Link Analysis Program

Satellite LinkBuget Terms

� SSPA Output Power (dBm)

�� The carrier output power from the earth station SSPA.

�� (Note: this is NOT the SSPA rated power).

� Transmitter Antenna Diameter (metres)

�� The diameter of the transmitting earth station antenna.

� Transmitter Antenna Gain (dB)

�� The gain of the transmitting earth station antenna at the current

�� uplink frequency.

� Transmitter Antenna Efficiency (%)

�� The efficiency of the transmitting earth station antenna at the current

�� uplink frequency.

� Uplink Frequency (GHz)

�� The actual transmitted RF carrier frequency.� This figure is used to

�� calculate antenna performance and uplink path loss.

� Transmitter Latitude (deg)

�� The latitude of the transmitting antenna site.� Enter northern latitudes

�� as positive numbers and southern latitudes as negative numbers.

� Transmitter Longitude (deg)

�� The longitude of the transmitting antenna site.� Enter eastern

�� longitudes as positive numbers and western longitudes as negative

�� numbers.

� Transmitter Site Name

�� The location name of the transmitting earth station.

� Tx Bit Rate at Modem Input (k bit/s)

�� The data rate presented to the modem input.� This will generally be

�� n x 64 kbps.

� Overhead bits (for IBS) (%)

�� The overhead bit rate (in %) for the IBS modem.� When the IBS modem

�� type is first selected, this figure is automatically set to 6.67%

�� (i.e. 1/15), the standard value for an INTELSAT IESS309 IBS modem.

�� It may be changed manually, but will be reset if the modem type is

�� changed and then reset to IBS, or if the IDR modem is selected and

�� the data rate is set to less than 1544kbps.

� Overhead bits (for IDR>1544k) (k bit/s)

�� The overhead bit rate for the IDR modem.� When the IDR modem type is

�� first selected, this figure is automatically set to 96kbps, the standard

�� value for an INTELSAT IESS308 IDR modem. If a data rate of 1544kbps or

�� lower is entered for the IDR modem, the IBS modem overhead percentage

�� rate (12 above) is used instead.� This follows INTELSAT IESS308 standard

�� practice.� It may be changed manually, but will be reset if the modem

�� type is changed and then reset to IDR (provided the data rate is set

�� to greater than 1544kbps).

� FEC Rate (0, 0.5, 0.75)

�� The Forward Error Correction rate.� For no error correction, use a

�� figure of 0.� For rate 1/2, use 0.5 and rate 3/4 use 0.75.

� Uplink Fade Margin (dB)

�� The required fade margin for the uplink.

� Uplink Antenna Pointing Loss (dB)

�� The loss due to antenna mispointing.� Other losses (e.g. SSPA output

�� power fall with time) may also be included in this figure.

� U/L Adjacent Transponder C/I (dB)

� U/L Adjacent Xpndr X-Pol C/I (dB)

� U/L Adjacent Satellite C/I (dB)

�� The uplink carrier to interference noise ratios (in the occupied

�� bandwidth

�Satellite Name

�� The name of the satellite being used.

� Transponder Bandwidth (MHz)

�� The bandwidth of the transponder being used.�

� Satellite G/T (dB/K)

�� The satellite G/T in the direction of the transmitting earth station.

�� Refer to the satellite operator's G/T contour maps.

� Satellite Satn. Flux Density (dBW/msq)

�� The satellite saturation flux density in the direction of the

�� transmitting earth station.� Generally, the satellite operator only

�� provides the saturation flux density figure at the beam centre.� If the

�� transmitting earth station is not at the beam centre, the saturation

�� flux density figure given should be reduced by the reduction in G/T

�� from the beam centre to the actual earth station location.� (Refer to

�� the satellite operator's G/T contour maps).

� Satellite EIRP (dBW)

�� The satellite saturation EIRP in the direction of the receiving earth

�� station.� Refer to the satellite operator's EIRP contour maps.

� Satellite Longitude (deg)

�� The longitude of the satellite.� Enter eastern longitudes as positive

�� numbers and western longitudes as negative numbers.

� Aggregated Input Back-Off (dB)

�� The total combined (i.e. aggregated) input back-off operating point for

�� the transponder when operating in a multi-carrier mode (

� Aggregated Output Back-Off (dB)

�� The total combined (i.e. aggregated) output back-off operating point for

�� the transponder when operating in a multi-carrier mode. The difference between

� the aggregated IPBO and OPBO figures will also be the difference between the

�� "per carrier" IPBO and OPBO figures.

� Satellite Transponder C/I'Mod (dB)

�� The TWTA output carrier to intermodulation noise ratio (in the occupied

�� bandwidth - i.e. modem noise bandwidth).

��

�Downlink Fade Margin� (dB)

�� The required fade margin for the downlink.

�Downlink Antenna Pointing Loss (dB)

�� The loss due to antenna mispointing.

�D/L Adjacent Transponder C/I (dB)

�D/L Adjacent Xpndr X-Pol C/I (dB)

�D/L Adjacent Satellite C/I (dB)

�� The downlink carrier to interference noise ratios (in the occupied

�� bandwidth - i.e. modem noise bandwidth) for the sources indicated.

��

�Receiver Antenna Diameter (m)

�� The diameter of the receiving earth station antenna.

�Receiver Antenna Gain (dB)

�� The gain of the receiving earth station antenna at the current

�� downlink frequency.

�Receiver Antenna Efficiency (%)

�� The efficiency of the receiving earth station antenna at the current

�� downlink frequency.

��

�Receiver Antenna Temp (K)

�� The receiving antenna noise temperature.� This figure is given by the

�� antenna manufacturer.� The exact figure will depend upon the antenna

�� elevation angle.

�Receiver G/T (dB/K)

�� The receiver G/T.� This figure may be changed manually, but will be

�� automatically recalculated from the antenna parameters and noise

�� temperature/figure parameters if any of these are changed.

�Receiver Noise Temperature (K)

�� The noise temperature of the receiver.� If this figure is changed

�� manually, the receiver noise figure is automatically recalculated

�� from the new noise temperature.� If the receiver G/T is changed

�� manually, the receiver noise temperature and noise figure are both

�� recalculated from the antenna gain and noise temperature and the

�� new G/T figure.

�Downlink Frequency (GHz)

�� The actual received RF carrier frequency.� This figure is used to

�� calculate antenna performance and downlink path loss.

�Receiver Latitude (deg)

�� The latitude of the receiving antenna site.� Enter northern latitudes

�� as positive numbers and southern latitudes as negative numbers.

�Receiver Longitude (deg)

�� The longitude of the receiving antenna site.� Enter eastern

�� longitudes as positive numbers and western longitudes as negative

�Receiver Site Name

�� The location name of the receiving earth station.

�Transmitter Antenna Elevation (deg)

�� The elevation angle of the transmitting antenna.� Calculated from the

�� transmitting earth station location and the satellite location.

�Transmitter Antenna Azimuth (deg)

�� The azimuth angle of the transmitting antenna.� Calculated from the

�� transmitting earth station location and the satellite location.

�Receiver Antenna Elevation (deg)

�� The elevation angle of the receiving antenna.� Calculated from the

�� receiving earth station location and the satellite location.

�Receiver Antenna Azimuth (deg)

�� The azimuth angle of the receiving antenna.� Calculated from the

�� receiving earth station location and the satellite location.

�Earth Station EIRP (dBW)

�� The transmitting earth station EIRP, calculated from the SSPA output

�� power and the antenna gain.

�Total Uplink Loss (dB)

�� The loss on the uplink path at the transmitting frequency, calculated

�� from the transmitting earth station location to the satellite location

�� plus the Uplink Antenna Pointing Loss.

�Flux Density at Satellite (dBW/msq)

�� The power flux density at the satellite receive antenna, calculated

�� from the earth station EIRP and the total uplink loss.

�Uplink Thermal C/No (dB-Hz)

�� The C/No at the satellite due solely to the G/T performance of the

�� satellite.� Calculated from the transmitting earth station EIRP, the

�� total uplink loss and the satellite G/T.

�Uplink Interference C/Io (dB-Hz)

�� The total uplink carrier to interference noise density ratio for the

�� actual carrier level (i.e. flux density) at the satellite.

�Intermodulation C/Io (dB-Hz)

�� The carrier to intermodulation noise density ratio for the actual

�� carrier level transmitted from the satellite.

�Downlink Interference C/Io (dB-Hz)

�� The total downlink carrier to interference noise density ratio for the

�� actual carrier level transmitted from the satellite.

�EIRP Radiated from Satellite (dBW)

�� The actual carrier power transmitted from the satellite.� Calculated

�� from the TWTA saturation EIRP and OPBO.

�Total Downlink Loss (dB)

�� The loss on the downlink path at the receiving frequency, calculated

�� from the receiving earth station location to the satellite location

�� plus the Downlink Antenna Pointing Loss.

�Downlink Thermal C/No (dB-Hz)

�� The C/No at the receiving earth station due solely to the G/T

�� performance of the earth station.� Calculated from the satellite EIRP,

�� the total downlink loss and the earth station G/T.

�Carrier/Noise Density (dB-Hz)

�� The total received signal C/No, taking into account the uplink and

�� downlink thermal C/No figures and all the interference C/Io figures.

�Carrier/Noise Ratio (dB)

�� The C/No figure converted to C/N using the IF noise bandwidth of the

�� selected modem.

�Eb/No (dB)

�� The Eb/No figure calculated from the received signal C/No and the

�� input data plus overhead data rate. (i.e. excluding FEC).