Pro ty, kteří se zajímají jak snadné je dospět k výpočtu vysílacího výkonu pro satelitní spoj vzhledem k velikostem antén, parametrům satelitu a geografickému umístění obou konců spoje, samozřejmě s přihlédnutím k přenosové rychlosti a vyváženosti poměru odebírané energie a zabraného pásma na satelitním transpondéru. Jako příklad je zvolen spoj z Prahy do Mali v Africe, protože jde z hlediska srážek o rozdílné oblasti a je třeba brát do úvahy srážkové úhrny vzhledem k dostupnosti spoje.
| Service Name |
INTV |
| Coverage |
EU/Afrika |
| Uplink earth station |
Praha, Czech Republic |
| Downlink earth station |
Mali |
| Satellite name |
W21B |
| Modcod |
Manual |
| Link Input Parameters |
Up |
Down |
|
Units |
| Site latitude |
50.08N |
13N |
|
degrees |
| Site longitude |
14.42E |
8.0W |
|
degrees |
| Site altitude |
0.330 |
0.000 |
|
km |
| Frequency |
14.02 |
12.7 |
|
GHz |
| Polarization |
Vertical |
Horizontal |
|
| Rain model |
ITU-R |
ITU-R |
|
| Rain zone or mm/h |
35.1 |
54.7 |
| Availability (average year) |
99.8 |
99.8 |
|
% |
| Antenna aperture |
3.7 |
1.8 |
|
metres |
| Antenna efficiency or gain (+ or – prefix) |
55 |
59 |
|
% or dBi |
| Coupling loss |
1 |
0.1 |
|
dB |
| Antenna mispoint loss |
0.5 |
0.5 |
|
dB |
| Other path losses |
0 |
0 |
|
dB |
| LNB noise figure or temp (+ prefix) |
|
0.8 |
|
dB or K |
| Antenna noise |
|
45.89 |
|
K |
| Csat/ACIo |
119.77 |
110 |
|
dB.Hz |
| Csat/ASIo |
122.50 |
122.50 |
|
dB.Hz |
| Csat/XPIo |
144.77 |
120.97 |
|
dB.Hz |
| Uplink station HPA output back-off |
0.5 |
|
|
dB |
| Uplink power control |
0 |
|
|
dB |
| Number of carriers / HPA |
1 |
|
|
| HPA C/IMo |
141.97 |
|
|
dB.Hz |
| Required HPA power |
MIN |
|
|
W |
| Satellite Input Parameters |
Value |
|
|
Units |
| Satellite longitude |
21.6E |
|
|
degrees |
| Transponder type |
TWTA |
|
|
| G/T Reference |
0 |
|
|
dB/K |
| SFD Reference |
-82.8 |
|
|
dBW/m2 |
| Receive G/T |
0.4 |
|
|
dB/K |
| Attenuator pad (gain step) |
0 |
|
|
dB |
| Effective SFD |
-83.20 |
|
|
dBW/m2 |
| Satellite ALC |
0 |
|
|
dB |
| EIRP (saturation) |
49.8 |
|
|
dBW |
| Transponder bandwidth |
72 |
|
|
MHz |
| Input back off total |
5.5 |
|
|
dB |
| Output back off total |
3.70 |
|
|
dB |
| C/IM |
24.00 |
|
|
dB |
| Carrier/Link Input Parameters |
Value |
|
|
Units |
| Modulation |
4-PSK |
|
|
| Required Eb/No |
4.2 |
|
|
dB |
| Information rate |
1.024 |
|
|
Mbps |
| Information rate overhead |
0 |
|
|
% |
| FEC code rate |
3/4 |
|
|
| Spreading gain |
0 |
|
|
dB |
| (1 + Roll off factor) |
1.35 |
|
|
| Carrier spacing factor |
1.3 |
|
|
| Bandwidth allocation step size |
0.01 |
|
|
MHz |
| Implementation loss |
0.5 |
|
|
dB |
| System margin |
1 |
|
|
dB |
| Calculations at Saturation |
Value |
|
|
Units |
| Gain 1m^2 |
44.39 |
|
|
dB/m2 |
| Uplink C/No |
101.41 |
|
|
dB.Hz |
| Downlink C/No |
96.71 |
|
|
dB.Hz |
| Total C/No |
95.45 |
|
|
dB.Hz |
| Uplink EIRP for saturation |
80.13 |
|
|
dBW |
| General Calculations |
Up |
Down |
|
Units |
| Elevation |
32.21 |
52.65 |
|
degrees |
| True azimuth |
170.67 |
111.60 |
|
degrees |
| Compass bearing |
167.16 |
115.94 |
|
degrees |
| Path distance to satellite |
38417.41 |
36914.37 |
|
km |
| XPD during rain |
38.20 |
29.77 |
|
dB |
| Propagation time delay |
0.128146 |
0.123133 |
|
seconds |
| Antenna efficiency |
55.00 |
59.00 |
|
% |
| Antenna gain |
52.11 |
45.30 |
|
dBi |
| Availability (average year) |
99.8 |
99.8 |
|
% |
| Link downtime (average year) |
17.532 |
17.532 |
|
hours |
| Availability (worst month) |
99.297 |
99.297 |
|
% |
| Link downtime (worst month) |
5.134 |
5.134 |
|
hours |
| Maximum availability at current HPA power |
99.9735 |
99.7999 |
|
% |
| Minimum antenna size at current HPA power |
|
1.8000 |
|
metres |
| Uplink Calculation |
Clear |
Rain Up |
Rain Dn |
Units |
| Uplink transmit EIRP |
55.13 |
55.13 |
55.13 |
dBW |
| Transponder input back-off (total) |
5.50 |
5.50 |
5.50 |
dB |
| Input back-off per carrier |
25.00 |
27.19 |
25.00 |
dB |
| Antenna mispoint |
0.50 |
0.50 |
0.50 |
dB |
| Free space loss |
207.07 |
207.07 |
207.07 |
dB |
| Atmospheric absorption |
0.15 |
0.22 |
0.15 |
dB |
| Tropospheric scintillation fading |
0.00 |
0.26 |
0.00 |
dB |
| Cloud attenuation |
0.00 |
0.38 |
0.00 |
dB |
| Rain attenuation |
0.00 |
1.72 |
0.00 |
dB |
| Total attenuation (gas-rain-cloud-scintillation) |
0.15 |
2.34 |
0.15 |
dB |
| Other path losses |
0.00 |
0.00 |
0.00 |
dB |
| Uplink power control |
0.00 |
0.00 |
0.00 |
dB |
| Uncompensated fade |
0.00 |
2.20 |
0.00 |
dB |
| C/No (thermal) |
76.41 |
74.22 |
76.41 |
dB.Hz |
| C/N (thermal) |
18.07 |
15.87 |
18.07 |
dB |
| C/ACI |
36.43 |
34.24 |
36.43 |
dB |
| C/ASI |
39.16 |
36.97 |
39.16 |
dB |
| C/XPI |
61.43 |
38.18 |
61.43 |
dB |
| C/IM |
58.63 |
58.63 |
58.63 |
dB |
| C/(N+I) [ = Es/(No+Io) ] |
17.97 |
15.75 |
17.97 |
dB |
| Eb/(No+Io) |
16.21 |
13.99 |
16.21 |
dB |
| Downlink Calculation |
Clear |
Rain Up |
Rain Dn |
Units |
| Satellite EIRP total |
49.80 |
49.80 |
49.80 |
dBW |
| Transponder output back-off (total) |
3.70 |
3.70 |
3.70 |
dB |
| Output back-off per carrier |
23.20 |
25.39 |
23.20 |
dB |
| Satellite EIRP per carrier |
26.60 |
24.41 |
26.60 |
dBW |
| Antenna mispoint |
0.50 |
0.50 |
0.50 |
dB |
| Free space loss |
205.87 |
205.87 |
205.87 |
dB |
| Atmospheric absorption |
0.10 |
0.10 |
0.14 |
dB |
| Tropospheric scintillation fading |
0.00 |
0.00 |
0.23 |
dB |
| Cloud attenuation |
0.00 |
0.00 |
0.44 |
dB |
| Rain attenuation |
0.00 |
0.00 |
3.05 |
dB |
| Total attenuation (gas-rain-cloud-scintillation) |
0.10 |
0.10 |
3.64 |
dB |
| Other path losses |
0.00 |
0.00 |
0.00 |
dB |
| Noise increase due to precipitation |
0.00 |
0.00 |
3.59 |
dB |
| Downlink degradation (DND) |
0.00 |
0.00 |
7.13 |
dB |
| Total system noise |
110.10 |
110.10 |
251.74 |
K |
| Figure of merit (G/T) |
24.78 |
24.78 |
21.19 |
dB/K |
| C/No (thermal) |
73.52 |
71.32 |
66.39 |
dB.Hz |
| C/N (thermal) |
15.18 |
12.98 |
8.04 |
dB |
| C/ACI |
28.46 |
26.27 |
28.46 |
dB |
| C/ASI |
40.96 |
38.77 |
40.96 |
dB |
| C/XPI |
39.43 |
37.24 |
29.54 |
dB |
| C/IM |
24.00 |
24.00 |
24.00 |
dB |
| C/(N+I) [ = Es/(No+Io) ] |
14.44 |
12.44 |
7.86 |
dB |
| Eb/(No+Io) |
12.68 |
10.68 |
6.10 |
dB |
| Totals per Carrier (End-to-End) |
Clear |
Rain Up |
Rain Dn |
Units |
| C/No (thermal) |
71.72 |
69.52 |
65.97 |
dB.Hz |
| C/N (thermal) |
13.38 |
11.18 |
7.63 |
dB |
| C/ACI |
27.82 |
25.62 |
27.82 |
dB |
| C/ASI |
36.96 |
34.76 |
36.96 |
dB |
| C/XPI |
39.40 |
34.67 |
29.54 |
dB |
| C/IM |
24.00 |
24.00 |
24.00 |
dB |
| C/I (total) |
22.25 |
21.31 |
21.58 |
dB |
| C/(No+Io) |
71.19 |
69.12 |
65.80 |
dB.Hz |
| C/(N+I) [ = Es/(No+Io) ] |
12.85 |
10.78 |
7.46 |
dB |
| Eb/(No+Io) |
11.09 |
9.02 |
5.70 |
dB |
| Implementation loss |
0.50 |
0.50 |
0.50 |
dB |
| System margin |
1.00 |
1.00 |
1.00 |
dB |
| Net Eb/(No+Io) |
9.59 |
7.52 |
4.20 |
dB |
| Required Eb/(No+Io) |
4.20 |
4.20 |
4.20 |
dB |
| Excess margin |
5.39 |
3.32 |
0.00 |
dB |
| EIRP Density Calculations |
Clear |
Rain Up |
Rain Dn |
Units |
| Flange transmit (up) |
-55.32 |
-55.32 |
-55.32 |
dBW/Hz |
| Satellite (down) |
-31.74 |
-33.93 |
-31.74 |
dBW/Hz |
| Flange receive (down) |
-192.41 |
-194.60 |
-199.54 |
dBW/Hz |
| Earth Station Power Requirements |
Value |
|
|
Units |
| EIRP per carrier |
55.13 |
|
|
dBW |
| Antenna gain |
52.11 |
|
|
dBi |
| Antenna feed flange power per carrier |
3.02 |
|
|
dBW |
| Uplink power control |
0.00 |
|
|
dB |
| HPA output back off |
0.50 |
|
|
dB |
| Waveguide loss |
1 |
|
|
dB |
| Number of HPA carriers |
1 |
|
|
| Total HPA power required |
4.5240 |
|
|
dBW |
| Required HPA power |
2.8340 |
|
|
W |
| Space Segment Utilization |
Value |
|
|
Units |
| Overall availability |
99.6004 |
|
|
% |
| Information rate |
1.0240 |
|
|
Mbps |
| Information rate (inc overhead) |
1.0240 |
|
|
Mbps |
| Transmit rate |
1.3653 |
|
|
Mbps |
| Symbol rate |
0.6827 |
|
|
Mbaud |
| Noise Bandwidth |
58.34 |
|
|
dB.Hz |
| Occupied bandwidth |
0.9216 |
|
|
MHz |
| Minimum allocated bandwidth required |
0.8875 |
|
|
MHz |
| Allocated transponder bandwidth |
0.8900 |
|
|
MHz |
| Link efficiency |
1.151 |
|
|
bps/Hz |
| Percentage transponder bandwidth used |
1.24 |
|
|
% |
| Used transponder power |
26.60 |
|
|
dBW |
| Percentage transponder power used |
1.12 |
|
|
% |
| Max carriers / transponder |
80.90 |
| Limited by: |
Bandwidth |
| Power equivalent bandwidth usage |
0.8086 |
|
|
MHz |