Application and Construction of Coax Cables for 75 Ohm Video Systems

Applications.
CCTV: Closed Circuit Television is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors
SMATV: Satellite Master Antenna Television used to deliver signals to multiple dwelling units (e.g., apartment buildings and trailer parks).
CATV: Central Antenna Television = Cable television is a system of providing television to consumers via radio frequency signals transmitted to televisions. Nowadays also used for internet and telephone.
HDTV: High-definition television refers to video having resolution substantially higher than traditional television systems.
Telecom and networking: a number of special cable constructions.

Basic Cable Design.
Coaxial cables are designed to carry radio frequency current of a much higher frequency than the 50 or 60 Hz used in low voltage cables. And this requires special construction to prevent power losses. If an ordinary wire is used to carry high frequency currents, the wire acts as an antenna, and the high frequency currents radiate off the wire as radio waves, causing power losses. To prevent this, in coaxial cable one of the conductors is formed into a tube and encloses the other conductor. This confines the radio waves from the central conductor to the space inside the tube. To prevent the outer conductor, or shield, from radiating, it is connected to electrical ground, keeping it at a constant potential.
The dimensions and spacing of the conductors must be uniform throughout the length of the cable. Any abrupt change in the spacing of the two conductors along the cable tends to reflect radio frequency power back toward the source. This acts as a bottleneck, reducing the amount of power reaching the destination end of the cable.

Choosing the correct 75 ohm coax cable.
Most coaxial cables for video applications have a nominal impedance of 75 ohms. Their differing electrical and physical characteristics make it important to select the correct type of cable to suit the application.

RG-Type TV-Type Information
RG59 Analogue TV Acceptable performance on cable runs < 225 metres
RG6 Analogue TV Gives superior performance on cable runs < 225 metres.
Used for cable runs > 225 metres but < 545 metres.
RG11 Analogue TV For cable runs greater than 545 metres.
RG59 CCTV Acceptable performance on cable runs < 225 metres
RG6 CCTV Gives superior performance on cable runs < 225 metres.
Used for cable runs > 225 metres but < 545 metres.
RG11 CCTV For cable runs greater than 545 metres.

This table is for reference only.

BT Cables survey of Part Numbers.

Application Tested Speciality RG-59 RG-6 RG-11
CCTV – PVC sheath 1000 MHz Solid conductor C1028 C1029 C1030
CCTV – HFFR sheath 1000 MHz Solid conductor C1428 C1429 C1430
CCTV 1000 MHz Flexible conductor C1275 C1276 C1277
CATV / SMATV 3000 MHz Dual screen C1025 C1026 C1027
CATV / SMATV 3000 MHz Quad screen C1256 C1257 C1241
HDTV – PVC sheath 4500 MHz Dual Screen 95% C1229 C1279 C1280
HDTV – HFFR sheath 4500 MHz Dual Screen 95% C1378 C1379 C1380

Operating temperature range: -25 to +75 °C and Rated Voltage: 300 Vrms

CCTV and Video Applications, sweep tested 1to 1000 MHz

CABLE DESCRIPTION

  1. Conductor Solid or Flexible Bare Copper
  2. Dielectric Foamed Polyethylene (FPE)
  3. Braid Bare Copper
  4. Sheath Material Polyvinyl Chloride (PVC) or Halogen-Free (HFFR)

Standard Put Up Length 3 305 or 500 metres

Standard References IEC 61196 (BS) EN 50117 (BS) EN 50290-2 IEC 60332-1 (PVC sheath) or IEC 60332-3-24 (HFFR cable) IEC 61034 (only HFFR cable) IEC 60754-1 & 2 (HFFR cable) RoHS directives

Physical Characteristics

BT Cables Part Number RG-Type Conductor (mm) Diameter Dielectric (mm) Coverage braid (%) Sheath Material Overall Diameter (mm) Weight (kg/km)
C1028 RG-59 0.81 solid 3.71 95 PVC 6.0 47.12
C1428 RG-59 0.81 solid 3.71 95 HFFR 6.0 48.5
C1275 RG-59 19x0.18TC 3.71 95 PVC 6.0 47.12
C1029 RG-6 1.02 solid 4.60 95 PVC 6.8 55.5
C1429 RG-6 1.02 solid 4.60 95 HFFR 6.8 58.2
C1276 RG-6 19x0.22 4.60 95 PVC 6.8 54.66
C1030 RG-11 1.63 solid 7.11 90 PVC 10.0 115.9
C1480 RG-11 1.63 solid 7.11 90 HFFR 10.0 120
C1277 RG-11 19x0.34 7.11 90 PVC 10.0 115.9

Electrical and Physical Characteristics (at 20°C)

BT Cables Part Number RG-Type Impedance (O) Max. DC Resistance Conductor (O/km) Max. DC Resistance screen (O/km) Nominal Capacitance (pF/m) Min. Return Loss 1 to 1000 MHZ (dB)
C1028 RG-59 75 ± 3 33.5 10.1 53.5 20
C1428 RG-59 75 ± 3 33.5 10.1 53.5 20
C1275 RG-59 075 ± 3 40 10.1 53.5 20
C1029 RG-6 75 ± 3 21.5 10.8 53.5 20
C1029 RG-6 75 ± 3 21.5 10.8 53.5 20
C1429 RG-6 75 ± 3 30 10.8 53.5 20
C1030 RG-11 75 ± 3 8.8 6.5 52.8 20
C1480 RG-11 75 ± 3 8.8 6.5 52.8 20
C1277 RG-11 75 ± 3 8.8 6.5 52.8 20

Nominal Attenuation in dB/100m

MHz 5 10 50 100 200 300 400 450 550 700 750 870 1000
RG-59 1.9 2.95 6.23 8.53 11.81 15.3 16.41 18.92 21.03 22.97 24.8 26.84 27.89
RG-6 1.78 2.36 4.92 6.56 9.51 12.43 13.78 15.14 17.15 18.37 19.73 20.26 21.96
RG-11 0.99 1.51 2.96 4.27 6.23 8.27 9.51 10.31 11.51 13.45 13.95 14.87 17.06

For more details, please see the respective detailed datasheet(s).

SMATV - CATV and Video applications, sweep tested1to 3000 MHz

CABLE DESCRIPTION

  1. Conductor Solid Copper Covered Steel (CCS)
  2. Dielectric Foamed Polyethylene (FPE)
  3. Screen 1 Bonded Aluminium/Polyester foil 100% coverage
  4. Braid 1 Aluminium
  5. Braid 2 (Quad scrn only) Aluminium/Polyester foil 100% coverage
  6. Screen 2 (Quad scrn only) Aluminium
  7. Sheath Polyvinyl Chloride (PVC)

Standard Put Up Length 305 or 500 metres

Standard References IEC 61196 (BS) EN 50117 (BS) EN 50290-2 IEC 60332-1 RoHS directives

Physical Characteristics

BT Cables Part Number RG-Type Conductor (mm) Diameter Dielectric (mm) Type of Screen Coverage braid (%) Sheath Material Overall Diameter (mm) Weight (kg/km)
C1025 RG-59-3 GHz 0.81 3.71 Dual scrn 54 PVC 6.0 32.42
C1256 RG-59-3 GHz 0.81 3.71 Quad scrn 54 + 46 PVC 6.73 39.4
C1026 RG-6-3 GHz 1.02 4.60 Dual scrn 60 PVC 6.8 41.32
C1257 RG-6-3 GHz 1.02 4.60 Quad scrn 60 + 40 PVC 7.52 49.5
C1027 RG-11-3 GHz 1.63 7.11 Dual scrn 61 PVC 10.0 86.6
C1241 RG-11-3 GHz 1.63 7.11 Quad scrn 60 +40 PVC 10.3 90.6

Dual Screen = Screen 1 + Braid 1
Quad Screen = Screen 1 + Braid 1 + Screen 2 + Braid 2

Electrical and Physical Characteristics (at 20°C)

BT Cables Part Number RG-Type Imped. (O) Max. DC Resistance Conductor (O/km) Max. DC Resistance Screen (O/km) Nominal Capacitance < 1000 MHz* < 2000 MHz* < 3000 MHz*
C1025 RG-59-3 GHz 75 ± 3 146.5 52 53 20 18 16
C1256 RG-59-3 GHz 75 ± 3 146.5 26 53 20 20 20
C1026 RG-6-3 GHz 75 ± 3 92.2 30 53 20 20 20
C1257 RG-6-3 GHz 75 ± 3 92.2 17 53 20 20 20
C1027 RG-11-3 GHz 75 ± 3 36.5 25 53 20 20 20
C1241 RG-11-3 GHz 75 ± 3 36.5 12 53 20 20 20

* Min. Return Loss (dB)

Nominal Attenuation in dB/100m

MHz 5 10 50 100 200 400 550 870 1250 1750 2150 2500 3000
RG-59 2.92 3.45 5.40 8.21 12.56 16.01 19.36 24.74 30.62 36.71 40.82 44.72 48.64
RG-6 2.2 2.48 5.15 6.6 13.12 13.12 15.45 19.69 24.25 29.26 32.88 35.88 39.83
RG-11 1.25 2.03 3.75 5.01 7.05 7.05 9.65 12.6 16.66 20.28 22.93 25.12 28.08

For more details, please see the respective detailed datasheet(s)

HDTV and HD Video applications, sweep tested1to 4500 MHz

CABLE DESCRIPTION

  1. Conductor Solid Bare Copper
  2. Dielectric Foamed Polyethylene
  3. Screen Bonded Aluminium/Polyester foil 100% coverage
  4. Braid Tinned Copper
  5. Sheath Material Polyvinyl Chloride (PVC) or Halogen-free (HFFR) Colour: Orange

Standard Put Up Length 305 or 500 metres

Standard References IEC 61196 (BS) EN 50117 (BS) EN 50290-2 IEC 60332-1(PVC sheath) or IEC 60332-3C ( HFFR cable) IEC 61034 (HFFR cable) IEC 60754-1 & 2 (HFFR cable) RoHS directive

Physical Characteristics

BT Cables Part Number RG-Type Conductor (mm) Diameter Dielectric (mm) Coverage braid (%) Sheath Material Overall Diameter (mm) Weight (kg/km)
C1229 RG-59-4.5 GHz 0.81 solid 3.71 95 PVC 6.0 46.72
c1378 RG-59-4.5 GHz 0.81 solid 3.71 95 HFFR 6.0 48.2
C1279 RG-6-4.5 GHz 19x0.18TC 4.60 95 PVC 6.8 56.2
c1379 RG-6-4.5 GHz 1.02 solid 4.60 95 HFFR 6.8 59
C1280 RG-11-4.5 GHz 1.02 solid 7.11 95 PVC 10.0 114.5
C1380 RG-11-4.5 GHz 19x0.22 7.11 95 HFFR 10.0 117

Electrical and Physical Characteristics (at 20°C)

BT Cables Part Number RG-Type Imped. (O) Max. DC Resistance Conductor (O/km) Max. DC Resistance Screen (O/km) Nominal Capacitance < 1000 MHz* < 2000 MHz* < 3000 MHz* < 4500 MHz*
C1229 RG-59-4.5 GHz 75 ± 3 33.5 12.5 53 23 22 16 15
c1378 RG-59-4.5 GHz 75 ± 3 33.5 12.5 53 23 22 16 15
C1279 RG-6-4.5 GHz 75 ± 3 21.5 10.6 53 23 22 16 15
c1379 RG-6-4.5 GHz 75 ± 3 21.5 10.6 53 23 22 16 15
C1280 RG-11-4.5 GHz 75 ± 3 8.8 6.6 53 23 22 16 15
C1380 RG-11-4.5 GHz 75 ± 3 8.8 6.6 53 23 22 16 15

* Min. Return Loss (dB)

Nominal Attenuation in dB/100m

MHz 1 5 10 50 100 300 550 750 1000 2000 3000 4500
RG-59 0.98 2.07 2.95 6.23 7.55 13.68 18.83 22.23 25.96 38.24 46.13 56.50
RG-6 0.79 1.71 2.33 4.57 6.40 11.96 15.76 18.05 21.36 31.44 39.76 50.46
RG-11 0.53 1.12 1.51 2.96 12.56 7.49 10.41 12.38 14.57 21.84 27.93 35.98

For more details, please see the respective detailed datasheet(s)

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