Attachment Exhibit B

This document pretains to SES-MOD-20110131-00073 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2011013100073_865268

Comtech Mobile Datacom Corporation Exhibit B, Page 1 CONUS (EJ90029) Modification Application Radiation Hazard Study — Item 28 Comtech Mobile Datacom Corporation Mobile Earth Station Terminal December, 2010 Introduction Comtech Mobile Datacom Corporation ("CMDC") designs, manufactures, and is licensed to operate Mobile Earth Station Terminals ("MESs") in spectrum allocated to the Mobile Satellite Service under the Federal Communications Commission guidelines of Part 25, Title 47 of the Code of Federal Regulations. This Radiation Hazard Study demonstrates that CMDC‘s MESs meet FCC guidelines for RF exposure. Background Completion of a routine environmental analysis for RF exposure (as described in Federal Communications Commission Office of Engineering and Technology Bulletin 65 ("Bulletin 65"¢)) due to emissions from the MES is one of the requirements to modify the existing blanket license. Bulletin 65 identifies two parameters relating to equipment type and usage that determine the appropriate testing methods and limits. First, devices may be classified as either Mobile or Portable. A Mobile device is intended for use in other than fixed locations and should be separated from the user or bystanders by at least 20 centimeters. Portable devices are intended to be operated within 20 centimeters of the user or bystander. Second, the exposure must be deemed Occupational/Controlled Exposure or General Population/Uncontrolled Exposure. Occupational/Controlled Exposure applies where persons are exposed due to their employment or when they have been made aware of the potential for exposure and are able to exercise control over their exposure. Cases where the general public is exposed or where workers are not fully aware of the potential for exposure or are unable to exercise control over the amount of their exposure fall into the General Population/Uncontrolled Exposure category. CMDC MESs fit into the Mobile and General Population/Uncontrolled Exposure categories. As such, the permissible radiation level may be determined using either Maximum Permissible Exposure or Specific Absorption Rate techniques. CMDC elects to use a Maximum Permissible Exposure analysis using the limits for General Population/Uncontrolled Exposure for frequencies above 1500 MHz shown in section B of the table below.

Comtech Mobile Datacom Corporation Exhibit B, Page 2 CONUS (EJ90029) Modification Application FCCLROHIS FOR AXDAUNMEPESARMBLE EXECSURE (MFE) {A) Timitts for OrecopationalControliedExposure Fregpiency Elecns Fielst Mamebc Fied—— FowerDear Avenigaeg Tune Smeugth {E) (§3 i2E "ad § CVA ~ {untfes)— 4.8§—f & .103 6 an n« 6 —— —~ & (B) Liniits for Ceneral PopulatonUncontrolied Exposure Frequency Hlectac Fielg Magnetic Field Power Density {ninotfes) Aad bao fad Td Kpp & > <In n {= freqguencyinMHz "Plme—waveequivilect power dernity Analysis Method A Maximum Permissible Exposure analysis will be done using the methods described in Bulletin 65 and the source—based time—averaging methods described in Title 47 of the Code of Federal Regulations Part 2.1091. The source—based averaging allows scaling of the exposure level based on the inherent duty cycle of the MES. CMDC‘s MESs are limited to a maximum transmission duty cycle of 52% (a 1.552 second transmission burst every 3.0 seconds). Bulletin 65 offers several methods for calculating the RF Power Density. Three of these methods seem appropriate for this analysis. First, the equations below will predict the power density in the antenna far field and will overstate the density in the near field.

Comtech Mobile Datacom Corporation Exhibit B, Page 3 CONUS (EJ90029) Modification Application dr. ane xz {4) ERP= eipresient (or effective} asofmoy _' hatedspower f 0 F13 p3 ri 4 + Second, the power density may be determined for an antenna close to a ground plane. The following equation provides this result based on 100% reflection from the ground plane. The power density determined by this method will be four times that of the density determined in the far field. Third, the Environmental Protection Agency has recommended a more realistic approximation of those results in a power density increase of 2.56 above the far field case. §« ie This method seems most representative of the typical operating conditions for CMDC‘s MESs and is the method adopted for this analysis.

Comtech Mobile Datacom Corporation Exhibit B, Page 4 CONUS (EJ90029) Modification Application Analysis The separation distance required to produce an RF power density less than one milliwatt per square centimeter will be calculated for all possible antennas. The calculations will be done for the maximum antenna input power of 6 dBW and for a maximum duty cycle of 52 %. The antennas that are available for use are characterized in the table below. Antenna Type Antenna Size Antenna ID yP (meters) Gain (dBi) 1—2010/INT Quadrafilar Helix 0.15 2.9 2—2010/EXT Quadrafilar Helix 0.15 4.8 2—2011/EXT Quadrafilar Helix 0.15 4.8 3—2010/EXT Patch 0.06 4.0 4—2010/INT Quadrafilar Helix 0.15 5.0 5—202/EXT Quadrafilar Helix 0.27 3.9 5—203/EXT Quadrafilar Helix 0.27 3.9 5—2011/EXT Quadrafilar Helix 0.27 3.9 5—2012/EXT Quadrafilar Helix 0.27 3.9 6—2011/INT Patch 0.18 3.7 6—2012/INT Patch 0.18 3.7 6—203/INT Patch 0.18 3.7 7—2011/INT Patch 0.18 6 7—2012/1INT Patch 0.18 6 8—203/EXT Patch 0.19 3.7 9—ASDR/INT Quadrafilar Array Helix 0.315 11 10—ASDO/INT Patch 0.047 2.5 11—C50/INT Circular Patch 0.1524 4.5

Comtech Mobile Datacom Corporation Exhibit B, Page 5 CONUS (EJ90029) Modification Application Using the maximum power into the antenna of 6 dBW, a duty cycle of 52% and the antenna gains from the table above; the minimum separations to achieve one milliwatt per square centimeter power densities are calculated and listed in Table B below. Separation distance for 1 mW Antenna . ID Type per square ceptlmeter Power Density (cm) 1—2010/INT Quadrafilar Helix 29 2—2010/EXT Quadrafilar Helix 36 2—2011/EXT Quadrafilar Helix 36 3—2010/EXT Patch 33 4—2010/INT Quadrafilar Helix 37 5—202/EXT Quadrafilar Helix 32 5—203/EXT Quadrafilar Helix 32 5—2011/EXT Quadrafilar Helix 32 5—2012/EXT Quadrafilar Helix 32 6—2011/INT Patch 31 6—2012/INT Patch 31 6—203/INT Patch 31 7—2011/INT Patch 41 7—2012/1NT Patch 41 8—203/EXT Patch 31 9— Quadrafilar Helix 5g ASDR/INT Array 10— ASDO/INT Patch 28 11—C50/INT Circular Patch 41 The typical CMDC MES is installed on the top surface of a land vehicle, ship, or aircraft. Distances to operating personnel and the general population will be greater than the separation distances calculated above. The table below indicates the typical CMDC MES mounting location for various applications and the minimum distance necessary to prevent a hazard to operators and the general population.

Comtech Mobile Datacom Corporation Exhibit B, Page 6 CONUS (EJ90029) Modification Application Typical minimum Minimum distance necessary Minimum distance necessary Application installation to prevent hazard (cm) for to prevent hazard (cm) for separation from 9—ASDR/INT 10—ASDO/INT people (cm) Trucking 90 58 28 Rail 300 58 28 Container 200 58 28 Boats >300 58 28 Aviation 75 58 28 . hss . . Minimum distance necessary Application Typical minimum installation to prevent hazard (cm) for all separation from people (cm) other antennas Trucking 90 41 Rail 300 41 Container 200 41 Boats >300 41 Aviation 75 41 Conclusion The preceding analysis shows that the CMDC MESs meet the Federal Communications Commission guidelines for RF exposure.


Document Created: 2019-04-21 05:01:10
Document Modified: 2019-04-21 05:01:10
© 2024 FCC.report
This site is not affiliated with or endorsed by the FCC