AboutLuis Emiliani Expertise Strengths
- Satellite link design and analysis
- Vsat network design and analysis
- Propagation aspects for terrestrial and satellite links
- ITU-R P recommendations
Can not help with:
- Questions related to TV receivers, TV kits, or specific networks such as DirecTV or DISH
- Antenna pattern synthesis, RF MoM analysis, S-parameters.
Experience My experience is in satellite communication networks and terrestrial microwave links.
What is the noise level that the satellite receive antenna
can be tolerated, does it depends on the G/T of the satellite antenna?
Answer Hi,
The G/T or figure of merit of a receive system is a measure of how noisy the receive system is. the T is the equivalent noise temperature in Kelvin. it depends on the noise temperature of each one of the elements of the receive chain, antenna included.
i believe your questio should be rephrased as how much noise a modem tolerates, as the antenna itself does not care. the antenna receives signals and does not discriminate or care about whether those signals are interesting (as in your information) or not (as in thermal, radio or electrical noise)
when you do a link budget you are determining the carrier to noise ratio (C/N). if your link is digital, you translate this C/N into the Eb/No, the ratio of the energy per bit to the noise power density (per hertz). this Eb/No can then be linked to the bit error rate of your link. the amount of additional noise tolerated by your application depends on the maximum bit error rate you can live with. the maximum bit error rate depends in turn on the type of traffic you carry (real time, non real time) and on the error control procedures you have put in place (coding, repeat requests, etc).
so in order to answer this question you need to think also in terms of what services do you provide. traditionally, voice servic3es degrade when the bit error rate is greater than 10 E -3, for data services, a bit rate of 10E-6 is good in the data rate is in the order of hundreds of kilobits, and a bit rate of 10 E-7 or -8 is appropriate for services in the oprder of megabits. the higher the bit rate, the lower the bit error rate needs to be. a bit error rate of 10E-6 means that on average you will see an error every million of bits sent.
