Kathrein MSK 125 manual Technical Appendix, SIGNAL-TO-NOISE Ratio, +14.1 dB

TECHNICAL APPENDIX

SIGNAL-TO-NOISE RATIO

To determine the carrier-to-noise-ratio (C/N) for analogue transponders, the following values must be known:

•Ambient noise level (adjust parabolic antenna so that no satellite signal is received)

•max. reception signal

•Bandwidth correction

The following formula applies:

C/N = reception signal level - ambient noise level - bandwidth correction

(MSK 125 measurement bandwidth) 6 MHz Bandwidth correction value = 10 log ––––––––––––––––––––––––––––––––––

RF bandwidth reception signal Bandwidth correction value = 6.37 dB for 26 MHz bandwidth (Astra)

Bandwidth correction value = 7.78 dB for 36 MHz (Eutelsat, Intelsat,

Kopernikus)

Example

Reception signal level	+75.5 dB	with satellite signal
Ambient noise level	-55.0 dB	without satellite signal
Carrier-to-noise (C/N) ratio	+20.5 dB
Bandwidth correction	-6.4 dB	for 26 MHz bandwidth
C/N of receiver	+14.1 dB

Note

For exact C/N determination it is essential that the RF bandwidth of the reception signal is considered.

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