Attachment Power Density Calc. SES-MOD-20120601-00479

Attachment Power Density Calc.

This document pretains to SES-MOD-20120601-00479 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2012060100479_951910

$Power Density Calculations Exhibit B - Page 2 of 8 POWER DENSITY CALCULATIONS FOR TRANSMITTED SIGNALS FROM KU-BAND SATELLITE EARTH STATION I. SIGNAL TYPES AND BANDWIDTHS At any given time during the operation of the Ku-band satellite earth station, one or more of the following signal types will be uplinked to a selected satellite within the domestic arc. Signal Type Occupied Signal Bandwidth 1 Digital QPSK (medium-rate SCPC 4.50 MHz compressed digital video) 2 Digital QPSK (medium-rate SCPC 6.00 MHz compressed digital video) 3 Digital QPSK (medium-rate SCPC 9.00 MHz compressed digital video) II. SIGNAL COMBINATIONS AND PER-CARRIER POWER LEVELS Current operational plans for the Ku-band satellite earth station include various combinations of the following uplinked signals: • One or more medium-rate SCPC compressed digital video signals, with per-carrier RF power density levels (into the antenna) that will not exceed -14.0 dBW/4 kHz. III. INPUT POWER LEVELS AND POWER DENSITIES (TO ANTENNA) For any of the possible transmitted signal types, the RF power density into the antenna is given by: Power Density (dBW/4 kHz) = P (dBW) + 36.0 dB-Hz - 10 log B + PF, where P = per-carrier input power (to the antenna) 36.0 dB-Hz is a factor to convert power density from a 1 Hz bandwidth to a 4 kHz bandwidth B is the bandwidth occupied by the signal PF = signal peaking factor (dependent on the signal type) The per-carrier input power (to the antenna) is determined by reducing the per-carrier output power from the HPA by the transmitting system losses, or P (dBW) = Pt (dBW) + Lt (dB) where P t = per-carrier output power (from the HPA) and Lt = transmitting system losses (a fractional numeric, with a negative dB value) For routine licensing of Ku-band narrowband digital transmissions from antennas less than 5 meters in diameter, it is understood that the per-carrier power density into the antenna should be no greater than -14.0 dBW/4 kHz. No specific additional constraints/limitations related to transmitted power levels (or power densities) of narrowband digital signals at Ku-band are known to exist.$

Power Density Calculations Exhibit B - Page 3 of 8

As shown below, all signals to be transmitted from the Ku-band satellite earth station will be operated
in strict compliance with all known applicable limitations on input power levels and input power densities for
Ku-band signals. Maximum power levels are established for the signal type listed in Section I, and input
power densities are calculated for it. Maximum EIRP and EIRP density levels, both on-axis and toward
the horizon, are also calculated for the specified signal type.

A. MEDIUM-RATE SCPC COMPRESSED DIGITAL VIDEO SIGNALS (Type 1)

1 Input Power Level (to antenna)

For the Ku-band satellite earth station, the maximum operating power level (at the output of the HPA)
for a medium-rate SCPC compressed digital video signal will never exceed 40 Watts, or 16.0 dBW.
Using a minimum value of 1.0 dB for the aggregate transmitting system losses, the
corresponding maximum power level into the antenna will therefore be:

P (dBW) = Pt (dBW) + Lt (dB)

= 16.0 dBW - 1 dB
= 15.0

A per-carrier operating input power level of 15.0 dBW will be substantially above what will be
required for good performance margins to a network of 1.2-meter to 3.7-meter receiving antennas.
Such a high power level will normally only be used during occasional periods of uplink degradation due to rainfall.

2 Input Power Density (to antenna)

Assuming a maximum antenna input power level of 15.0 dBW, the worst-case input power density
for the medium-rate SCPC compressed digital video signal can be determined. This signal is in the
MPEG2/DVB SCPC format, with an information rate of 5.19 Mbps. Use of 3/4 FEC encoding
results in a transmitted data rate of approximately 6.92 Mbps. The modulation technique is QPSK
and the transmitted symbol rate is approximately 3.46 Msps. The occupied signal bandwidth is approximately
4.50 Mhz, but (for conservatism) an even lower bandwidth equal to the symbol rate of
3.46 MHz, or 65.39 dB-Hz, will be used to calculate the input power density
to the antenna. For this bandwidth, a peaking factor of 0.0 dB can be safely assumed, and the calculation is as follows:

Input Power Density (dBW/4 kHz) = P (dBW) + 36.0 dB-Hz - 10 log B + PF
= 15.0 dBW + 36.0 dB-Hz - 65.39 dB-Hz + 0.0 dB
= -14.37 dBW/4 kHz

Under no circumstances will the input power density (to the antenna) of the specified medium-rate
SCPC compressed digital video signal be permitted to exceed -14.0 dBW/4 kHz.

Power Density Calculations Exhibit B - Page 4 of 8

B. MEDIUM-RATE SCPC COMPRESSED DIGITAL VIDEO SIGNALS (Type 2)

1 Input Power Level (to antenna)

For the Ku-band satellite earth station, the maximum operating power level (at the output of the HPA)
for a medium-rate SCPC compressed digital video signal will never exceed 55 Watts, or 17.4 dBW.
Using a minimum value of 1 dB for the aggregate transmitting system losses, the
corresponding maximum power level into the antenna will therefore be:

P (dBW) = Pt (dBW) + Lt (dB)

= 17.4 dBW - 1 dB
= 16.4

A per-carrier operating input power level of 16.4 dBW will be substantially above what will be
required for good performance margins to a network of 1.2-meter to 3.7-meter receiving antennas.
Such a high power level will normally only be used during occasional periods of uplink degradation due to rainfall.

2 Input Power Density (to antenna)

Assuming a maximum antenna input power level of 16.4 dBW, the worst-case input power density
for the medium-rate SCPC compressed digital video signal can be determined. This signal is in the
MPEG2/DVB SCPC format, with an information rate of 6.9 Mbps. Use of 3/4 FEC encoding
results in a transmitted data rate of approximately 9.20 Mbps. The modulation technique is QPSK
and the transmitted symbol rate is approximately 4.60 Msps. The occupied signal bandwidth is approximately
5.98 Mhz, but (for conservatism) an even lower bandwidth equal to the symbol rate of
4.60 MHz, or 66.63 dB-Hz, will be used to calculate the input power density
to the antenna. For this bandwidth, a peaking factor of 0.0 dB can be safely assumed, and the calculation is as follows:

Input Power Density (dBW/4 kHz) = P (dBW) + 36.0 dB-Hz - 10 log B + PF
= 16.4 dBW + 36.0 dB-Hz - 66.63 dB-Hz + 0.0 dB
= -14.22 dBW/4 kHz

Under no circumstances will the input power density (to the antenna) of the specified medium-rate
SCPC compressed digital video signal be permitted to exceed -14.0 dBW/4 kHz.

Power Density Calculations Exhibit B - Page 5 of 8

C. MEDIUM-RATE SCPC COMPRESSED DIGITAL VIDEO SIGNALS (Type 3)

1 Input Power Level (to antenna)

For the Ku-band satellite earth station, the maximum operating power level (at the output of the HPA)
for a medium-rate SCPC compressed digital video signal will never exceed 85 Watts, or 19.3 dBW.
Using a minimum value of 1 dB for the aggregate transmitting system losses, the
corresponding maximum power level into the antenna will therefore be:

P (dBW) = Pt (dBW) + Lt (dB)

= 19.3 dBW - 1 dB
= 18.3

A per-carrier operating input power level of 18.3 dBW will be substantially above what will be
required for good performance margins to a network of 1.2-meter to 3.7-meter receiving antennas.
Such a high power level will normally only be used during occasional periods of uplink degradation due to rainfall.

2 Input Power Density (to antenna)

Assuming a maximum antenna input power level of 18.3 dBW, the worst-case input power density
for the medium-rate SCPC compressed digital video signal can be determined. This signal is in the
MPEG2/DVB SCPC format, with an information rate of 10.38 Mbps. Use of 3/4 FEC encoding
results in a transmitted data rate of approximately 13.84 Mbps. The modulation technique is QPSK
and the transmitted symbol rate is approximately 6.92 Msps. The occupied signal bandwidth is approximately
9.00 Mhz, but (for conservatism) an even lower bandwidth equal to the symbol rate of
6.92 MHz, or 68.40 dB-Hz, will be used to calculate the input power density
to the antenna. For this bandwidth, a peaking factor of 0.0 dB can be safely assumed, and the calculation is as follows:

Input Power Density (dBW/4 kHz) = P (dBW) + 36.0 dB-Hz - 10 log B + PF
= 18.3 dBW + 36.0 dB-Hz - 68.40 dB-Hz + 0.0 dB
= -14.11 dBW/4 kHz

Under no circumstances will the input power density (to the antenna) of the specified medium-rate
SCPC compressed digital video signal be permitted to exceed -14.0 dBW/4 kHz.

Power Density Calculations Exhibit B - Page 6 of 8

IV. TRANSMITTED EIRPs AND EIRP DENSITIES (FROM ANTENNA)

For the Ku-band satellite earth station, the maximum (on-axis) value of per-carrier EIRP is calculated as follows:

EIRP (dBW) = Pt (dBW) + Lt (dB) + Gt (dBi) ,

where Pt = maximum value of per-carrier power (from the HPA)

Lt = minimum value of transmitting system losses = - 1.0 dB

Gt = maximum value of transmit antenna gain = 53 dBi

For a given transmitted signal, the maximum (on-axis) RF power density (at the output of the antenna) is given by:

EIRP Density (dBW/4 kHz) = EIRP (dBW) + 36.0 dB-Hz - 10 log B + PF,

where EIRP = maximum (on-axis) value of per-carrier output EIRP

36.0 dB-Hz is a factor to convert power density from a 1 Hz
bandwidth to a 4 kHz bandwidth
B is the bandwidth occupied by the signal

PF = signal peaking factor (dependent on the signal type)

Equivalently, maximum (on-axis) EIRP density values can be determined by simply increasing the maximum values of per-carrier input
power density (determined previously for each signal type) by the on-axis antenna gain.

At any off-axis angle, the EIRP and EIRP density values will be reduced by an amount equal to the antenna gain reduction. For any
given transmitted signal type from the Ku-band satellite earth station being considered, the maximum EIRP density toward the horizon
will occur when the elevation angle is at its minimum value of 18 degrees. At an off-axis angle of 18 degrees, the antenna
gain will be no greater than the allowable sidelobe envelope. At this angle, the off-axis gain will therefore be no greater than:

29 - 25log ( 18 deg) = -2.4 dBi

The gain reduction at an off-axis angle of 18 degrees will be equal to the difference in on-axis and off-axis gain values, and will
be at least:
53 dBi - -2.4 dBi = 55.4 dB

Power Density Calculations Exhibit B - Page 7 of 8

A. MEDIUM-RATE SCPC COMPRESSED DIGITAL VIDEO SIGNALS (Type 1)

1 Maximum EIRP (on-axis)

Assuming that per-carrier input power level (to the antenna) is increased up to its maximum allowable value of
15.0 dBW, the maximum EIRP for the specified medium-rate SCPC compressed digital video signal can be determined as follows:

EIRP (dBW) = Pt (dBW) + Lt (dB) + Gt (dBi) ,

= 16.0 dBW - 1 dB + 53 dBi

= 68.0 dBW

2 Maximum EIRP Density (on-axis)

EIRP Density (dBW/4 kHz) = EIRP (dBW) + 36.0 dB-Hz - 10 log B + PF

= 68.0 dBW + 36.0 dB-Hz - 65.39 dB-Hz + 0.0 dB

= 38.6 dBW/4 kHz

3. Maximum EIRP Density (toward horizon)

EIRP Density (at 18 degrees) = EIRP Density (on-axis) - 55.4 dB

= 38.6 dBW/4 kHz - 55.4 dB

= -16.8 dBW/4 kHz

B. MEDIUM-RATE SCPC COMPRESSED DIGITAL VIDEO SIGNALS (Type 2)

1 Maximum EIRP (on-axis)

Assuming that per-carrier input power level (to the antenna) is increased up to its maximum allowable value of
16.4 dBW, the maximum EIRP for the specified medium-rate SCPC compressed digital video signal can be determined as folmediums:

EIRP (dBW) = Pt (dBW) + Lt (dB) + Gt (dBi) ,

= 17.4 dBW - 1 dB + 53 dBi

= 69.4 dBW

2 Maximum EIRP Density (on-axis)

EIRP Density (dBW/4 kHz) = EIRP (dBW) + 36.0 dB-Hz - 10 log B + PF

= 69.4 dBW + 36.0 dB-Hz - 66.63 dB-Hz + 0.0 dB

= 38.8 dBW/4 kHz

3. Maximum EIRP Density (toward horizon)

EIRP Density (at 18 degrees) = EIRP Density (on-axis) - 55.4 dB

= 38.8 dBW/4 kHz - 55.4 dB

= -16.6 dBW/4 kHz

Power Density Calculations Exhibit B - Page 8 of 8

C. MEDIUM-RATE SCPC COMPRESSED DIGITAL VIDEO SIGNALS (Type 3)

1 Maximum EIRP (on-axis)

Assuming that per-carrier input power level (to the antenna) is increased up to its maximum allowable value of
18.3 dBW, the maximum EIRP for the specified medium-rate SCPC compressed digital video signal can be determined as follows:

EIRP (dBW) = Pt (dBW) + Lt (dB) + Gt (dBi) ,

= 19.3 dBW - 1 dB + 53 dBi

= 71.3 dBW

2 Maximum EIRP Density (on-axis)

EIRP Density (dBW/4 kHz) = EIRP (dBW) + 36.0 dB-Hz - 10 log B + PF

= 71.3 dBW + 36.0 dB-Hz - 68.40 dB-Hz + 0.0 dB

= 38.9 dBW/4 kHz

3. Maximum EIRP Density (toward horizon)

EIRP Density (at 18 degrees) = EIRP Density (on-axis) - 55.4 dB

= 38.9 dBW/4 kHz - 55.4 dB

= -16.5 dBW/4 kHz

V. SUMMARY OF RESULTS

Maximum Maximum
Minimum Maximum Input Maximum Maximum EIRP
Signal Signal Input Power On-Axis On-Axis Density
Type Bandwidth* Power to Density to EIRP EIRP Toward
(MHz) Antenna Antenna (dBW) Density Horizon
(dBW) (dBW/4kH (dBW/4kHz (dBW/4kHz
z) ) )
Digital 3.46 15.0 -14.37 68.0 38.6 -16.8
(Type 1)
Digital 4.60 16.4 -14.22 69.4 38.8 -16.6
(Type 2)
Digital 6.92 18.3 -14.11 71.3 38.9 -16.5
(Type 3)

*Symbol rate bandwidth (very conservative assumption).

VI. CONCLUSIONS

The analyses presented herein, and summarized in the preceding table, show that the maximum
power levels and maximum power density values (for all of the possible signal types) are all within
the values that are considered applicable for routine licensing of Ku-band transmit/receive earth stations.

Document Created: 2012-05-04 14:53:14
Document Modified: 2012-05-04 14:53:14