UPLINK BUDGET
Modulation Type: GFSK at 500 bps and Fdev=1kHz
Table 1: Uplink Budget Analysis
| Frequency: | 437.5 | MHz | ||
| Distance: | 815 | km | at 35 Degrees | |
| Transmit Power: | 14 | W | ||
| 11.46128036 | dBW | |||
| GS | Transmit Antenna Gain: | 12 | dBi | |
| EIRP: | 23.46128036 | dBW | Power+Antenna Gain | |
| Transmission Loss at GS | 2 | dB | ||
| Uplink Path | Free Space Path Loss: | 143.4727133 | dB | 32.4+20log(d)+20log(f) |
| Antenna Pointing Loss: | 1 | dB | ||
| Antenna Polorization Loss: | 1 | dB | ||
| Atmospheric Loss: | 2 | dB | ||
| Ionospheric Loss: | 1 | dB | ||
| Rain Loss: | 0 | dB | ||
| Spacecraft | Isotropic Signal Level at Spacecraft | -127.011433 | dB | EIRP-Losses |
| Spacecraft Antenna Pointing Loss | 0.2 | dB | ||
| Spacecraft Antenna Gain | 2.2 | dBi | ||
| Spacecraft Line Loss | 1 | dB | ||
| Receiver Sensitivity | -115 | dBm | ||
| Receiver Sensitivity | -145 | dBW | ||
| Received Power | -126.011433 | |||
| Link Margin | 18.98856703 | dB |
Table 1 shows the uplink budget during the communication. The analysis is done at 437.5 MHz with satellite antenna gain of 2.2 dBi and Ground Station antenna gain of 12 dBi with the transmission power of 14W for the tele-commands. The link margin thus obtained is 18.9 dB.
Downlink Budget
Nepal-PQ1 Down Link Budget Analysis using SNR Method
Table 2 : Downlink Budget Analysis
| Frequency: | 437.5 | MHz | ||||
| Orbital Altitude | 500 | km | ||||
| Elevation Angle | 35 | Deg | ||||
| Distance: | 815.08896 | km | ||||
| Transmit Power: | 0.1 | W | Pt | |||
| -10 | dBW | |||||
| Spacecraft | Spacecraft Antenna Gain | 2.2 | dBi | |||
| Spacecraft Line Loss | 1 | dB | ||||
| EIRP | -8.8 | Transmit Power-Gain-Loss | ||||
| GFSK(2K00F1D) | CW Morse (500H A1A) | RTTY FSK (515H F1B) | ||||
| Downlink Path | Free Space Path Loss: | 143.47366 | 143.4736614 | 143.4736614 | dB | 32.4+20log(d)+20log(f) |
| Antenna Pointing Loss: | 1 | 1 | 1 | dB | ||
| Antenna Polorization Loss: | 1 | 1 | 1 | dB | ||
| Atmospheric Loss: | 2 | 2 | 2 | dB | ||
| Ionospheric Loss: | 1 | 1 | 1 | dB | ||
| Rain Loss: | 0 | 0 | 0 | dB | ||
| Ground Station | Isotropic Signal Level at GS | -157.2736614 | -157.2736614 | -157.2736614 | dB | EIRP-Losses |
| GS Antenna Pointing Loss | 0.2 | 0.2 | 0.2 | dB | ||
| GS Antenna Gain | 12 | 12 | 12 | dB | ||
| GS Transmission Loss | 2 | 2 | 2 | dB | ||
| Ground Station Effective Noise Temperature: | 635 | 635 | 635 | K | ||
| Ground Station Figure of Merrit (G/T): | -18.22773725 | -18.22773725 | -18.22773725 | dB/K | (=Gain-Losses-Noise temperature) in dB | |
| Signal Power at Input of LNA | -147.4736614 | -147.4736614 | -147.4736614 | dBW | (=Signal Level at GS-Gain-Losses) | |
| Boltzman’s Constant | -228.6 | -228.6 | -228.6 | dbW/K/Hz | ||
| Receiver Bandwidth | 2000 | 500 | 515 | Hz | ||
| Receiver Noise Power | -167.5619628 | -173.5825627 | -173.4541905 | dBW | Pn = K + 10log(Ts) + 10log(B) | |
| SNR at Receiver | 20.08830138 | 26.1089013 | 25.98052905 | dB | Signal Power-Noise Power | |
| Required SNR | 12.8 | 10 | 10 | dB | ||
| Link Margin | 7.288301384 | 16.1089013 | 15.98052905 | dB |
Table 2 shows the downlink budget analysis for the communication. The analysis is done at 437.5 MHz with satellite antenna gain of 2.2 dBi and Ground Station antenna gain of 12 dBi with the transmission power of 100mW. The link margin thus obtained for GFSK, CW Morse and RTTY FSK are 7.2 dB, 16 dB and 15 dB simultaneously.
