Satellite Broadcasting

Fig. 25:
Outdoor-Indoor-Unit

• Antenna shall be positioned with line of sight to the satellite.
• Antenna shall be mounted on a proper foundation.
• LNB is remotely supplied by RX.
• Cable with a length of up to 50m mechanically protected.
• Be aware of lightning protection.
• Connectors at LNB shall be water-resistant by using shrink or rubber sleeves.

• Satellite Broadcasting operates mainly on C-Band and KU-Band
• Typical Antenna Types are Parabolic Antennas
• On KU-Band also TVRO Panel Antennas (Dipole Arrays) are used
• Efficiency of Antenna is important and depends mainly on surface roughness
• Besides fixed Position Antennas also turning Antennas are used
• Above a certain size/aperture tracking becomes necessary
• Mechanical Stability is a expensive but guarantees long availability
• LNB/Feedhorn/Polariser is normally part of TVRO Antenna (Outdoor Unit)

Fig. 26: Prime-Focus Antenna	Fig. 27: Prime-Focus Antenna

Fig. 28: Offset-Antenna	Fig. 29: Offset-Antenna

Fig. 28: Cassegrain-Antenna	Fig. 29: Cassegrain-Antenna

Fig. 32:
Azimuth and elevation -
Schematic is valid for northern hemisphere

Fig. 33:
Worldmap with timezones, longitude and latitude

• Feedhorn collects microwaves and feeds it into the LNB.
• Polariser is a switch for the incoming wave type and is positioned between Feedhorn and LNB.

Fig. 34:
Feedhorn and Polariser

	Signal from Feedhorn/Polariser
C-Band 3.800-4.200GHz		Ku-Band 10.700-12.750GHz
fRX = fosc - fSAT		fRX = fSAT - fosc

LNB-Practical Layouts and Specs

		Typical Specification: Input Frequency (GHz) L.O. Frequency Output Frequency Noise Figure/Noise Temperature L.O. Stability L.O. Phase Noise Conversion Gain Output Level Power Requirements (H/V) Relation of Noise Temp. and Figure: e.g. 75K = 1dB
Fig. 37: C-Band W 275
Fig. 38: Ku-Band W 75

The Figure of Merit (G/T) depends on:

• size of dish (diameter)
• antenna efficiency ( surface of dish)
• proper mechanical alignment of LNA/LNB.
• LNA/LNB with noise figure (< 1DB) OR NOISE TEMPERATURE (< 75°K)

Reliability and long lifetime are achieved by using heavy duty materials to withstand high windload and aggressive environment.

• Larger dishes need concrete foundation.
• electrical connections outside have to be protected against water and dust.

• Receives and demodulates frequency modulated TV-signals on UHF
• Switchable Bandwidth 16/27/36 MHz
• Selects one TV and up to 9 Radio Channels
• Low price, from 50 US$ onwards
• System price, including dish(60cm) and LNB, from 100 US$ onwards

Fig. 39:
Block diagram of analogue Receiver

• Input Frequency depending on C- or Ku -Band
• LNB - Local Oscillator Frequency
• TV/FM-Bandwidth/FM-Deviaton
• audio channels between 6 and 10 MHz
• RF-bandwidth for mono to video of 280kHz or audio subcarriers of 130kHz
• Deemphasis 50ms, 75ms, J17
• Wegener Panda Decoder for analog audio carriers or digital in case of ADR (Astra Digital Radio)

Fig. 40:
Analogue satellite signal

• IRD (Integrated Receiver Decoder) also called Set Top Box (STB)
• Receives and decodes signals compliant to DVB-MPEG-2 Standard.
• Front-end: Tuner, ADC, Demodulator and FEC for DVB-S, -C, -T.
• Back-end: MPEG-2 TS-demultiplexer, Audio/Video-decoder, Video-encoder.
• Further functions: Audio DAC, controller, graphic&display processor, modem ,
• IRD provides standard output signals via SCART, Cinch or prof. Interfaces
• TV in composite/component video, RF-modulator, SDI (270Mbitps)
• Audio in analogue (un/sym) or digital AES/EBU, SPDIF
• Transport Stream Input/Output (ASI/LVDS)
• DATA Input/Output (RS232/484) for IRD-control, downloads or SW-updates
• High Speed Serial Multimedia Interconnection Bus IEEE 1394

Fig. 41:
IRD Blockdiagram

Fig. 42:
IRD-Chipsets

• Settings to Satellite parameters
  • Satellite receiving frequency (e.g.: 3912 MHz or 3.912 GHz)
  • LNB-Oscillator frequency (e.g.: 5150 MHz for C-Band)
  • Polarisation (e.g.: RHCP (right hand circular polarisation))
  • Symbolrate (e.g.: 8.022 Msymb)
  • Forward Error Correction/FEC (e.g.: 3/4)


• Station search
  • automatic
  • manual


• TV-Standards
  • PAL
  • NTSC
  • Secam


• LNB-Supply

Fig. 43:
IRD - Connections Consumer

5.2 Coverage INTELSAT 707

Fig. 44: Coverage INTELSAT 707 FEC 1/2	Fig. 45: Coverage INTELSAT 707 FEC 3/4

5.3 Coverage AsiaSat 2

Fig. 46:
Coverage AsiaSat 2

5.4 Coverage PAS-5

Fig. 47:
Coverage PAS-5

5.5 Coverage Eutelsat HOTBIRD 5

Fig. 48:
Coverage Eutelsat HOTBIRD 5

5.6 Coverage Astra 1A

Fig. 49:
Coverage Astra 1A

5.7 DW - Eutelsat HB5, NSS-K(IS-K) and GE1

Fig. 50:
DW - Eutelsat HB5, NSS-K(IS-K) and GE1

5.8 DW - Eutelsat HB5, Astra 1A and 1B

Fig. 51:
DW - Eutelsat HB5, Astra 1A and 1B

5.9 DW - Eutelsat HB5 and PAS-5

Fig. 52:
DW - Eutelsat HB5 and PAS-5

5.10 DW - INTELSAT 707 and AsiaSat 2

Fig. 53:
DW - INTELSAT 707 and AsiaSat 2

Sendertechnik:
Tel.: ++49 (0) 221 3893211    FAX: ++49 (0) 221 3893270/99
Arno Selders, selders@dwelle.de
Wilfried Schäfers, schafers@dwelle.de
Hermann Josef Fuchs, fuchs@dwelle.de

Transmission Management:
Tel.: ++49 (0) 221 3893201    FAX: ++49 (0) 221 3893200
Horst Scholz, hscholz@dwelle.de
Norbert Schall, nschall@dwelle.de
Waldemar Krämer, kraemer@dwelle.de

Distribution:
Tel.: ++49 (0) 221 3892782    FAX: ++49 (0) 221 3892784
Dr. Burkhardt Nowotny, nowotny@dwelle.de
Heinz - G. Pianka, hpianka@dwelle.de (Asia)
Peter Stabusch, stabusch@dwelle.de (Afrika)

Satellite Broadcasting