Response re ViaSat-2

SUPPLEMENT submitted by ViaSat, Inc.

Response to IB Information Request

2016-09-09

This document pretains to SAT-MOD-20160527-00053 for Modification on a Satellite Space Stations filing.

IBFS_SATMOD2016052700053_1148796

555 Eleventh Street, N.W., Suite 1000 Washington, D.C. 20004-1304 Tel: +1.202.637.2200 Fax: +1.202.637.2201 www.lw.com FIRM / AFFILIATE OFFICES Barcelona Moscow Beijing Munich Boston New Jersey Brussels New York Century City Orange County September 9, 2016 Chicago Paris Dubai Riyadh Düsseldorf Rome VIA ELECTRONIC FILING IN IBFS Frankfurt San Diego Hamburg San Francisco Hong Kong Shanghai Ms. Marlene H. Dortch Houston Silicon Valley London Singapore Secretary Los Angeles Tokyo Federal Communications Commission Madrid Washington, D.C. 445 12th Street, SW Milan Washington, DC 20554 Re: ViaSat, Inc., IBFS File No. SAT-MOD-20160527-00053, Call Sign S2902 Dear Ms. Dortch: ViaSat, Inc. (“ViaSat”) responds to the Commission’s request dated August 15, 2016 for additional information regarding the above-referenced application seeking to modify its grant of U.S. market access for the ViaSat-2 satellite at the 69.9º W.L. orbital location to add the 27.5- 28.1 GHz and 17.7-18.3 GHz frequencies. The attached Attachment A provides the technical information and analyses requested. If you have any questions regarding this submission, please contact the undersigned. Respectfully submitted, /s/ John P. Janka Elizabeth R. Park Attachment cc: Jose Albuquerque Stephen Duall Alyssa Roberts

ATTACHMENT A RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION Engineering Analysis and Supporting Technical Information REQUEST ONE: For the frequency band 17.7-17.8 GHz (space-to-Earth) please provide the predicted transmitting antenna off-axis gain information specified in Section 25.264(a) of the Commission’s rules, 47 CFR § 25.264(a). In addition, please perform the power flux-density (pfd) calculations based upon this off-axis antenna gain information as specified in Section 25.264(b) and identify each prior-filed U.S. Direct Broadcast Satellite (DBS) space station at whose location the coordination threshold pfd level of -117 dBW/m2/100 kHz is exceeded. Although ViaSat considers the 61.5º W.L. ITU Region 2 Broadcasting-Satellite Service (BSS) Plan location in its application, its pfd calculations must take into account all prior-filed U.S. DBS space stations as defined in Section 25.264(b)(1). Figures 1 and 2 below provide the requested transmitting off-axis gain information for the A type and B type spot beams. The beams are circular and symmetric about the Z axis. In addition to the 61.7° W.L. orbital position considered in ViaSat’s technical annex, two other DBS networks that use the 17.7-17.8 GHz band segment and that have U.S. market access are operated within the vicinity of the nominal 70° W.L. orbital location: NIMIQ 5 at 71.7° W.L., and Quetsat at 77.0° W.L. The geocentric angle between ViaSat-2 at 69.9° W.L. and each of the former locations is 8.1°, 1.9°, and 7.2° respectively. In the X axis, the off-axis angle toward each of the potential victim satellites is in the range of 85.95° to 89.05°. Examining Figures 1 and 2 shows that for an off-axis angle between 85° and 90° the gain is reduced by approximately 100 dB for the A type beam and by approximately 80 dB for the B type beam. The distance between ViaSat-2 and each of the potential victim satellites ranges between 1397.9 km for the closest satellite and 5954.8 km for the farthest satellite. The associated spreading loss values for the two distances are 133.9 dB(m2) and 146.5 dB(m2). 1

Assuming the higher EIRP density of 39.5 dBW/MHz for the A type beam, the minimum spreading loss of 133.9 dB(m2), and a conservative 80 dB of off-axis gain reduction, the worst case pfd at any of the potential victim satellite locations is -184.4 dB(W/(m2 * 100 kHz)). As shown in the calculation in Table 1 below, this is approximately 67.4 dB lower than the coordination threshold pfd level of -117 dB(W/(m2 * 100 kHz)). Figure 1 A Type Gain Plot 2

Figure 2 B Type Gain Plot 3

Table 1 RDBS PFD Calculation Results 4

REQUEST TWO: Please provide an interference analysis as described in Section 25.140(b)(4)(iii) of the Commission’s rules, 47 CFR § 25.140(b)(4)(iii), demonstrating that ViaSat’s proposed operations in the 17.7-17.8 GHz (space-to-Earth) band will not cause more interference to any current or future 17/24 GHz BSS satellite networks than if the applicant were located at the precise Appendix F orbital location from which it seeks to offset. ViaSat’s orbital location, 69.9º W.L., is offset 1.1 degrees from the 71º W.L. Appendix F orbital location. Accordingly, ViaSat’s operations from this location must be at pfd levels that are reduced from those specified in Section 25.208(c) in accordance with the following calculation methodology: For a given location on the surface of the Earth at which the required pfd reduction value needs to be determined, calculate the topocentric angular separation ‘ϕ’ of the 71º W.L. and 67º W.L. geostationary orbital locations, and the corresponding off-axis gain GCO1(ϕ) of the antenna specified in Section 25.224(a)(1) of the Commission’s rules at that angular separation. For the same location on the surface of the Earth, also calculate the topocentric angular separation of the 67º W.L. and 69.9 º W.L. geostationary orbital locations, and the gain of the antenna GCO2(ϕ) specified in Section 25.224(a)(1) of the Commission’s rules at that angular separation. Then, perform the subtraction GSO2(ϕ) – GCO1(ϕ). The result is the required reduction in pfd from the value specified in Section 25.208(c). Please demonstrate that under all atmospheric conditions, and for all angles of arrival, the pfd levels at the Earth’s surface from ViaSat’s transmissions in the 17.7-17.8 GHz (space-to-Earth) band will not exceed these calculated levels anywhere within the United States and its Territories. The following interference analysis demonstrates that ViaSat’s proposed operations in the 17.7- 17.8 GHz (space-to-Earth) band will not cause more interference to any current or future 17/24 GHz BSS satellite networks than if the applicant were located at the precise Appendix F orbital location from which it seeks to offset. ViaSat’s orbital location of 69.9° W.L. is 1.1° offset from the 71.0° W.L. and accordingly that much closer to the 67.0° W.L. orbital location. Table 2 below identifies the topocentric separation angle between the 71° W.L. and 67° W.L. orbital locations and the topocentric separation angle between the 67° W.L. and 69.9° W.L. orbital locations. Table 2 also includes the corresponding off-axis co-polar pattern gain values calculated for the reference antenna for each of the two topocentric angles. The difference in the two gain values is the amount by which ViaSat’s pfd at that location of interest must be reduced from the value specified in Section 25.208(c). ViaSat determined the above values for the NW, SW, NE, and SE corners of the U.S., as well as Puerto Rico. In Table 2, the resulting values are shown, demonstrating that the pfd levels from ViaSat-2 at the 69.9° W.L. meets the required pfd limit (as reduced to account for the relevant 5

topocentric angles) at all locations within the United States and territories for both type spot beams. Therefore, operations of ViaSat-2 in the 17.7-17.8 GHz band segment at the 69.9° W.L. orbital location will not cause more interference to any current or future 17/24 GHz BSS satellite networks than if the satellite were located at the 71° W.L. orbital location. Table 2 DBS PFD Calculation Results 6



Document Created: 2016-09-09 13:35:39
Document Modified: 2016-09-09 13:35:39
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