Attachment Rad haz

This document pretains to SES-STA-20030501-00567 for Special Temporal Authority on a Satellite Earth Station filing.

IBFS_SESSTA2003050100567_316583

ANALYSIS O~~N-IONIZING RADIATION FOR A 2.4 METER EARTH STATION .ANTENNA This reportanalyzesthe non-ionizingradiationlevelsfor a 4.5 meterearth station. The Officeof Engineeringand TechnologyBulletinNo. 65, Edition97-01 (August,1997)specifiesthat the maximumlevel of non-ionizing radiationthat a personmay be exposedto, for Occupational/Controlled environments,over anyone-tenthhour (six minute)periodfor frequenciesabove 1,500MHz is an averagepowerdensityof 5 mW/cm2.The reportwill determinethe powerflux densitiesof the proposedearth stationin the near field, transitionregion,far field, betweenthe feed and reflectorsurface,at the reflectorsurface,and betweenthe edge of the antennaand the ground. The followingparameterswere used to calculatethe variouspowerflux densitiesfor this earth station: Antenna Diameter, (D) = 2.4 meters Antenna surface area, (As) = nOZ/4 = 4.52 m2 Feed FlangeDiameter,(OJ = 15.2 cm Area of Feed Flange, (Fa) = 7tDf2/4 = 181.46 cm2 Wavelengthat 6.175 GHz, (A.) = 0.049 meters Transmit Power at Flange. (P) = 13.5 Watts AntennaGain, (G) = 15,849 AntennaApertureefficiency,(n) . 64 % 1. Near Field Calculation Power flux densityis consideredto be at a maximumvalue within a cylindricalvolumehavingthe samediameter as the antenna and throughout the entire length of the of the defined region. Beyond the near field region, the power density decreases linearly with distance from the antenna reflector. Extent of the near (R",) = D2/4A. = 29.4 meters The maximum power density in the near field is determined by: Near field power density (Sn,) =(16'lP)/n02 = 2.2 mW/cm2 2. Transition Reaion Calculation The transition region is located between the near field and far field regions. The power density in the transition region (5.) decreases inversely with distance. thus the maximum power density in the transition region will not exceed that calculated for the near field region. or 2.2 mW/cm 2. ~"",,-~, tilcW

RADIATION HAZARD STUDY PAGE 2 3. Far Field Calculation The distance to the beginning of the far field region is calculated as follows: Distance to the Far Field Region (Rff) = O.6D2n. = 10.5 meters Far field powerdensity(~) = G*P/41tR.,2 = 0.3 mW/crn2 4. Reaion Between Feed Flange and Reflector Transmitter power from the feed horn is directed toward the antenna reflector surface and is generally confined within a conical shape defined by the feed horn geometry. The power density between the feed and the surface of the antenna reflector is greatest at the feed flange and is calculated as follows: Power Densityat Feed Flange (5,) = 4P I Fa = 2975.9mW/crn2 The power density at the antenna reflector surface is determined in the same manner as the power density at the feed flange, but using the area of the reflector surface rather than the feed flange area. Power Density at the Reflector Surface (Ss) . 4P/A. = 3.4 mW/cm2 6. Recion between the Reflector and the Ground The power density between the antenna reflector and the ground depends on the angle of incidence and the vertical distance from the main beam, but in no event will exceed the power density at the antenna reflector surface, or 3.4 mW/cm2.

RADIATION HAZARD STUDY PAGE 3 SUMMARY OF CALCULATIONS MAXIMUM REGION CALCULATED PERMISSIBLE EXPOSURE 1. Near Field power density (5nf) 2.2 mW/an2 5 mW/cm2 Complies 2. Transition Region power density (St) 2.2 mW/an2 5 mW/cm2 Complies 3. Far Field powerdensity(Str) 0.3 mW/crn2 5 mW/cm2 Complies 4. Between Feed Flange and Reflector 2975.9 mW/cm2 5 mW/cm2 Potential Hazard 5. Reflector Surface (S.) 3.4 mW/cm,.2 5 mW/cm2 Complies 6. Between Antenna Reflector and Ground 3.4 mW/cm2 5 mW/cm2 Complies 7. Conclusions Basedon the above analysis, it is concluded that the radiofrequency emissions from the proposed earth station, except for the power density levels between the feed flange and the antenna reflector surface, will be below the maximum permissible exposure (MPE) limits for Occupational/Controlled environments. The area surrounding the earth station will be controlled and signs posted in order to extablish the environment as "Occupational/Controlled." Further, in order to limit exposure to the MPE limit for the feed flange/antenna reflector region, the transmitter will be turned off during antenna maintenance. 8. Certification I hereby certify that I am the technically qualified person responsible for the preparation of this radiation hazard assessment, that this assessment complies with OET Bulletin No. 65, 97-01, and that it is complete and correct to the best of my knowledge. BY: LY( O.Young Telecommunications Engineer Kellerand HeckmanLLP


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Document Modified: 2019-05-25 19:38:25
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