Attachment Exhibit B

This document pretains to SES-MOD-20170804-00862 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2017080400862_1256437

                                                                                           Exhibit B
                                                                                   Spire Global, Inc.
                                                                             Response to Question 28
                                                                                     FCC Form 312
          Analysis of Non-Ionizing Radiation for a 2.46-Meter Earth Station System

       This report analyzes the non-ionizing radiation levels for a 2.46-meter earth station
system. The analysis and calculations performed in this report comply with the methods
described in the Federal Communications Commission (“FCC”) Office of Engineering and
Technology Bulletin No. 65 (“Bulletin No. 65”), which was first published in 1985 and revised
in 1997 in Edition 97-01. The radiation safety limits used in the analysis are in conformance
with the FCC Report and Order (“R&O”) 96-326. Bulletin No. 65 and the FCC R&O
(collectively “FCC RF Guidelines”) specifies that there are two separate tiers of exposure limits
that are dependent on the situation in which the exposure takes place and/or the status of the
individuals who are subject to the exposure.

        The Maximum Permissible Exposure (“MPE”) limits for persons in a General
Population/Uncontrolled environment are shown in Table 1. The General
Population/Uncontrolled MPE is a function of transmit frequency and is for an exposure period
of thirty minutes or less. The MPE limits for persons in an Occupational/Controlled
environment are shown in Table 2. The Occupational MPE is a function of transmit frequency
and is for an exposure period of six minutes or less. The purpose of the analysis described in
this report is to determine the power flux density levels of the earth station in the far-field, near-
field, transition region, and between the antenna edge and the ground and to compare these
levels to the specified MPEs.
              Table 1. Limits for General Population/Uncontrolled Exposure (MPE)
            Frequency Range (MHz)                         Power Density (mW/cm2)
 30-300                                             0.2
 300-1500                                           Frequency (MHz)*(0.8/1200)
 1500-100,000                                       1.0


                 Table 2. Limits for Occupational/Controlled Exposure (MPE)
            Frequency Range (MHz)                         Power Density (mW/cm2)
 30-300                                             1.0
 300-1500                                           Frequency (MHz)*(4.0/1200)
 1500-100,000                                       5.0


                                                                                       Exhibit B
                                                                               Spire Global, Inc.
                                                                         Response to Question 28
                                                                                 FCC Form 312

        Table 3. Formulas and Parameters Used for Determining Power Flux Densities
    Parameter          Symbol            Formula            Value             Units
     Antenna                D                   Input            2.286                m
     Diameter
    Ant Equiv            Asurface         10 elements            1.06#                m2
   Surface Area
    Frequency               F                   Input            450                 MHz
   Wavelength               l                   300 / F          0.666                m

 Transmit Power             P                   Input             70                  w
  Antenna Gain             Ges                  Input            14.8                dBi
      (dBi)
  Antenna Gain              G               10 Ges/10            30.2                N/A
    (factor)
        Pi                  p               Constant          3.1415927              N/A

     Antenna                h          G*l /(4*p)/Asurface
                                            2
                                                                0.4928               N/A
    Efficiency


# For a Helical Antenna with 10 elements the surface area of each element is estimated to be
0.106 m2. Total surface area is 1.06 m2.




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                                                                                      Exhibit B
                                                                              Spire Global, Inc.
                                                                        Response to Question 28
                                                                                FCC Form 312

1. Far Field Distance Calculation
The distance to the beginning of the far field can be determined from the following equation:
Distance to the Far Field Region R = 0.60 D2 / l                                 (1)
                                  ff
                                 = 4.75 m


The maximum main beam power density in the far field can be determined from the following
equation:
                                                           2
On-Axis Power Density in the      Sff = G P / (4 p Rff )                         (2)
Far Field                                      2
                                  = 7.46 W/m
                                                       2
                                  = .746 mW/cm


2. Near Field Calculation
Power flux density is considered to be at a maximum value throughout the entire length of the
defined Near Field region. The region is contained within a cylindrical volume having the same
diameter as the antenna. Past the boundary of the Near Field region, the power density from the
antenna decreases linearly with respect to increasing distance.

The distance to the end of the Near Field can be determined from the following equation:
                                          2
Extent of the Near Field          Rnf = D / (4 l)                                (3)
                                  = 1.96


The maximum power density in the Near Field can be determined from the following equation:
Near Field Power Density          Snf = 4* h* P / Asurface                       (4)
                                                   2
                                  = 130.2 W/m
                                  = 13.2 mW/cm2




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                                                                                       Exhibit B
                                                                               Spire Global, Inc.
                                                                         Response to Question 28
                                                                                 FCC Form 312

3. Transition Region Calculation
The Transition region is located between the Near and Far Field regions. The power density
begins to decrease linearly with increasing distance in the Transition region. While the power
density decreases inversely with distance in the Transition region, the power density decreases
inversely with the square of the distance in the Far Field region. The maximum power density in
the Transition region will not exceed that calculated for the Near Field region. The power density
calculated in Section 2 is the highest power density the antenna can produce in any of the regions
away from the antenna. The power density at a distance St can be determined from the following
equation:
Transition Region Power            St = Snf*Rnf / R                              (5)
                                              2
Density                            = 76 W/m
                                                   2
                                   = 7.6 mW/cm


R above is given at a halfway point (3.355m) between the edge of the near field, and the beginning
of the far field, but can be any value between Rnf and Rff.

4. Region between the Antenna and the Ground

Assuming uniform illumination of the antenna surface, the power density between the antenna
and the ground can be determined from the following equation:

Power Density between              Sg = P / Asurface                             (6)
                                                  2
Antenna and Ground                 = 66.04 W/m
                                                       2
                                   = 6.604 mW/cm




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                                                                                          Exhibit B
                                                                                  Spire Global, Inc.
                                                                            Response to Question 28
                                                                                    FCC Form 312

5. Summary of Calculations

        Table 4. Summary of Expected Radiation Levels for Uncontrolled Environment
        Region                    Calculated Maximum                  Hazard Assessment
                             Radiation Power Density Level
                                       (mW/cm2)
       Far Field                Sff                    .746             Potential Hazard
     (Rff = 4.75m)

       Near Field                   Snf                      13.2               Potential Hazard
      (Rnf=1.96m)

   Transition Region                 St                       7.6               Potential Hazard
     (Rnf<Rt<Rff)

      Between                        Sg                     6.604               Potential Hazard
 Antenna and Ground


          Table 5. Summary of Expected Radiation Levels for Controlled Environment
        Region                    Calculated Maximum                   Hazard Assessment
                              Radiation Power Density Level
                                        (mW/cm2)
       Far Field                Sff                    .746             Satisfies FCC MPE
     (Rff = 4.75m)

      Near Field                    Snf                      13.2               Potential Hazard
    (Rnf tra=1.96m)

   Transition Region                 St                       7.6               Potential Hazard
     (Rnf<Rt<Rff)

      Between                        Sg                     6.604               Potential Hazard
 Antenna and Ground



It is the applicant's responsibility to ensure that the public and operational personnel are not
exposed to harmful levels of radiation.


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                                                                                       Exhibit B
                                                                               Spire Global, Inc.
                                                                         Response to Question 28
                                                                                 FCC Form 312

6. Conclusions

Based upon the above analysis, it is concluded that FCC RF Guidelines have been exceeded in
all fields of the Uncontrolled (Table 4) environments. In the Controlled (Table 5) environments,
all regions besides the Far Field exceed the FCC RF Guidelines. The applicant proposes to
comply with the MPE limits of 0.3 mW/cm2 for the Uncontrolled Areas and the MPE limits of
1.5 mW/cm2 for the Controlled Areas.

The earth station Helical antenna will be mounted on a platform, so the applicant agrees that the
antenna is in an area secured from the public and worker personnel not familiar with the earth
station system. Non-assigned worker personnel and the general public must be accompanied by
knowledgeable earth station personnel when they enter the earth station secured area.

The earth station’s secured area will be marked with the required radiation hazard signs as
described in the recent FCC R&O 13-39. The area in the vicinity of the earth station secured area
will also have signs to inform those in the general population and those who may be working in
the area or otherwise present that they are close to a RF system capable of producing hazardous
levels.

The applicant agrees to abide by the conditions specified in Condition 5208 provided below:

       Condition 5208 - The licensee shall take all necessary measures to ensure that the
       antenna does not create potential exposure of humans to radiofrequency radiation in
       excess of the FCC exposure limits defined in 47 CFR 1.1307(b) and 1.1310 wherever
       such exposures might occur. Measures must be taken to ensure compliance with limits for
       both occupational/controlled exposure and for general population/uncontrolled
       exposure, as defined in these rule sections. Compliance can be accomplished in most
       cases by appropriate restrictions such as fencing. Requirements for restrictions can be
       determined by predictions based on calculations, modeling or by field measurements. The
       FCC's OET Bulletin 65 (available on-line at www.fcc.gov/oet/rfsafety) provides
       information on predicting exposure levels and on methods for ensuring compliance,
       including the use of warning and alerting signs and protective equipment for worker.




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Document Created: 0670-04-08 00:00:00
Document Modified: 0670-04-08 00:00:00

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