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LinkBudget:
FIXME FIXME
%%\[ \frac{C}{N_0} = EIRP - Losses + (G/T) - k - B = 7.8 dB\] %B=12kHz
%\[ \frac{C}{N_0} = EIRP - Losses + (G/T) - k - B = 3.6 dB\] %B=20kHz
%%\[ \frac{C}{N_0} = EIRP - Losses + (G/T) - k - B = -3.3 dB\] %B=40kHz
%\hspace{9cm}(optimistic !!)
%%\[ \frac{C}{N_0} + B = -3 +4 -(1 + 135 + 0.6 + 3) + 6 -(-222) -81.5 = 7.8 dB \]
%%\[ \frac{C}{N_0} = 7.8 dB \]
%\begin{description}[xxxxxxxxxxxxxxxxx]
%\item[TxPower] $0.5W = -3 dBW$
%\item[Rx G/T] $6dB$
%\item[AntennaGain] $4 dBi$ ($~65\% $ of time)
%\item[FSPL] $310km$,$434Mhz$ $\rightarrow 135dB$ % $-20log_{10}(310km) -20log_{10}(434Mhz)-32.45 = -135 dB$
%\item[Sky Thermal Noise] $4^o C \rightarrow -222dBJ/K$ % $k=10 log_{10}(kTB) = -222dBJ/K$ (at $4\angle C, 1 Hz N_0$) %noise at normalized bandwith = 1 Hz
%%\item[Bandwidth] $B=12KHz=81.5dBHz$ %$B=20*log10( 12kHz [Hz]) = 81.5 [dBHz]$
%\item[Bandwidth] $B=20KHz=86dBHz$
%%\item[Bandwidth] $B=40KHz=92dBHz$
%\item[$L\rightarrow C$ polarisation] $-3dB$
$\frac{C}{N_0}=EIRP - Losses + (G/T) - k - B $
70cm: %\[ \frac{C}{N_0} + B = -3 +4 -(1 + 135 + 0.6 + 3) + 6 -(-222) -81.5 = 7.8 dB \]
downlink 70cm: $\frac{C}{T}= (10*math.log(0.5,10) + 8.3) - (1 + 135 + 0.6 + 3 ) + 6 - 81.5 = -209.8 dB$
k=-228.6 dB (J/K) -> 1K
Noise: $N=N_0 B=k T B$
Carrier Power: $C=\frac{P}{4 \pi R^2} G_r A_{eff}
Antenna Gain: $\roh \frac{\pi^2 D^2}{\lambda^2}$:
$EIRP = P_T * G_T$
Free Space Loss: \lbracket\frac{4 \pi R}{\lambda}\rbracket^2
$\frac{E_b}{N_0}=\frac{C}{N}\frac{B}{r}
Transmission Power: 10 log10( [W])
Antennagain Sat:
wavelength: 2m / 70cm
antenna length: ~0.5m (wenn nicht faltbar ~0.25m)
(2m/0.5m = 1/4 -> gain: ~ 2 dBi)
2m/0.25 = 1/8 -> gain: < 2 dBi
(0.7m/0.5m = 1.5 -> gain: 3.01 dBi)
0.7m/0.25m = 3 -> gain: 4.47 dBi
aktuell: 2m: 2dBi 70cm: 4.4dBi
Antennagain Boden:
Gain: 6 dBd / 8.3 dbi
G/T: 8.3 - 1 + 25 - 4 - NoiseTemp = 8.3 - 2 = 6
Loss:
Alignment-Loss: 0,2..1dB
FreeSpaceLoss (AntennaAparture + spreading of radiated power) = 20*log10(d [km]) + 20*log10(f [Mhz]) + 32.45 =
2m: 82.3dB + 43dB = 125dB
70cm: 82.3dB + 52.7dB = 135dB
Atmosphärendämpfung: <1dB (0.6dB)
Polarisation Linear(send) auf Circular(Empfang): 3dB
Bandbreite: 20*log10( 12kHz [Hz]) = 81.5 [dBHz]
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