Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 1)Draw the general block diagram of satellite link. SHAPE \* MERGEFORMAT
|
Satellite |
|
User |
|
Terrestrial system |
|
Earth Station |
|
User |
|
Terrestrial system |
|
Earth Station
|
2)Frequency bands used in satellite link.
|
BAND |
DOWNLINK(MHz) |
UPLINK(MHz) |
|
UHF-military |
250-270 |
292-312 |
|
C band- commercial |
3700-4200 |
5925-6425 |
|
X band- military |
7250-7750 |
7900-8400 |
|
Ku band-commercial |
11700-12200 |
14000-14500 |
|
Ka band- commercial |
17700-21200 |
27500-30000 |
|
Ka band- military |
20200-21200 |
43500-45500 |
3) Frequency bands used for satellite link in the lab usually?
S band= 2 to 4 GHz
4)What types of antennas used for earth stations and transponder for satellite link?
- For earth station, paraboloid antenna with focal point feed and cassegrain antenna. Also horn and phased array antenna can be used.
- For transponder, dual reflector antenna and microstrip antenna will be used.
5)What type of antenna is used in the lab usually?
Helical antenna
6)Explain C/N ratio of a satellite link?
C/N = EIRP + Gt -Lp-N
Where, EIRP- Effective Isolated Radiated Pattern of the antenna
Gt – Gain of the antenna
Lp- Path Loss
N- noise
7)Why uplink frequency greater than downlink frequency?
Because the uplink frequency is processed at the earth station, where power consumption is not a big deal. Whereas in satellite the power consumption is a important parameter, since the power is generated by the solar cells.
8)What is the uplink frequency of C band and Ku band and downlink frequency of C band and Ku band?.
C band: uplink- 6 GHz ad down link – 4GHz
Ku band: uplink – 14 GHz and downlink – 12 GHz
9) What is the use of satellite link?
- The coverage area of a satellite greatly exceeds that of a terrestrial system.
- Transmission cost of a satellite is independent of the distance from the center of the coverage area.
- Satellite to Satellite communication is very precise.
- Higher Bandwidths are available for use.
10) Who launched the first satellite? When?
- Soviet sat sputnik, October 4,1957, soviet scientist.
- Sputnik II, November 1957