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HomeMy WebLinkAboutAttachment 12-Calculated Radio Frequency Exposure Report C Squared Systems, LLC 65 Dartmouth Drive Auburn, NH 03032 (603) 644-2800 support@csquaredsystems.com Calculated Radio Frequency Exposure Report Barnstable CC 831740 36 Wequaquet Lane, Barnstable, MA 02632 December 29, 2021 i Table of Contents 1. Introduction ..................................................................................................................................................................................... 1 2. FCC Guidelines for Evaluating RF Radiation Exposure Limits ......................................................................................... 2 3. Power Density Calculation Methods ......................................................................................................................................... 3 4. Antenna Configuration for % MPE Calculations ................................................................................................................... 4 5. Calculated % MPE Results .......................................................................................................................................................... 5 6. Measurement Procedure ............................................................................................................................................................... 7 7. Measured % MPE Results ........................................................................................................................................................... 8 8. Conclusion ..................................................................................................................................................................................... 10 9. Statement of Certification .......................................................................................................................................................... 10 Attachment A: References ............................................................................................................................................................... 11 Attachment B: FCC Limits for Maximum Permissible Exposure (MPE) ............................................................................ 12 Attachment C: Antenna Model Data Sheets and Electrical Patterns ...................................................................................... 14 Attachment D: Calibration Certificates ........................................................................................................................................ 16 List of Figures Figure 1: Aerial View of Proposed Site Location ......................................................................................................... 1 Figure 2: Graph of Percent of MPE vs. Distance.......................................................................................................... 5 Figure 3: Aerial View of Measurement Points (Imagery Date 10/23/2021, courtesy Google Earth ©2021) ............... 9 Figure 4: Graph of FCC Limits for Maximum Permissible Exposure (MPE) ............................................................ 13 Figure 5: EA-5091 Probe Calibration ......................................................................................................................... 16 Figure 6: NBM-550 Meter Calibration ....................................................................................................................... 17 List of Tables Table 1: Survey Information ......................................................................................................................................... 1 Table 2: Antenna Inventory .......................................................................................................................................... 4 Table 3: Maximum Percent of Exposure Values ........................................................................................................ 6 Table 4: Instrumentation Information ........................................................................................................................... 7 Table 5: Measured % MPE Results ............................................................................................................................. 8 Table 6: FCC Limits for Maximum Permissible Exposure ........................................................................................ 12 Barnstable CC 831740 1 December 29, 2021 1. Introduction The purpose of this report is to investigate compliance with applicable FCC regulations for the proposed monopole tower at 36 Wequaquet Lane in Barnstable, MA. The coordinates of the tower are 41° 39' 37.18" N, 70° 19' 35.43" W. The Proposed Site is intended to replace a nearby tower and its equipment located at 1047 Falmouth Road (Existing Site). This report considers general equipment configurations typically deployed by commercial wireless service providers to calculate the cumulative % MPE (Maximum Permissible Exposure) for the proposed facility, which is designed to accommodate up to four antenna arrays. The arrays would be arranged vertically with approximately 10’ separation (center-to-center) as per industry convention, ranging from 107’ AGL (above ground level) to 77’ AGL as shown in the site plans 1. Additionally, field measurements of the ambient % MPE in the area were recorded, which include the % MPE contribution from the Existing Site to be replaced by the Proposed Site. Figure 1: Aerial View of Proposed Site Location Site Address 36 Wequaquet Lane, Barnstable, MA Name of Individual Conducting Survey Martin Lavin Date and Time of Survey 12/17/2021; 09:15 AM – 11:45 AM Table 1: Survey Information 1 Advanced Engineering Group, Site Plans dated November 11, 2021 (Rev. 4). Barnstable CC 831740 2 December 29, 2021 2. FCC Guidelines for Evaluating RF Radiation Exposure Limits In 1985, the FCC established rules to regulate radio frequency (RF) exposure from FCC licensed antenna facilities. In 1996, the FCC updated these rules, which were further amended in August 1997 by OET Bulletin 65 Edition 97-01. These new rules include Maximum Permissible Exposure (MPE) limits for transmitters operating between 300 kHz and 100 GHz. The FCC MPE limits are based upon those recommended by the National Council on Radiation Protection and Measurements (NCRP), developed by the Institute of Electrical and Electronics Engineers, Inc., (IEEE) and adopted by the American National Standards Institute (ANSI). The FCC general population/uncontrolled limits set the maximum exposure to which most people may be subjected. General population/uncontrolled exposures apply in situations in which the general public may be exposed, or in which persons that are exposed as a consequence of their employment may not be fully aware of the potential for exposure or cannot exercise control over their exposure. Public exposure to radio frequencies is regulated and enforced in units of milliwatts per square centimeter (mW/cm2). The general population exposure limits for the various frequency ranges are defined in the attached “FCC Limits for Maximum Permissible Exposure (MPE)” in Attachment B of this report. Higher exposure limits are permitted under the occupational/controlled exposure category, but only for persons who are exposed as a consequence of their employment and who have been made fully aware of the potential for exposure, and they must be able to exercise control over their exposure. General population/uncontrolled limits are five times more stringent than the levels that are acceptable for occupational, or radio frequency trained individuals. Attachment B contains excerpts from OET Bulletin 65 and defines the Maximum Exposure Limit. Finally, it should be noted that the MPE limits adopted by the FCC for both general population/uncontrolled exposure and for occupational/controlled exposure incorporate a substantial margin of safety and have been established to be well below levels generally accepted as having the potential to cause adverse health effects. Barnstable CC 831740 3 December 29, 2021 3. Power Density Calculation Methods The calculated ground-level power density results displayed in the following figures were generated using the following formula as outlined in FCC bulletin OET 65: Power Density =�EIRP𝜋𝜋 × 𝑅𝑅2� X Off Beam Loss Where: EIRP = Effective Isotropic Radiated Power R = Radial Distance = �(𝐻𝐻2 +𝑉𝑉2 ) H = Horizontal Distance from antenna V = Vertical Distance from center of antenna Off Beam Loss is determined by the selected antenna patterns Ground reflection factor of 2.0 These calculations assume that the antennas are operating at full power and 100 percent capacity, and that all antenna channels are transmitting simultaneously. Obstructions (trees, buildings, etc.) that would normally attenuate the signal are not taken into account. The calculations also assume even terrain in the area of study and do not take consider terrain elevations which could further attenuate the signal. As a result, the calculated power density and corresponding % MPE levels reported below are much higher than the actual signal levels will be from the final antenna configuration. The percent of MPE values presented in this report reflect levels that one may encounter from one sector of a carrier’s antennas. Most carriers use multiple sectors per site with azimuths approximately 90-120 degrees apart; therefore, one could not be standing in the main beam of any two different sectors at the same time. In cases where antenna models and downtilts are not uniform across all sectors, the antenna model with the highest gain and downtilt was used for the calculations. This results in a conservative or “worst case” assumption for percent of MPE calculations. Barnstable CC 831740 4 December 29, 2021 4. Antenna Configuration for % MPE Calculations Table 2 below outlines the general antenna configurations considered in this analysis. To account for the cumulative % MPE for up to four operators, the same configuration was assumed with the industry standard 10-feet vertical separation between each operator’s antenna arrays. The associated data sheets and antenna patterns for these specific antenna models are included in Attachment C. Table 2: Antenna Inventory2 . 2 Transmit power assumes 0 dB of cable loss. Power at Antenna (Watts) 750 160 14.9 4944 65 880 160 15 5060 60 1900 160 17.9 9866 69 2100 240 18.4 16604 64 750 160 14.9 4944 65 880 160 15 5060 60 1900 160 17.9 9866 69 2100 240 18.4 16604 64 750 160 14.9 4944 65 880 160 15 5060 60 1900 160 17.9 9866 69 2100 240 18.4 16604 64 750 160 14.9 4944 65 880 160 15 5060 60 1900 160 17.9 9866 69 2100 240 18.4 16604 64 3rd-Tenant NHH-65B-R2B 0 6 87 4th-Tenant NHH-65B-R2B 0 6 77 NHH-65B-R2B 0 6 107 2nd-Tenant NHH-65B-R2B 0 6 97 Mech. Downtilt Length (ft) Antenna Centerline Height (ft) 1st-Tenant Operator TX Freq (MHz) Ant Gain (dBi) Power EIRP (Watts)Antenna Model Beam Width Barnstable CC 831740 5 December 29, 2021 . alculated %esults The calculated % MPE results for the antenna configuration listed above are shown in Figure 2 below. Each frequency band is calculated as well as the resulting cumulative percent of MPE. For completeness, the calculations for this analysis range from 0 feet horizontal distance (directly below the antennas) to a value of 3,000 feet horizontal distance from the antennas. In addition to the other worst-case scenario considerations that were previously mentioned, the % MPE calculations to each horizontal distance point away from the antennas were completed using a local maximum off beam antenna gain (within ± 5 degrees of the true mathematical angle) to incorporate a realistic worst-case scenario. Figure 2: Graph of Percent of MPE vs. Distance The highest percent of MPE (19.68%), reflecting the combined total of four typical tenant configurations (see Table 3 below), is calculated to occur at a horizontal distance of 468 feet from the antennas. Please note that the percent of MPE calculations close to the site take into account off beam loss, which is determined from the vertical pattern of the antennas used. Therefore, RF power density levels may increase as the distance from the site increases. At distances of approximately 700 feet and beyond, one would now be in the main beam of most antenna patterns and off beam loss is no longer considered. Beyond this point, RF levels become calculated solely on distance from the site, and the percent of MPE decreases significantly as distance from the site increases. Barnstable CC 831740 6 December 29, 2021 Table 3 below lists the calculated percent of MPE values as well as the associated parameters that were included in the calculations. As stated in Section 3, all calculations assume that the antennas are operating at full power and 100 percent capacity, and that all antenna channels are transmitting simultaneously. Obstructions (trees, buildings, etc.) that would normally attenuate the signal are not taken into account. Additionally, a six-foot height offset was considered in this analysis to account for average human height standing at ground level. As a result, the calculated % MPE levels are significantly higher than the actual levels will be from the final installation. The results presented in Figure 2 and Table 3 assume level ground elevation from the base of the tower out to the horizontal distances calculated. Table 3: Maximum Percent of Exposure Values 4 5 6 4 Transmit power assumes 0 dB of cable loss. 5 Frequencies listed are representative of the operating bands of typical commercial wireless operators. 6 The total % MPE listed is a summation of each unrounded contribution. Therefore, summing each rounded value may not reflect the total value listed in the table. Operator Frequency Band Number of Trans. Power out of Base Station Per Transmitter (Watts) Antenna Height (Feet) Distance to the Base of Antennas (Feet) Power Density (mW/cm2) Limit (mW/cm2)% MPE Composite % MPE 1900 MHz 1 160.0 468 0.004064 1.000 0.41% 2100 MHz 1 240.0 468 0.005990 1.000 0.60% 750 MHz 1 160.0 468 0.006220 0.500 1.24% 850 MHz 1 160.0 468 0.005517 0.567 0.97% 1900 MHz 1 160.0 468 0.008823 1.000 0.88% 2100 MHz 1 240.0 468 0.014820 1.000 1.48% 750 MHz 1 160.0 468 0.006732 0.500 1.35% 850 MHz 1 160.0 468 0.006454 0.567 1.14% 1900 MHz 1 160.0 468 0.012913 1.000 1.29% 2100 MHz 1 240.0 468 0.023021 1.000 2.30% 750 MHz 1 160.0 468 0.006928 0.500 1.39% 850 MHz 1 160.0 468 0.007044 0.567 1.24% 1900 MHz 1 160.0 468 0.000607 1.000 0.06% 2100 MHz 1 240.0 468 0.026464 1.000 2.65% 750 MHz 1 160.0 468 0.006975 0.500 1.40% 850 MHz 1 160.0 468 0.007271 0.567 1.28% Total 19.68% 1st Tenant 2nd Tenant 3rd Tenant 4th Tenant 107.0 97.0 87.0 77.0 3.22% 4.85% 6.22% 5.39% Barnstable CC 831740 7 December 29, 2021 6. Measurement Procedure Frequencies from 300 KHz to 50 GHz were measured using the Narda Probe EA 5091, E-Field, shaped, FCC probe in conjunction with the NBM550 survey meter. The EA 5091 probe is “shaped” such that in a mixed signal environment (i.e.: more than one frequency band is used in a particular location), it accurately measures the percent of MPE. From FCC OET Bulletin No. 65 - Edition 97-01 – “A useful characteristic of broadband probes used in multiple-frequency RF environments is a frequency-dependent response that corresponds to the variation in MPE limits with frequency. Broadband probes having such a "shaped" response permit direct assessment of compliance at sites where RF fields result from antennas transmitting over a wide range of frequencies. Such probes can express the composite RF field as a percentage of the applicable MPEs”. Probe Description - As suggested in FCC OET Bulletin No. 65 - Edition 97-01, the response of the measurement instrument should be essentially isotropic, (i.e., independent of orientation or rotation angle of the probe). For this reason, the Narda EA 5091 probe was used for these measurements. Sampling Description - At each measurement location, a spatially averaged measurement is collected over the height of an average human body. The NBM550 survey meter performs a time average measurement while the user slowly moves the probe over a distance range of 20 cm to 200 cm (about 6 feet) above ground level. The results recorded at each measurement location include average values over the spatial distance. Instrumentation Information - A summary of specifications for the equipment used is provided in the table below. Manufacturer Probe Calibration Date Calibration Interval Meter Calibration Date Calibration Interval Frequency Range Field Measured Standard Measurement Range 300 KHz-50 GHz Electric Field U.S. FCC 1997 Occupational/Controlled 0.5 – 600 % of Standard 24 Months Probe Specifications Narda Microwave EA 5091, Serial# 01135 January 2021 24 Months NBM550, Serial# B-1149 January 2021 Table 4: Instrumentation Information Instrument Measurement Uncertainty - The total measurement uncertainty of the NARDA measurement probe and meter is no greater than ±2 dB. The factors which contribute to this include the probe’s frequency response deviation, calibration uncertainty, ellipse ratio, and isotropic response7. Every effort is taken to reduce the overall uncertainty during measurement collection including pointing the probe directly at the likely highest source of emissions 7 For further details, please refer to Narda Safety Test Solutions NBM550 Probe Specifications. https://www.narda-sts.com/en/wideband-emf/nbm-550/eID/pd/pdce/25973/pdfr/11005/ Barnstable CC 831740 8 December 29, 2021 7. Measured % MPE Results The measured % MPE results at ground level around the Existing Site and Proposed Site are presented below in Table 5 and Figure 3. Table 5 details the field survey locations along with the corresponding measured % MPE value at each specific point. The highest % MPE measured was 6.425% (Uncontrolled/General Population MPE) and was recorded on Canterbury Circle, near Old Strawberry Hill Road (location 10), approximately 879 feet southeast of the Existing Site. All % MPE values area in reference to the FCC General Population/Uncontrolled exposure limit. Table 5: Measured % MPE Results 8 8 Measurements are broadband and would consist of % MPE contribution of the Existing Site along with any other RF sources operating in the frequency bands measured by the instrument. 1 Rear parking lot of Proposed Site property 41.6600 -70.3261 430 1.055% 2 Strawberry Hill Medical Bldg.41.6603 -70.3252 535 2.277% 3 Front parking lot of Proposed Site property 41.6596 -70.3260 267 3.155% 4 CVS, east parking lot 41.6597 -70.3267 404 2.637% 5 St. George Greek Orthodox Church 41.6596 -70.3283 758 3.762% 6 Harbor Church 41.6593 -70.3220 1029 5.430% 7 Blueberry Hill Rd, btw Strawberry Hill Rd and Blackberry Ln.41.6576 -70.3264 515 2.590% 8 Blueberry Hill Rd at Blackberry Ln.41.6580 -70.3252 373 1.759% 9 Blueberry Hill Rd, near Old Strawberry Hill Rd.41.6579 -70.3238 636 6.135% 10 Canterbury Circle, near Old Strawberry Hill Rd.41.6570 -70.3237 879 6.425% 11 Centerville Food Mart parking lot 41.6584 -70.3294 1014 3.006% Location Description Latitude Longitude Dist. From Existing Site (feet) Measured % MPE (Uncontrolled / General Population) Barnstable CC 831740 9 December 29, 2021 Figure 3 below is an aerial view 9 of the Existing and Proposed Site locations and the surrounding area, along with the measurement locations listed in Table 5. Figure 3: Aerial View of Measurement Points (Imagery Date 10/23/2021, courtesy Google Earth ©2021) 9 Google Earth, https://earth.google.com/web/ Barnstable CC 831740 10 December 29, 2021 8. Conclusion The above analysis concludes that RF exposure at ground level from the Proposed Site will be below the maximum permissible levels as outlined by the FCC in OET Bulletin 65 Ed. 97-01. Using the conservative calculation methods and parameters detailed above, the maximum cumulative percent of MPE of four typical equipment configurations is calculated to be 19.68% of the FCC limit (General Population/Uncontrolled). This maximum percent of MPE value is calculated to occur 468 feet away from the Proposed Site. The maximum measured percent of MPE of the selected points in the area around the Existing Site is 6.425% of the FCC limit (General Population/Uncontrolled). This maximum measured % MPE value occurred on Canterbury Circle, near Old Strawberry Hill Road (location 10), approximately 879 feet southeast of the Existing Site 9. Statement of Certification I certify to the best of my knowledge that the statements in this report are true and accurate. The calculations follow guidelines set forth in FCC OET Bulletin 65 Edition 97-01, IEEE Std. C95.1, and IEEE Std. C95.3. ____________________________ December 29, 2021 Report Prepared By: Keith Vellante Director – RF Services C Squared Systems, LLC Date Barnstable CC 831740 11 December 29, 2021 Attachment A: References OET Bulletin 65 - Edition 97-01 - August 1997 Federal Communications Commission Office of Engineering & Technology IEEE C95.1-2005, IEEE Standard Safety Levels With Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz IEEE-SA Standards Board IEEE Std C95.3-2002 (R2008), IEEE Recommended Practice for Measurements and Computations of Radio Frequency Electromagnetic Fields With Respect to Human Expsoure to Such Fields, 100 kHz-300 GHz IEEE-SA Standards Board Barnstable CC 831740 12 December 29, 2021 Attachment B: FCC Limits for Maximum Permissible Exposure (MPE) (A) Limits for Occupational/Controlled Exposure 10 Frequency Range (MHz) Electric Field Strength (E) (V/m) Magnetic Field Strength (E) (A/m) Power Density (S) (mW/cm2) Averaging Time |E|2, |H|2 or S (minutes) 0.3-3.0 614 1.63 (100)* 6 3.0-30 1842/f 4.89/f (900/f2)* 6 30-300 61.4 0.163 1.0 6 300-1500 - - f/300 6 1500-100,000 - - 5 6 (B) Limits for General Population/Uncontrolled Exposure 11 Frequency Range (MHz) Electric Field Strength (E) (V/m) Magnetic Field Strength (E) (A/m) Power Density (S) (mW/cm2) Averaging Time |E|2, |H|2 or S (minutes) 0.3-1.34 614 1.63 (100)* 30 1.34-30 824/f 2.19/f (180/f2)* 30 30-300 27.5 0.073 0.2 30 300-1500 - - f/1500 30 1500-100,000 - - 1.0 30 f = frequency in MHz * Plane-wave equivalent power density Table 6: FCC Limits for Maximum Permissible Exposure 10 Occupational/controlled limits apply in situations in which persons are exposed as a consequence of their employment provided those persons are fully aware of the potential for exposure and can exercise control over their exposure. Limits for occupational/controlled exposure also apply in situations when an individual is transient through a location where occupational/controlled limits apply provided he or she is made aware of the potential for exposure. 11 General population/uncontrolled exposures apply in situations in which the general public may be exposed, or in which persons that are exposed as a consequence of their employment may not be fully aware of the potential for exposure or cannot exercise control over their exposure. Barnstable CC 831740 13 December 29, 2021 Plane-wave Equivalent Power Density Frequency (MHz) Figure 4: Graph of FCC Limits for Maximum Permissible Exposure (MPE) 1.34 100,000 1,500 Barnstable CC 831740 14 December 29, 2021 Attachment C: Antenna Model Data Sheets and Electrical Patterns 750 MHz Manufacturer: Commscope Model #: NHH-65B-R2B-4 Frequency Band: 698-806 MHz Gain: 14.5 dBi Vertical Beamwidth: 12.4° Horizontal Beamwidth: 65° Polarization: ±45° Dimensions (L x W x D): 72” x 11.9” x 7.1” 880 MHz Manufacturer: Commscope Model #: NHH-65B-R2B-4 Frequency Band: 806-896 MHz Gain: 14.7 dBi Vertical Beamwidth: 11.2° Horizontal Beamwidth: 60° Polarization: ±45° Dimensions (L x W x D): 72” x 11.9” x 7.1” 1900 MHz Manufacturer: Commscope Model #: NHH-65B-R2B-4 Frequency Band: 1850-1990 MHz Gain: 17.7 dBi Vertical Beamwidth: 5.2° Horizontal Beamwidth: 69° Polarization: ±45° Dimensions (L x W x D): 72” x 11.9” x 7.1” Barnstable CC 831740 15 December 29, 2021 2100 MHz Manufacturer: Commscope Model #: NHH-65B-R2B-4 Frequency Band: 1920-2200 MHz Gain: 18.6 dBi Vertical Beamwidth: 4.9° Horizontal Beamwidth: 64° Polarization: ±45° Dimensions (L x W x D): 72” x 11.9” x 7.1” Barnstable CC 831740 16 December 29, 2021 Attachment D: Calibration Certificates Figure 5: EA-5091 Probe Calibration Barnstable CC 831740 17 December 29, 2021 Figure 6: NBM-550 Meter Calibration