Attachment Exhibit B

This document pretains to SES-MOD-20101203-01496 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2010120301496_854992

ANALYSIS OF NON—IONIZING RADIATION FOR A 3.6 METER EARTH STATION Completed 11/15/2010 This report analyzes the non—ionizing radiation levels for a 3.6 meter earth station. 1t is the purpose ofthis report to determine the power flux densities ofthe earth station at the antenna surface. near field, far field, and the transition region. Results are summarized in Table 1 on page 4. The Office Engineering & Technology Bulletin, No. 65. August 1997, specifies the following Maximum Permissible Exposure (MPE} levels for non—ionizing radiation : 1. QOccupational/Controlled Exposure is Sm W/em? (five milliwatts per centimeter squared) over an average time of 6 (six) minutes, 2. General Population/Uncontrolied Exposure is 1m W/em? (one milliwait per centimeter squared) over an average time of 30 (thirty) minutes. The following parameters were used to calculate the various power flux densities for this earth station: Location: Platinum, Alaska Latitude: 59.012444 °N Longitude: 161.817278 °w Operating Frequency: 6175 MHz Wavelength (A) 0.0485 meters Antenna Diameter (D): 3.6 meters Antenna Area (A): 10.18 meters* Transmit Antenna Gain: 45.6 dBi Transmit Antenna Gain (G): 36307.8 numeric 1° Off Axis Gain 29.0 dBi 1° Off Axis Gain (G;—) 794.3 numeric Antenna Efficiency (n): 0.669 numeric Feed Power (P): 200 Watts Page 1 of

1. Antenna Surface The power density in the main reflector region can be estimated by: Power Density at Reflector Surface, Suutice~ 4P/A 78.60 W/im‘ t 7.86 mW/cm‘ n Surre:= maximum power density at antenna surface P= power fed to the antenna A= physical area of the antenna 2. Near Field Calculations In the nearfield region, of the main beam, the power density can reach a maximum before it begins to decrease with distance. The magnitude of the on axis (main beam) power density varies according to location in the near—field. The distance to the end of the near field can be determined by the following equation: Extent of Near Field, R.= DVA(A) = 66.74 meters R.,= extent of near field D= maximum dimension of antenna (diameter if circular) A= wavelength The maximum near—field, on—axis, power density is determined by: On Axis Near Field Power Density, S,.= 16nPD*r = §2.58 W/in* = 5.26 mW/cm‘ The maximum near—field, 1 ° off—axis. power density is determined by: Power Density at 1° Off Axis Sy u* (64/G)*G; = 0.1150 mW/em? S.,~ maximum near—field power density Sori«= maximum near—field power density (1° off axis) 1= aperture efficiency P= power fed to antenna D= maximum dimension of antenna (diameter if circular) Page 2 of 4

3. Far Field Calculations The power density in the far—field region decreases inversely with the square of the distance. The distance to the beginning ofthe far field region can be found by the following equation: Distance to the Far Field Region, Ry= 0.6D% = 160 meters Rg= distance to beginning of far field D= maximum dimension of antenna (diameter if circular) A= wavelength The maximum main beam powerdensity in the far field can be calculated as follows: On—Axis Power Density in the Far Field. Sy= (PXG)An(Re)* = 22.53 W/im* = 2250 mW/ca‘ The maximum far—field, 1 ° off—axis, power density is determined by: Power Density at 1° Off Axis Sf|.= (SMG)*G,— = 0.0493 mW/cm‘ Sa= power density (on axis) Sff |«= power density (1° off axis) P= power fed to antenna G= power gain of antenna in the direction of interest relative to an isotropic radiator Ry= distance to beginning offar field 4. Transition Region Calculations The transition region is located between the near and far field regions. The power density decreases inversely with distance in the transition region, while 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 in the near field region, as shown above will not exeeed: S~ 5.26 mW/em‘. S,,+= 0.1150 mW/em?. Page 3 of 4

Table Summary of Expected Radiation Levels Calculated Maximum Maximum Permissible Exposure (MPE) Region Radiation Level (mW/em) Occupational General Population 1. Antenna Surface Suutace® 786 Potential Hazard Potential Hazard 2. Near Field S 5.26 Potential Hazard Potential Hazard 3. Far Field Sy~ 2.25 Satisfics MPE Potential Hazard 4. Transition Region S,= 5.26 Potential Hazard Potential Hazard 5. Near Field 1° Off Axis Siri= 0.1150 Satisfies MPE Satisfies MPE 6. Far Field 1° Off Axis Sff)«= 0.05 Satisfies MPE Satisfies MPE 7. Transition Region 1° Off Axis $,,«= 0.1150 Satisfics MPE Satisfies MPE 7. Conclusions Based on the above analysis it is concluded that the only risk of exposure to levels higher than the Maximum Permissible Exposure limit are at the surface ofthe antenna, in the near—field of the main beam, and in the transition region of the main beam. At 1. off axis the radiation levels are well within limits. A 5 minimum elevation angle and a fence surrounding the facility will protect the public from exposure to high radiation levels. The transmitter will be turned off during antenna maintenance and the 5 minimum elevation angle will ensure safety of the earth station personnel. Sunil Panthi RF Engineer I GCI Communication Corp. Page 4 of 4


Document Created: 2010-12-02 15:12:28
Document Modified: 2010-12-02 15:12:28
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