LINK BUDGET CALCULATION FOR EMWIN-N
 
Parameter Units Value
Data Rate bps 9600
Modulation Type BPSK
FEC Coding Type Conv+RS
FEC Coding Rate 0.437

Ground Uplink Transmitter
Uplink Frequency MHz 2034.70
Transmit EIRP dBmi 76.7
Antenna Pointing Loss dB 0.5

Earth - To - Space
Path Distance (for 5 deg elevation) km 41127
Free Space Loss dB 190.9
Atmospheric Attenuation dB 0.4

S/C Receive Performance
Polarization Loss dB 0.2
U/L Incident Power dBmi -115.3
Antenna Gain (from 5 deg elevation) dBi 14.8
G/T (incl cable losses) dB/K -14.2
Boltzmann constant dBm/Hz/K -198.6
Uplink Thermal C/No dB/Hz 69.1

S/C Transmit Performance
Downlink Frequency MHz 1692.70
Transmit EIRP (to 5 deg elevation) dBmi 44.8

Space - To - Earth
Path Distance (for 5 deg elevation) km 41127
Free Space Loss dB 189.3
Atmospheric Attenuation dB 0.4

Ground Downlink Receiver
Downlink Incident Power dBmi -144.90
Pwr Flux Density Rqmt (EOC in 4 kHz) dBW/m2 -154
Power Flux Density (EOC in 4 kHz) dBW/m2 -156.9
E/S G/T dB/K -0.3
Polarization Loss dB 0.2
Boltzmann constant dBm/Hz/K -198.6
Downlink Thermal C/No dB/Hz 53.2

Eb/No Overall Calculation
Overall Composite C/No dB/Hz 53.1
Data Rate in dB dB-Hz 39.8
Eb/No Calculated dB 13.3

Required Eb/No Adjustments
Required BER 1E-06
Theoretical Eb/No dB 2.6
Ground Segment Implementation Loss dB 2.0
Satellite Segment Degradations dB 1.0
Required Eb/No dB 5.6

Eb/No MARGIN dB 7.7

Some specific points for consideration:

1. The downlink power used is the 44.8 dBmi minimum.
2. The Implementation Loss of 2.0 dB is based on the performance demonstrated by the Avtec
prototype.
3. The Satellite Segment Degradations value of 1.0 dB is an estimation. Its true value will not be known
until an actual test is made through the GOES N or O transponder.
4. The bottom line margin is relatively high, but may be reduced due to items 2 and 3 above. In
addition, the steep curve of BER v. Eb/No for the FEC coding used, makes the coded link more vulnerable to
interference than a non-coded link, so some of this margin should be reserved to decrease this vulnerability. (2 dB is recommend.)