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CCL00427 RF Compliance Report 01072021AT&T Mobility • Base Station No. CCL00427 10655 Mary Avenue • Cupertino, California FA No. 10095955, USID No. 13272 X4LL Page 1 of 3 ©2021 Statement of Hammett & Edison, Inc., Consulting Engineers The firm of Hammett & Edison, Inc., Consulting Engineers, has been retained by AT&T Mobility, a wireless telecommunications carrier, to evaluate its existing base station (Site No. CCL00427) located at 10655 Mary Avenue in Cupertino, California, for compliance with appropriate guidelines limiting human exposure to radio frequency (“RF”) electromagnetic fields. Executive Summary AT&T had installed directional panel antennas on a tall pole at 10655 Mary Avenue in Cupertino. All exposure levels under the existing conditions for anyone in publicly accessible areas nearby, together with the operation of the other carrier at the site, were well below the federal standard. Prevailing Exposure Standards The U.S. Congress requires that the Federal Communications Commission (“FCC”) evaluate its actions for possible significant impact on the environment. A summary of the FCC’s exposure limits is shown in Figure 1. These limits apply for continuous exposures and are intended to provide a prudent margin of safety for all persons, regardless of age, gender, size, or health. The most restrictive FCC limit for exposures of unlimited duration to radio frequency energy for several wireless services are as follows: Transmit “Uncontrolled” Occupational Limit Wireless Service Band Frequency Public Limit (5 times Public) Microwave (point-to-point) 1–80 GHz 1.0 mW/cm2 5.0 mW/cm2 Millimeter-wave 24–47 1.0 5.0 Part 15 (WiFi & other unlicensed) 2–6 1.0 5.0 CBRS (Citizens Broadband Radio) 3,550 MHz 1.0 5.0 BRS (Broadband Radio) 2,490 1.0 5.0 WCS (Wireless Communication) 2,305 1.0 5.0 AWS (Advanced Wireless) 2,110 1.0 5.0 PCS (Personal Communication) 1,930 1.0 5.0 Cellular 869 0.58 2.9 SMR (Specialized Mobile Radio) 854 0.57 2.85 700 MHz 716 0.48 2.4 600 MHz 617 0.41 2.05 [most restrictive frequency range] 30–300 0.20 1.0 AT&T Mobility • Base Station No. CCL00427 10655 Mary Avenue • Cupertino, California FA No. 10095955, USID No. 13272 X4LL Page 2 of 3 ©2021 General Facility Requirements Antennas for base station use are designed to concentrate their energy toward the horizon, with very little energy wasted toward the sky or the ground. Since the antennas need an unobstructed area in front of them, it is generally not possible for exposure conditions to approach the FCC limits without being physically very near the antennas. Site Description The site at 10655 Mary Avenue in Cupertino was visited by Mr. Scott Walthard, a qualified field technician employed by Hammett & Edison, Inc., during normal business hours on November 12, 2020, a non-holiday weekday. AT&T had installed nine directional panel antennas on a tall pole* within a locked, fenced enclosure in the self-storage facility located at that address. Access to the antennas was restricted by their mounting location and height. Explanatory signs† had been posted on the fenced enclosure and at the base of the pole. Similar antennas were observed about 20 feet to the north on a PG&E lattice tower for use by Sprint, similar antennas were observed about 650 feet to the northeast on a single pole for use by Verizon, and a similar antenna was observed about 265 feet to the south on a pole for use by T-Mobile. Measurement Results The measurement equipment used was a Wandel & Goltermann Type EMR-300 Radiation Meter with Type 18 Isotropic Electric Field Probe (Serial No. F-0034). The meter and probe were under current calibration by the manufacturer. The maximum observed power density level for a person at ground near the site was 0.0028 mW/cm2, which is 1.4% of the most restrictive public limit. The three- dimensional perimeter of RF levels equal to the public exposure limit did not reach any publicly accessible areas. No Recommended Mitigation Measures It is presumed that AT&T and Sprint, as FCC licensees, take adequate precautions to ensure that their employees or contractors comply with FCC occupational exposure guidelines whenever work is required near the antennas themselves. * Reported at 60 feet overall height. † Signs complied with OET-65 color and symbol recommendations. AT&T Mobility • Base Station No. CCL00427 10655 Mary Avenue • Cupertino, California FA No. 10095955, USID No. 13272 X4LL Page 3 of 3 ©2021 Conclusion Based on the information and analysis above, it is the undersigned’s professional opinion that the AT&T Mobility base station located at 10655 Mary Avenue in Cupertino, California, as installed and operating at the time of the visit, complies with the FCC guidelines limiting public exposure to radio frequency energy and, therefore, does not for this reason cause a significant impact on the environment. Authorship The undersigned author of this statement is a qualified Professional Engineer, holding California Registration Nos. E-13026 and M-20676, which expire on June 30, 2021. This work has been carried out under his direction, and all statements are true and correct of his own knowledge except, where noted, when data has been supplied by others, which data he believes to be correct. _____________________________________ William F. Hammett, P.E. 707/996-5200 January 7, 2021 FCC Radio Frequency Protection Guide FCC Guidelines Figure 1 1000 100 10 1 0.1 0.1 1 10 100 103 104 105 Occupational Exposure Public Exposure PCS CellFM PowerDensity(mW/cm2)The U.S. Congress required (1996 Telecom Act) the Federal Communications Commission (“FCC”) to adopt a nationwide human exposure standard to ensure that its licensees do not, cumulatively, have a significant impact on the environment. The FCC adopted the limits from Report No. 86, “Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields,” published in 1986 by the Congressionally chartered National Council on Radiation Protection and Measurements (“NCRP”). Separate limits apply for occupational and public exposure conditions, with the latter limits generally five times more restrictive. The more recent standard, developed by the Institute of Electrical and Electronics Engineers and approved as American National Standard ANSI/IEEE C95.1-2006, “Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” includes similar limits. These limits apply for continuous exposures from all sources and are intended to provide a prudent margin of safety for all persons, regardless of age, gender, size, or health. As shown in the table and chart below, separate limits apply for occupational and public exposure conditions, with the latter limits (in italics and/or dashed) up to five times more restrictive: Frequency Electromagnetic Fields (f is frequency of emission in MHz) Applicable Range (MHz) Electric Field Strength (V/m) Magnetic Field Strength (A/m) Equivalent Far-Field Power Density (mW/cm2) 0.3 – 1.34 614 614 1.63 1.63 100 100 1.34 – 3.0 614 823.8/ f 1.63 2.19/ f 100 180/ f2 3.0 – 30 1842/ f 823.8/ f 4.89/ f 2.19/ f 900/ f2 180/ f2 30 – 300 61.4 27.5 0.163 0.0729 1.0 0.2 300 – 1,500 3.54 f 1.59 f f /106 f /238 f/300 f/1500 1,500 – 100,000 137 61.4 0.364 0.163 5.0 1.0 Frequency (MHz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©2020