Attachment Power Flux Attach

This document pretains to SAT-PDR-20180910-00069 for Petition for Declaratory Ruling on a Satellite Space Stations filing.

IBFS_SATPDR2018091000069_1526604

            Some FCC calculations for the
                   Hiber Satellite
                                    August 24, 2018




1 Power ux density computations
A satellite is directly over the area where we want to compute the power ux
density. We assume the following values:


   •   Distance   R   between the satellite and the Earth's surface is 600km.


   •   Transmitter    PT x power   measured at the antenna port is 10W.


   •   Antenna average gain        G   is 1.4 dBi (this value has also been used in the
       link budged calculations).


   •   Channel bandwidth      BWch      is 100kHz.


   •   Bandwidth of interest       BWi   4kHz


The power ux density is dened as:

                                            PT x G
                                   Pf d =          [W/m2 ]                          (1)
                                            4πR2
with the assumed values of the variables, we have:


                           10 × 101.4/10
               Pf d =                       = 3.051 × 10−12 [W/m2 ]                 (2)
                         4π × (600 × 103 )2
   Power ux density in 1Hz bandwidth:

                                             Pdf
                            Pdf |1Hz =           [W/m2 /Hz]                         (3)
                                            BWch
   substituting proper values, the power ux density in 1Hz band:


                           3.051 × 10−12
             Pdf |1Hz =                  = 3.051 × 10−17 [W/m2 /Hz]                 (4)
                             100 × 103
   The   Pdf |1Hz   expressed in the log scale is:




                                               1


  L                                               −17
 Pdf |1Hz = 10 log(Pdf |1Hz ) = 10 log(3.051 × 10     ) = −165.16 [dBW/m2 /Hz]
                                                                                     (5)
   The power ux density in 4kHz bandwidth is (in the log domain):


 L           L                                                            2
Pdf |4kHz = Pdf |1Hz +10 log(BWi ) = −165.16+10 log(4000) = −129.14 [dBW/m /4kHz]
                                                                                     (6)



2 Power ux computation with antenna pattern
  included
The Schedule S document section Transmitting Beam lines 103 to 108, re-
quires computation of the power ux densities for dierent angle of arrivals.
Taking into account the antenna pattern described in the following document
Feasibility Report On Various 400 MHz RHCP Antenna Congurations.
                                                                                       1,
the results of computations required by the Schedule S document are presented
in Table(1). These are maximal theoretical values which will never be achieved
in a real system. I have assumed that the boresight of the antenna (-Z direction
in the antenna report is the nadir) is at 0 degrees (the Schedule S does not say
anything about it)


      Angle of arrival [deg]    Gain     Pdf |4kH [dBW/m2 /4kHz]         Remarks

                  0-5            4.6               -125.93                  (1)
                 5-10            4.6               -125.93
                 10-15           4.5               -126.03
                 15-20           4.5               -126.03
                 20-25           4.4               -126.13
                 25-90           4.4               -126.13                  (2)


         Table 1: Pfd computation as a function of an angle of arrival.


Remarks:

   1. See antenna report section 2.4 for the antenna pattern used in the calcu-
      lations.

   2. Computed for the maximum value of the gain between 25-90 deg..



3 Transmitting beam
They could some dierences in calculation results. During the development we
use an average antenna gain and NOT the peak gain. For example the power

   1 The antenna deployed on the satellite will never be use with the maximum gain due to
the reasons stated in the report(section 3.7, pp 11)



                                           2


ux density uses an average value of the gain for computations but for dierent
angles of arrival I have to use the data from the antenna pattern.



4 Receiver Beam
Computation of the C/T values assumes the maximal available gain from the
antenna. The value was computed during evaluation of the link budget (Hiber's
in-house tool). The C/T is -24.2 dB/K. For the real system the gain is 1.4dB,
and C/T is -27.4 dB/K.




                                       3



Document Created: 2018-09-06 10:52:02
Document Modified: 2018-09-06 10:52:02

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