Attachment Radiation Hazard

This document pretains to SES-AMD-20160926-00799 for Amended Filing on a Satellite Earth Station filing.

IBFS_SESAMD2016092600799_1151245

Radiation Hazard Analysis 2.4 Meter - General Dynamics NGSO 40 Pago Pago, American Samoa 96799 Introduction A radiation hazard anaylsis is presented for a 2.4 meter Ka band aperture antenna to be installed in Pago Pago American Samoa at the NOAA Weather Service Office. This Radiation Analysis calculates the non- ionizing radiation levels expected to be emitted from the earth station on a worse cases basis and is performed in accordance with the Federal Communications Commissions Office of Engineering and Technology (OET) Bulletin, No. 65. Requirements OET 65 outlines the maximum permissible exposure limits in two cases for operation in this frequency range. 1. The first case is the maximum level that a person may be exposed to in the general population. The exposure limit is defined as a non-ionizing power level equal to 1 milliwatt per centimeter squared averaged over a thirty minute period. 2. The second case is a controlled environment where the maximum permissible exposure limit must not exceed 5 milliwatts per centimeter squared averaged over any six minute period. Summary The results indicate that no significant hazard will be presented to the general population and will be fully mitigated in the controlled area by the use of procedures that require the removal of transmit power before accessing the area around the main reflector. Analysis This analysis was performed on seven zones. The results of this is shown in Radiation Hazard Zones. The Table labeled Input Values provides the input data used to perform the analysis. The table labeled OET 65 Calculated Values provides the intermediate calculation used to perform the assessment in accordance with OET 65. The Analysis is performed for each of the seven radiation zones as shown in figure 1 – Analysis Zones. These zones are: 1. Point between the feed and the sub-reflector 2. The power at the surface of the antenna 3. The power level between the main reflector and ground 4. The near-field or Fresnel region in which the maxima can be reached before the field starts to diminish with distance 5. The Transition region where power begins to decrease inversely with distance from the antenna 6. The Far Field or Fraunhofer region where power decreases inversely with the square of the distance. This is the point at which the antenna beam is fully collimated 7. The off axis level in the near field. This is defined as the area outside of the main beam removed and at least one antenna diameter removed from the main beam 2. Main Reflector 1.Subreflector 4.Near Field 5. Transition 6. Far Field 3. Main Reflector Ground 7.Off Axis Near Field Figure 1 – Analysis Zones Generated 09/20/2016 Rad Haz Base file Page 1 of 2 O3b Engineering PGR

Radiation Hazard Analysis Operator: SES-GS Location Designation: NOAA Pago Pago FCC ID: County: Am. Samoa SES-GS ID: General Dynamics NGSO 40 Town: Paog Pago STA: Territory/Zip: Am. Samoa 96799 Input Values Value Unit Band Frequency GHz D = Aperture Diameter 2.4 Meters L 1000-2000 d = Subreflector Diameter 0.1 Meters S 2000-4000  =Apperture Efficeny 67% percentage C 4000-8000 FCC Designation Ka Band X 8000-12500 F = Frequency 28709 MHz Ku 12500-18000 P = Transmitter Power Watts: 40 Watts K 18000-25500 p = Number Transmitters: 1 Ka 26500-40000 Rua = closest point to uncontrolled area 20 meters O 40000-50000 Elevation angle at closest point R ua 29 Degrees V 50000-75000 OET 65 Calculated Values Formula Value Unit λ= Wavelength c/F 0.0104 meters P 1= Total Antenna Input Power P*p 35.9 watts 4  A G = Antenna Gain G= 2 348457.8105 linear  Antenna Gain dB 10 log10 G 55.42150203 dBi 2 D A = Area of reflector   4.5216 meters2 22 d a = area of subreflector or feed   2 0.00785 meters2 D 2 137.80 meters Rnf = Near-Field Region Rnf = 4 17 Meters AGL > Rnf < R ff 137.8032 >meters Transition Region 330.72768 <meters 2 0.6 D 330.72768 meters Rff = Far Field Region R ff =  160 Meters AGL Exposure Limits Radiation Analysis Zone Formula Level Value General Public Occupational <1mW/cm2 <5mW/cm2 4 Pt >FCC MPE See >FCC MPE See 1 Power Subreflector a 1829.299 mW/cm2 Note 1 Note 2 4 Pt >FCC MPE See <FCC MPE 2 Antenna Surface 3.176 mW/cm2 A Note 1 Pt 3 Main Reflector Ground A 0.794 mW/cm2 <FCC MPE <FCC MPE 16  Pt Pt 4.256 >FCC MPE See 4 Snf =Near-Field Power Density S nf = pi D 2 =4  A  mW/cm2 Note 1 <FCC MPE S nf R nf >FCC MPE See 5 Max Transition Power Density S t= Rnf 4.256 mW/cm2 <FCC MPE Note 1 Pt G >FCC MPE See 6 Max Far field Power Density S ff = 4 R 2 0.911 mW/cm2 <FCC MPE Note 3 7 Off Access Level Near Field S ua =S nf −20dB 0.04256 mW/cm 2 <FCC MPE <FCC MPE Notes 1. The antenna is installed in a controlled location access is restricted to authorized personnel only. The area is marked with RF Radiation Hazard signage. Area not accessible to the general public. 2. Inside the controlled area, MPE levels exceed the MPE exposure for occupational levels. The levels will be reduced to safe MPE by removing power to the transmitters when work is performed on or around the antenna. This area can only be accessed by qualified personnel. 3. The far field develops 41 meters above ground level at the minimum elevation angle which is not accessable to the general public. Generated 09/20/2016 Rad Haz Base file Page 2 of 2 O3b Engineering PGR

CERTIFICATION The preceding analysis confirms the presence of potentially hazardous power flux densities at the terminals which will require physical and operation protections to manage General Population and Occupational Exposure. As appropriate, SES GS will use fencing, signage, and other measures to limit access to the relevant area. Procedures will be in place requiring that transmit power be turned off before work on the 2.4m antennas is performed. Where an enclosed area is necessary, the size of the enclosed area will consider the RF hazards and the surrounding terrain. The signage will clearly state the standard Radiation Hazard warning. Personnel with access to the antenna will be trained to ensure that the antennas are off before working in the vicinity or on the antenna systems directly. I hereby certify I have reviewed the engineering information submitted, and that it is complete and accurate to the best of my knowledge. /s/ Gene McLeod Gene McLeod Program Manager SES Government Solutions September 23, 2016


Document Created: 2016-09-23 16:49:21
Document Modified: 2016-09-23 16:49:21
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