Attachment Narrative

This document pretains to SES-LIC-INTR2018-04088 for License on a Satellite Earth Station filing.

IBFS_SESLICINTR201804088_1468320

MICROWAVE PATH SURVEY REPORT RADIO FREQUENCY INTERFERENCE (RFI) MEASUREMENT REPORT Prepared For ViaSat West Bridgewater (Boston), Massachusetts Transmit and Receive Earth Station 17-21 GHz and 27-31 GHz JANUARY 31, 2018 19700 Janelia Farm Boulevard. - Ashburn, Virginia 20147, USA - 703.726.5500 - Fax 703.726.5597

TABLE OF CONTENTS SECTION 1 Introduction and Background 1.1 Introduction 1.2 Background 1.3 Constraints SECTION 2 Test Procedure 2.1 Calibration 2.2 Methodology SECTION 3 Data Presentation SECTION 4 Summary of Results SECTION 5 Conclusions and Recommendations 5.1 Conclusions 5.2 Recommendations Addendum 1 Addendum applicable to this report showing spectral plots for one possible interference case as identified in the office study.

SECTION ONE

SECTION 1 INTRODUCTION AND BACKGROUND 1.1 Introduction On-site Radio Frequency Interference (RFI) measurements were performed on behalf of ViaSat, Inc. on JANUARY 31, 2018 at their proposed site in West Bridgewater (Boston) Massachusetts. The purpose of these measurements was to determine the relative RFI levels in the 17-21 and 27-31 GHz common carrier frequency band and their impact on digital down-link satellite reception. Measurements were performed at one designated location. The purpose of this report is to document the results of these measurements and to present recommendations. The analysis in this report is based upon the following: • Andrew 4.1 Meter Antenna • Satellite Arc: 55 to 115 Degrees West Longitude • Frequency Range Considered: 17 to 21 GHz and 27-31 GHz • Interference Objective: -156 dBW/1 MHz • Type of Reception: Digital • Measured Antenna Center Line: 6.5 Feet Above Ground Level 1.2 Background ViaSat, Inc is proposing to locate a new transmit/receive antenna at an existing location of 420 1’ 46.6” N and 710 0’ 26.4” W ViaSat, Inc had requested that Comsearch conduct RFI measurements at the facility to assess the interference potential. This facility is currently nonoperational and measurements were done at a point near the proposed antenna locations. The measured site is identified on a portion of a topographic map shown in Figure 1.2-1. An aerial photo of the site location is shown in Figure 1.2-2. A photo of the measurement using a GPS is shown in Figure 1.2-3.

1.3 Constraints The analysis in this report is based upon the following assumptions and constraints. • The antenna selected will conform to the FCC reference pattern 32-25 Log as specified in 47CFR 25.209(a)(2). • It is assumed that during the measurement period all of the terrestrial transmitters were active and operating at full transmit power for the licensed frequencies unless otherwise noted. • The signal identification and frequencies analyzed are based upon information obtained from the various common carriers as to what frequencies were active at the time of the measurements and the traffic these frequencies were supposed to be carrying. • The actual ground elevation of the site is based on the data from the topographic map. • The interference objective of –156 dBW/1 MHz used throughout this report is based upon estimated link budget parameters and is subject to change. ViaSat, Inc should review the system parameters for this down-link in order to verify the viability of this objective.


Document Created: 2018-07-20 14:13:25
Document Modified: 2018-07-20 14:13:25
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