Attachment Exhibit D

This document pretains to SES-LIC-20130418-00330 for License on a Satellite Earth Station filing.

IBFS_SESLIC2013041800330_993644

Exhibit D Page 1 of 5 DATE: February 20, 2013 SUBJECT: Radiation Hazard Analysis TO: FCC FROM: Michael J. Durbin Ph.D. E.E. Attached is the technical analysis that predicts the expected radio frequency radiation exposure to humans in the vicinity of the 2.4 Meter Satellite Up-Link Earth Station. The basis for this analysis was extracted from the following source: "Evaluating Compliance With FCC-Specified Guidelines for Human Exposure to Radio Frequency Radiation", OST Bulletin No. 65, October 1985, Federal Communications Commission, Office of Science and Technology, Washington, D.C. 20554 Please direct any questions to: Michael J. Durbin Ph.D. Mike.durbin@mci.com 214-801-7721

Exhibit D Page 2 of 5 EXHIBIT D RADIATION HAZARD ANALYSIS Prepared by: Michael J. Durbin Ph.D. Michael J. Durbin __________________________________

Exhibit D Page 3 of 5 RF RADIATION HAZARD ANALYSIS 2.4 METER SATELLITE UP LINK EARTH STATION Because of the highly directional nature of parabolic antenna systems, the possibility of significant Human exposure to RF radiation is unlikely if precautions are taken to prevent incidental human access to those few areas where the existing power densities are in excess of those recommended for Human Exposure1. There are regions in the vicinity of the antenna that can generate substantial power density levels, such as the area between the feed and the sub reflector and the area directly in front and along the axis of the antenna. The antenna site layout is designed to limit the access to these areas. Therefore, the earth station operators and the general public will only be exposed to microwave radiation levels below and behind the antenna, and at various orientations off from the main axis of the antenna. The predicted radiation exposure levels are calculated below. They show that operations personnel and the general public will be exposed to radiation levels below the recommended values of 5 mw/cm2 for short term or 1 mw/cm2 for long term exposure. The particular site parameters used in the analysis are as follows: D = antenna diameter = 2.4 Meter F = frequency = 6125 MHz.  = wavelength = .048980 P = power into the feed = 200 Watts (max)  = Pi = 3.1416  = physical aperture area(D2/4 = 4.53 Sq. Meters G = antenna transmit gain = 18770.6 = 42.735 dBi  = aperture efficiency = 0.67 NEAR FIELD REGION With a parabolic antenna the power density is greatest on the antenna axis in the near-field region of the antenna. This maximum occurs at a distance of 0.2 D2/ = 130.055 Meters ( 426.5804 feet) from the antenna, however, conservatively, we consider that this maximum power density value occurs throughout the length of the near field region R, where R is as follows: R = D2/4 = 23.52 Meters (77.145 feet) 1 "Evaluating Compliance With FCC-Specified Guidelines for Human Exposure to Radiation Frequency Radiation", OST Bulletin No. 65, October 1985, Federal Communications Commission, Office of Science and Technology, Washington, D.C. 20554

Exhibit D Page 4 of 5 The power density within this region is equal to the following: PD = (16P)/(D2) = (4P)/A = 118.442979 W/m2 = 11.844298mW/cm2 TRANSITION REGION: The power density in the transition region decreases inversely with distance from the antenna. For evaluating exposure in this region the distance to the beginning of the near field region is determined as follows: R = (0.6D2) = 29.4 Meters (96.432 feet) The on-axis power densities in the transition region can be estimated as follows: PD(trans) = (PD(near field)R(near field))/R Where R is the point of interest. The on-axis power density energy in both these regions is contained within a cylindrical volume of a diameter equal to the antenna's diameter and extends upward into space according to the antenna's elevation angle. Because of the elevated geometry of the main reflector and the rising edges of the cylindrical near field region of the antenna both these areas will be inaccessible by the public or personnel. Off axis calculations in the near field and in the transition region can be made assuming a point of interest at least one antenna diameter from the center of the antenna main beam. The power density at that point will be at least a factor of 100 (20 dB) less than the value calculated for the equivalent distance in the main beam. Therefore, it maybe assumed that the power density will be at least 20 dB below the maximum level at a radial distance of D, 2.4 meters, from the center line axis of the antenna. At distances within the near field radiation density will be: 11.844298 mW/cm2/100 = ..11844298 mW/cm2 (and less for the transition region) FAR FIELD REGION In the far field region, the power is distributed in a pattern of maxima and minima (sidelobes) as a function of the off-axis angle between the antenna center line and the point of interest. The on-axis power density in the far field is as follows: PD = (PG)/4R2 = 55.185499 M/W2 = 5.518550 mW/cm2 The above value represents the maximum exposure level that the system can produce on-axis. Off-axis power densities will be considerably less (typically in excess of 30 dB at angles of one degree or more from beam center). Therefore , far field exposure will be less than: PD = 5.518550/300 = 0.005519 mW/cm2

Exhibit D Page 5 of 5 BEHIND AND BELOW For areas behind and below the antenna structure, where station personnel and working environment exist, the radiation level will be less than the tapered illumination level of the main reflector. This level is as follows: PD (radiation level) < or = the transmitter power, P, divided by the area of the antenna reflector less a 6 dB taper factor. = 11.048785W/M2 = 1.104879 mW/cm2. This value would be expected directly at the edge of the main reflector, therefore, levels several feet below and behind the reflector would be even further reduced in level. We conclude then, the area around the antenna that can be accessed by station personnel will exhibit a radiation level slightly above the recommended 1 mW/cm2 level. However actual access to the antenna system is restricted to authorized trained personell only, and only for short time durations. The actual operations personell are located in a steel building which provides more than adequate shielding for the long term operations. In conclusion, no radiation hazard in excess of the recommended long term of 1 mW/cm2 or short term exposure level of 5 mW/cm2 will present a threat to the general public nor the earth station personnel.


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Document Modified: 2013-03-19 14:15:48
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