Attachment Exhibit 3

This document pretains to SES-MOD-20151102-00791 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2015110200791_1113410

EXHIBIT 3 RADIATION HAZARD STUDY (Response to Question 28) RADIATION HAZARD ANALYSIS 0.74 meter EARTH STATION This analysis calculates the non-ionizing radiation levels due to transmission from the earth station. The maximum level of non-ionizing radiation to which a person may be exposed corresponds to a power density of 10 Watts/sq.meter (or 1 mW/sq. cm) averaged over any thirty minute period, as derived from Standard C95.1 of the American National Standards Institute (ANSI). The analysis estimates the maximum power density levels in the vicinity of the antenna for six regions: near field; far field; transition zone; near the reflector surface; between the reflector and the ground; and between the feed mouth and the reflector. A brief discusion for each region is given below. The attached table shows the assumptions, formulae and calculations for all cases. 1. NEAR FIELD REGION The near field (or Fresnel region) is essentially an elliptical volume with its axis co-incident with the antenna boresight. The base of this volume is same as the aperture of the antenna. According to OST Bulletin No. 65, its length is equal to the square of the diameter divided by four times the wavelength. The larger dimension of the antenna (the width) is used in place of the diameter of a circular aperture as a worst case approximation. The maximum value of the on-axis power density is calculated using the equation given in the Bulletin by simply replacing the area of the circular aperture terms with the area of the elliptical aperture antenna. 2. FAR FIELD REGION The far field (or Fraunhofer region) extends outwards from a distance equal to 0.6 times the square of the reflector diameter divided by the wavelength, according to OST Bulletin No. 65. The larger dimension of the antenna (the width) is used in place of the diameter of a circular aperture. Power density varies inversely as the square of the distance. The maximum value of the power density is calculated using the equation given in the Bulletin. 3. TRANSITION REGION The transition region between the near field and the far field regions will have a power density that essentially decreases inversely as distance. In any case, the maximum power density will not exceed the maximum value calculated for the near field region, for the purpose of evaluating potential exposure. 4. REGION NEAR REFLECTOR SURFACE The power density in the region near the reflector surface can be estimated as equal to twice the power divided by the area of the reflector surface, assuming that the illumination is uniform and that it would be possible to intercept equal amounts of energy radiated towards and reflected from the reflector surface. 5. REGION BETWEEN REFLECTOR AND GROUND The power density in the region between the reflector and the ground can be estimated as equal to the power divided by the area of the reflector surface, assuming even illumination over the reflector. 6. REGION BETWEEN THE FEED MOUTH AND REFLECTOR The radiation from the feed is essentially confined to a conical region whose vertex is located at the feed mouth and extends to the reflector. Power density is maximum at the feed mouth, and can be estimated as twice the output power divided by the area of the feed mouth. The analysis shows that the power density levels will never exceed the ANSI limit even during periods of maximum output, except in the region between the feed and the reflector. To ensure compliance with the ANSI limit, the earth station transmitter will be turned off whenever maintenance and repair personnel are required to work within this potentially hazardous area.

RADIATION CALCULATIONS FOR 0.74 meter EARTH STATION Nomenclature Formula Value Unit INPUT PARAMETERS M = Antenna Aperture Major Axis 0.90 meters m = Antenna Aperture Minor Axis 0.62 meters w = Major Axis of Feed Mouth 0.045 meters h = Minor Axis of Feed Mouth 0.045 meters P = Max Power into Antenna 2.1 Watts n = Apperture Effeciency 67% k = Wavelength @ 30 GHz 0.0100 meters CALCULATED VALUES A = Area of Reflector PIxMxm/4 0.438 meters^2 l = Length of Near Field M^2/4k 20 meters L = Beginning of Far Field 0.6M^2/k 49 meters G = Antenna Gain @ 30 GHz n(4xPIxA)/k^2 36,903 (45.7) dBi a = Area of Feed Mouth PIxwxh/4 0.002 meters^2 POWER DENSITY CALCULATIONS Maximum Power Density in Region Region Hazard Assessment Formula Value (mW/cm^2 (FCC MPE Limit = 1 mW/cm^2) 1 Near Field 4nP/A 1.28 Potential Hazard 2 Far Field GP/(4(PI)L^2) 0.26 < FCC MPE Limit 3 Transition <= Nr Fld Region 1.28 Potential Hazard 4 Near Reflector Surface 4P/A 1.92 Potential Hazard 5 Between Reflector & Ground P/A 0.05 < FCC MPE Limit 6 Between Reflector and Feed 4P/a 528.2 Potential Hazard


Document Created: 2015-11-02 11:45:56
Document Modified: 2015-11-02 11:45:56
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