 1 Pag 3 of 6 4. Region Between Feed Flange and Reflector Transmissions from the feed horn are directed toward the reflec or surface, and are confined within a conical shape defined by the feed. The energy between the feed and reflector surface can be calcul ted by determining the power density at the feed flange. This ca be accomplished as follows: Power Density at Feed Flange, (Wf) 4(P) / Fa 19594.33 mW/cm**2 5. Main Reflector Region The power density in the main reflector region is determined in the same manner as the power density at the feed flange, above, but the area is now the area of the reflector aperture: Power Density at Reflector Surface, (Ws) (4(P) / Sa) 442.10 W/m**2 44.21 mW/cm**2 6. Region between Reflector and Ground Assuming uniform illumination of the reflector surface, the ower density between the antenna and ground can be calculated as fol wS : Power density between Reflector and Ground, (Wg) = (P / Sa) = 110.52 W/ 11.05 mW m**2

EXHIJBIT 1 Page 4 of 6 Table 1 Summary of Expected Radiation Levels Based on (5 mW/cm**2) MPE for Controlled Environment Calculated Maximum Region Radiation Level (mW/cm**2) Hazard Assessment 1. Far Field, (Rf)= 164.2 m 13.16 POTENTIAL HAZAI’) 2. Near Field, (Rn)= 68.40 m 24 .32 POTENTIAL HAZARD 3. Transition Region, (Rt) 24 .32 POTENTIAL HAZARD Rn < Rt < Rf 4. Between Reflector 19594 .33 POTENTIAL HAZARD and feed Reflector Surface 44 .21 POTENTIAL HAZARD 6 Between Antenna 11.05 POTENTIAL HAZARD and Ground It is the applicants responsibility to ensure that the public and operational personnel are not exposed to harmful levels of radia Fion.

Table 2 Summary of Expected Radiation Levels Based on (1 mW/cm**2) MPE for Uncontrolled Environment Calculated Maximum Region Radiation Level (mW/cm**2) Hazard Assessment 1. Far Field, (Rf)= 164 .2 m 13 .16 POTENTIAL HAZARD 2. Near Field, (Rn)= 68 .40 m 24 .32 POTENTIAL HAZARD # 3. Transition Region, (Rt) 24 .32 Rn < Rt < Rf 4. Between Reflector 19594 .33 and feed 5. Reflector Surface 44 .21 POTENTIAL HAZARD 6. Between Antenna 11.05 POTENTIAL HAZARD and Ground It is the applicants responsibility to ensure that the public% and operational personnel are not exposed to harmful levels of radia ion.

EXHIBIT 1 Page 6 of 6 7. Conclusions Based upon the above analysis, it is concluded that FCC RF Guidelines have been exceeded in the specified region(s) of Tables 1 and 2. The applicant proposes to comply with the Mai kimum Permissible Exposure (MPE) limits of 1.0 mW/em**2 for the Uncontrolled Areas, and tht MPE limits of 5.0 mW/cm**2 for the Controlled Areas. It is concluded that harmful levels ofradiation will exist, but not in areas normally occupiefby the public, or the earth station‘s operating personnel. The antenna is mounted above the roof ofa truck, and the bottom lip of the dish will be at Ig ast 7.3 feet off the ground. The area around the antenna, equal to one diameter removed from the main beam will be rov| d off, and public access will be denied. This restricted area will be at least 10 feet around the =~. > a, and radiation hazard signs will be posted during the operation of this earth station. Since meter removed from the center of the main beam the levels are down at least 20 dB, or by 100, these potential hazards do not exist for either the public, or for earth station personn: The applicant will insure that the main beam of the antenna will be pointed at least one digmeter away from any buildings located within the far and near fields, and in the transition region. Since one diameter removed from the center of the main beam the levels are down at least 20 these potential hazards will not exist for either the public, or the earth station‘s operating persoi 1. Finally, the transmitter will be turned off during any antenna maintenance.


Document Created: 2004-05-18 15:26:39
Document Modified: 2004-05-18 15:26:39
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