Correction to SES-MO

SUPPLEMENT submitted by AT&T Corp.

Correction

2019-03-25

This document pretains to SES-MOD-20180821-02252 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2018082102252_1639756

Daniel P. Brooks 202.719.4183 dbrooks@wileyrein.com VIA ELECTRONIC FILING March 25, 2019 Marlene H. Dortch Office of the Secretary Federal Communications Commission 445 12th Street, SW Washington, DC 20554 Re: AT&T Corp. Modification of Call Sign E980066 to Replace Antenna, Add Ku‐Band Frequencies, and Correct Geographic Coordinates, SES‐MOD‐20180821‐02252 Dear Ms. Dortch: AT&T Corp. (“AT&T”), by its undersigned counsel, respectfully submits this correction to the above‐captioned earth station modification application. Specifically, AT&T requests that the data currently provided in the application for Schedule B Items E38, E40, E48, E49, and E56‐E59 be replaced with the data in Tables 1, 2, and 3 below for the specified frequency bands (where applicable): Table 1: Total Input Power and Total EIRP E38. Total Input Power at E40. Total EIRP for All Antenna Flange (Watts) Carriers (dBW) 400.0 86.0 Table 2: EIRP and EIRP Density Frequency Bands (MHz) E48. Maximum EIRP per E49. Maximum EIRP Density Carrier (dBW) per Carrier (dBW/4kHz) 5850‐5925 78.27 38.37 5925‐6425 78.47 38.57 13750‐14000 84.67 45.11 14000‐14500 84.87 45.31 1776 K Street NW | Washington, DC 20006 | 202.719.7000 wileyrein.com

Marlene H. Dortch, Secretary March 25, 2019 Page 2 Table 3: Elevation and Azimuth1 Frequency E57. Antenna E59. Antenna E56. Earth E58. Earth Bands (MHz) Elevation Angle Elevation Angle Station Azimuth Station Azimuth Eastern Limit Western Limit Angle Eastern Angle Western Limit Limit 3625‐4200 8.6 257.9 10750‐11700 9.4 257.3 11700‐12200 25.1 9.4 116.1 257.3 13750‐14000 15.2 252.8 14000‐14500 15.2 252.8 An updated radiation hazard study to account for the change to the antenna’s total input power is attached as Exhibit A. Finally, AT&T seeks to replace all points of communications listed under the current authorization with “Permitted Space Station List” satellites only. Please do not hesitate to contact the undersigned should you have any questions. Respectfully Submitted, /s/ Daniel P. Brooks Daniel P. Brooks Counsel for AT&T Corp. 1 A shaded cell indicates no change to the data currently provided in the application. 1776 K Street NW | Washington, DC 20006 | 202.719.7000 wileyrein.com

Exhibit A Radiation Hazard Study

Radiofrequency (RF) Radiation Hazard Study 9.0-meter Antenna This report summarizes the non-ionizing radiofrequency (RF) exposure levels associated with the above antenna system. RF prediction models and associated exposure limits referenced in this study are outlined in the Federal Communications Commission (FCC) Office of Engineering and Technology (OET) Bulletin 65 Edition 97-01 (August 1997). The FCC-exposure limits define the level of RF energy that a person may be continuously exposed without experiencing adverse health effects. This "safe" level, herein referred to as Maximum Permissible Exposure (MPE) limit, is comprised of two-tiers: one for conditions which the public may be exposed (General Population/Uncontrolled) and the other for exposure situations usually involving workers (Occupational/Controlled). Therefore, the intent of this study is to define the maximum "worst-case" RF exposure levels and compare the results relative to the applicable MPE limits. Based upon the following system parameters, the applicable MPE limits are: 1.0 mW/cm^2 and 5.0 mW/cm^2 for General Population/Uncontrolled and Occupational/Controlled environments, respectively, as specified in 47 CFR Part 1.1310. System Parameters Antenna Diameter (D1): 9.0 meters Antenna Surface Area (D1a): 63.62 meters^2 Subreflector Diameter (D2): 1.20 meters Subreflector Surface Area (D2a): 1.13 meters^2 Operating Frequency: 14250 MHz Wavelength (): 0.021 meters Antenna Gain (G), @ 6125 MHz: 60.1 dBi Numerical Gain: 1023292.99 Transmit Power @ Antenna Input*: 400.0 watts Calculated Aperture Efficiency (n ): 0.57 Center height above ground level: 4.5 meters * Based on an 800 W maximum power rated amplifier, where the actual operating power level will be reduced by at least a factor of 2.0 (3 dB minimum output backoff, transmission loss, etc.). For purposes of study, this equates to an aggregate output EIRP for all carriers of 86.12 dBW maximum. Hazard Assessment For parabolic aperture antennas, three (3) regions are defined for predicting maximum RF exposure levels within the main-beam (on-axis) path: near-field, transition, and far-field regions. RF prediction methods are based on where the point-of-interest falls within these regions: 1. The far field (Rff) region is determined by the following equation: 0.6 D^2/  This equates to a linear distance of approximately 2308.50 meters from the antenna. The maximum main beam RF exposure level (Sff), in terms of power density units, at this point can be calculated as follows: Sff = PG / 40 (Rff)^2 = 0.61 mW/cm^2 2. The near field (Rnf) region is determined by the following equation: D^2/ 4 This equates to a linear distance of approximately 961.88 meters from the antenna. The maximum RF exposure level (Snf), in terms of power density units, within this region can be calculated as follows: Snf = 0.4n P/ D1a = 1.43 mW/cm^2 (Assume maximum value maintained throughout the near field region) ** The transition (Rt) region is between the near-field and far-field regions, defined as Rff - Rnf. This equates to a region extending 1346.63 meters, beginning at 961.88 meters and ending 2308.50 meters from the antenna. While the exposure intensity decreases inversely with the square of the distance in the Page 1 of 3

Radiofrequency (RF) Radiation Hazard Study - Continued 9.0-meter Antenna Hazard Assessment - Continued far field region, the exposure intensity decreases inversely with distance in the transition region. Therefore, the maximum RF exposure level in the transition region will not exceed the above calculated near field value (Snf). If the point-of-interest falls within the transition region, the estimated RF exposure level (St), in terms of power density units, can be calculated using the following mid-point (Rt) example: St = Snf * Rnf / R = 0.84 mW/cm^2 - at mid-point of Rt note: where 'R' is the point-of-interest within the Rt This dual-reflector (cassegrain) antenna design uses a shaped subreflector to direct RF energy from the feed horn back towards the main reflector dish. The following calculations are used to predict the RF exposure levels directly in front of the main reflector surface (rim), and regions between the main reflector and subreflector surfaces: 3. The maximum RF exposure level (Smain-surface) in front of the main reflector surface (at rim), in terms of power density units, can be calculated as follows: Smain-surface = 0.4*P / D1a = 2.52 mW/cm^2 4. The maximum RF exposure level at the subreflector surface (Ssub-surface), in terms of power density units, can be calculated as follows: Ssub-surface = 0.4*P / D2a = 141.47 mW/cm^2 For evaluating accessible areas outside the main beam path, a practical estimation is to consider the maximum allowable gain pattern envelope for fixed-satellite services. Specifically, the antenna gain shall lie below the envelope defined as -10 dBi for angles greater than 48 degrees and less than/equal to 180 degrees from the main lobe axis. In considering areas immediately below the main reflector rim, the maximum RF exposure levels directed towards this region (Spoi), in terms of power density units, can be calculated as follows: 5. Spoi = PG/40 (R)^2 = 0.016 mW/cm^2 Note : where 'R' is the point-of-interest is just below antenna rim, which equates (in this case) to a centerline distance: 4.5 meters Page 2 of 3

Radiofrequency (RF) Radiation Hazard Study - Continued 9.0-meter Antenna Hazard Assessment - Summary Summary of Calculated RF Exposure Levels Region Level (mW/cm^2) Assessment A. Far Field (Rff), 2308.50 meters, = 0.61 Satisfies FCC MPE Limits B. Near Field (Rnf), 961.88 meters, = 1.43 Potential to exceed FCC Public/Uncontrolled MPE Limit C. Rim of Main Reflector = 2.52 Potential to exceed FCC Public/Uncontrolled MPE Limit D. Subreflector = 141.47 Potential to exceed FCC Occupational MPE Limit E. Area below Antenna Rim = 0.016 Satisfies FCC MPE Limits C D Rim of Main Subreflector A Reflector Far Field B Near Field Feed Horn E Area Below Antenna Rim Conclusion The results of this study indicate that accessible ground level areas, surrounding the antenna base and horizontal to the main beam axis, do not exceed the most restrictive FCC-General Population/Uncontrolled MPE limit. The highest RF exposure levels are isolated to regions located between the feed horn and subreflector surface, which are typically inaccessible during normal operations. To ensure compliance with the FCC Occupational/Controlled MPE limit, these areas shall be controlled (restricted access) and the antenna system de-energized during any maintenance/service activities occurring within the main reflector or subreflector regions. This study concludes that operation of this satellite earth station will not expose workers or public members to RF levels in excess of the applicable MPE limits. Therefore, in accordance with 47 CFR Part 1.1307 (b), preparation and submission of an Environmental Assessment (EA) is not required. Performed by: Navid Motamed Date: March 19 2019 Phone No. 310 964 3589 Page 3 of 3


Document Created: 2019-03-25 13:48:04
Document Modified: 2019-03-25 13:48:04
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