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.
Expert: Luis Emiliani Date: 6/8/2008 Subject: Dish antenna
Question Dear sir
we are trying to receive the signals from a DSNG van for live feed the satellite details are as follows
Insat 2E at 83.0°E
EIRP(dBW ) 36
the DSNG van Upink Frequency is 3658 and
Symbol rate is 1700
Signal uplink strength is 80 to 100 watts
what should be the size of the Dish Antenna ?
what LNB Should we use to receive this signal?
what receiver should we use?
Answer Hi,
what you need to do is to perform the full link budget for the carrier you intend to transmit
in addition to what you already know, you need to find out:
1. satellite details: saturation flux density, G/T in the direction of the transmitter, EIRP in the direction of the receiving end, transponder bandwidth, input backoff, output backoff of the transponder to use, frequency plan of the transponder to use.
2. carrier and service parameters
modulation (you already have an idea as you have the symbol rate), roll-off factor of the filters in the transmitter and receiver
3. your location
latitude, longitude and elevation
you then input all the data you know plus the data you need to find out and solve the link equation for the carrier profile (you use DVB-DSNG, i assume you are working in QPSK with 3/4 FEC, but please verify this) and make sure you are above say 6 dB of receive Eb/No plus any margin for propagation impairments. a received Eb/No of 10 dB in clear sky should be good.
the LNB depends on the frequency band you are working in, C, Ku, Ku high, Ku low...i can not say which one without knowing all the details. All i can say at the time is that you are looking at a C band Lnb...At that symbol rate perhaps a DRO could be enough, but in doubt always go for a PLL. look for a noise figure around 0.8 dB for a good one. they cost around 250 dollars.
i am sorry i can not be of much assistance, but you need more information to solve your question.
there are some websites giving online link calculations, you might want to google for those.#
also, check the satellite operator's website for the data for your particular satellite, or check lyngsat, they might have them for you.
