Attachment C36 Hazard Study

This document pretains to SES-LIC-20150422-00254 for License on a Satellite Earth Station filing.

IBFS_SESLIC2015042200254_1085775

RF Radiation Hazard Analysis PSSI C36 Antenna Diameter (D) = 3.7 meters, 370 cm Antenna Surface Area (SA) = 107521 sq cm Sub-reflector Diameter (DS) = 60.96 cm Sub-reflector Surface Area (AS) = 2917.155 sq cm C-Band Wavelength at 6.175 GHz Center Band, LAMBDA = .049 meters, 4.90 cm Power at output at HPA = 400 watts Path Loss to OMT (IL) = 2.25 dB Power at OMT Flange (P) = 238.23 watts Antenna Gain at 6.1750 GHz (G) = 44.0 dBi Antenna Gain given in Power Ratio (GES) = 2.5118+4 Antenna Aperture Efficiency (N) = .627 or 62.7% Region Radiation Level Hazard Assessment Far Field (RF) = 25,910 cm, 259.10 meters 1.588 mW/cm² Potential Hazard Near Field (RN) = 10,795 cm, 107.95 meters 3.595 mW/cm² Potential Hazard Transition Region (RT) ≤ 3.595 mW/cm² Potential Hazard Sub-Reflector Region (WS) 163.33 mW/cm² Potential Hazard Main Reflector Region (WM) 2.8684 mW/cm² Potential Hazard Power Density between Reflector and Ground 1.4342 mW/cm² Potential Hazard Power Density between Reflector Edge and Ground 0.00312 mW/cm² Satisfies ANSI Conclusion: Based on the above analysis, harmful areas of radiation do exist in areas around the antenna and in the path of the antenna toward the satellite that it is pointed. The area occupied by the general public, “uncontrolled environment”, will not exceed the ANSI limit of 1mW/cm² because precautions will be taken to warn, educate and limit the access of personnel around the areas of the antenna and its path that may pose a radiation hazard. The bottom edge of the antenna is 8 feet high when deployed which moves the hazard away from the public. Normal look angles for domestic operation move the potential hazard even further away from the general public. As well during operation no maintenance, operation or public will be able to have access to the area around the sub-reflector region. This area has the greatest concentration of radiation, but fortunately is not accessible during operation due to the operational angle of the antenna and the height above ground level. In addition the antenna will be marked with the standard radiation hazard signs. The warning signs will warn personnel to avoid the area around and in front of the reflector when the transmitter is operational. To ensure compliance with safety limits, the Earth Station transmitters will be turned off and marked to remain off whenever maintenance and repair personnel are required to work in the areas of potential hazard as defined in the above study. Additionally, all Earth Station personnel will be trained to insure that the antenna path is clear at all times while the transmitter is in operation. Note: See the following sheet for how the above calculations were made.

Analysis of Non-Ionizing Radiation PSSI C36 – Supporting Calculations Antenna Diameter, (D) = ……………… D = 3.7 m D = 370 cm Antenna Surface Area, (Sa) =…………. Sa =   (D  D/4) Sa = 10.7521 sq m Sa = 107521.00 cm² Sub Reflector Diameter, (Ds) =……….. Ds = .6096 m Ds = 60.96 cm Sub Reflector Area, (As) =……………. As =   (Ds  Ds/4) As = .2917155 m² As = 2917.155 cm² Center Frequency, (Cf) =……………… Cf = 6.175 GHz Wavelength at (Cf), (λ) =………. λ = .049 meters λ = 4.9 cm Transmit Power at HPA Flange, (P1) =... P1 = 400 Watts P2 = log (P1)10 P2 = 26.02 dBw Path Loss from HPA to OMT, (Loss) =... Loss = .25 dB HPA Back off from Saturation, (Loss2) =. Loss 2 = 2.0 dB Power at OMT, (P) =…… P3 = P2-Loss-Loss2 P3 = 23.77 dBw (OMT power in dBw) P = 10 P3/10 P = 238.23 Watts (OMT in Watts) Antenna Gain at (Cf), (Gain) =………… Gain = 44.0 dBi Antenna Gain/ Power Ratio, (Ges) =…... Ges = 10Gain/10 Ges = 2.5118-104 Ratio Antenna Aperture Efficiency, (n) =……. n = .627 or n = 62.7% Far Field (Rf) = Rf = (0.6  (D  D))/ λ Rf = 259.10 meters Rf = 25,910 cm Far Field Pwr Density (Wf) = Wf = (Ges  P)/(4  )  (Rf  Rf) Wf = 0.001588 W/cm² Wf = 1.588 mW/cm² Near Field (Rn) = Rn = (D  D)/4  λ Rn = 10,795 cm Near Field Pwr Density (Wn) = Wn = ((16  n  P)/   (D  D)) Wn = 0.003595 W/cm² Wn = 3.595 mW/cm² Transition Region (Rt) = Rt = Wn  1 Rt ≤ 3.595 mW/cm² Pwr Density at Sub Reflector (Ws) = Ws = (2  P)/ As Ws = .1633 W/cm² Ws = 163.33 mW/cm² Main Reflector Region Pwr Density (Wm) = Wm = (2  P)/ Sa Wm = 0.0028684 W/cm² Wm = 2.8684 mW/cm² Pwr Density / Main Reflector and Ground (Wg) = Wg = (P/Sa) Wg = 1.4342 mW/cm² Pwr Density / Reflector Edge and Ground (WI) = WI = Wg/D WI = 0.00312 mW/cm²


Document Created: 2015-04-22 13:13:46
Document Modified: 2015-04-22 13:13:46
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