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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