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Microwave Transmission (Telecom (Wireless and Antenna Applications), Military, Test & Measurement, and Aerospace)

Microwave Transmission (Telecom (Wireless and Antenna Applications), Military, Test & Measurement, and Aerospace)

Contents

1. Introduction
    1.1. Benefits of standardization
2. Telecom (Wireless and Antenna Applications)
    2.1. Antenna Feeder Cable
           2.1.1. Example of a feeder cable
    2.2. Examples of Telecom RF Cables from Andrew, Gore
    2.3. Andrew Wireless Cables
3. Military Cables
    3.1. Gore Microwave Cable for Military application
    3.2. Internally Ruggedized Microwave / RF Coaxial Assemblies
    3.3. Size 8 and 12 Contact Microwave/RF cable Assembly
4. Test & Measurement Cable
    4.1. Example of Gore Microwave / RF Cable for Test Applications
5. Aerospace cable
    5.1. Example of Microwave/RF Cable Assemblies for Aircraft Applications from Gore
    5.2. Space flight Microwave/RF Assemblies from Gore
6. LAN cable
7. Data Cable
8. Instrumentation Cable
9. Submarine Cable
    9.1. Example of Submarine coaxial cable
10. Annexure
 

1. Introduction

Microwave cables fall into a category of cables that operate in the frequency band of operation in the microwave and millimetre range (upto 110 GHz). The applications include point-to-point microwave links, point to multipoint radio communication, satellite and wireless services such as WiFi, WiMAX etc.

These applications are prevalent in key sectors such as defense, scientific, space, aviation, medical and commercial sectors. The nature of these applications demand special focus on the cable construction, assembly, mechanical and electrical parameters. These parameters, which are specific to a particular application, are well documented in the form of standards and specifications published by a plethora of organizations (Annexure A). There is a multitude of specs and standards published by organizations (both governmental and private), which define the course of product development in the area of cable and wire.

1.1. Benefits of standardization

Standards make positive impact to our society by assuring us about the desirable characteristics of products and services such as quality, environmental friendliness, sayfety, reliability, efficiency and interoperability - and at an economical cost. Under the aegis of standardization, all the stakeholders in a particular industry agree on specifications and criteria to be applied consistently in the classification of materials, in the manufacture and supply of products, in testing and analysis, in terminology and in the provision of services. In short, the standards provide a reference framework that speaks a common technological language between the producers and the consumers. Regional standardization (American, European, Japanese to name a few) in certain economic zones and geographies at times collaborates with the international standardization process, which enables growth and innovation at a global scale.

To summarize, international standardization has the following benefits:

  • Efficient, safer and cleaner ways to develop, manufacture and supply of products and services to consumers
  • Enable fair trade between countries
  • Share and disseminate good practices, information and ideas
  • Platform to verify conformity, assessment and legislation

In cable industry the widely used standards are military standards or the MIL standards, which are followed across the industries. Over and above the military standards there are international standards such as ISO/IEC and regional standards adding different flavour and types to the cable standards. Annexure A lists some of these widely referred to standards.

2. Telecom (Wireless and Antenna Applications)

Cable manufacturers offer a broad array of telecom cable products designed to increase the reliability of telecommunications systems. Telecom cables are used in both indoor and outdoor applications such as point-to-point microwave links, Wireless LAN network, WiFi/WiMAX and LMDS links. The cable products are found in applications such as:

  • Switching systems,
  • Terabit routers
  • Wireless handsets wireless base station infrastructure components
  • High speed and fidelity cables provide broadband signal transmissions
  • EMI Shielding for isolating RF and digital signals o Protective Vents, and cooling Filters provide electronic components, base station cabinets, and hand-held devices protection from heat, pressure, and environmental contaminants such as dirt, water and corrosive agents.
  • Base station jumpers and antenna cable

2.1. Antenna Feeder Cable

This cable uses low loss polyethylene foam, which has very low dielectric losses resulting in low insertion loss. The feeder cable connects the output of a radio transmitter (usually installed in an indoor environment) to the antenna port connector, which is mounted on a tower (installed in an outdoor environment). Typically these cable are 50-ohm impedance, operate upto 20 GHz with shielding effectiveness of better than 120 dB, insertion loss of 0.33 dB/ft at 20 GHz and with peak power rating of 0.3 KW at 1 GHz.

2.1.1. Example of a feeder cable

Feeder Cable Developed for microwave, satellite and cell phone communication masts, these cables are manufactured to ensure optimum performance. Available for outdoors, flame retardant and Low Smoke Halogen Free jackets to meet all needs.

 

2.2. Examples of Telecom RF Cables from Andrew, Gore

Manufacturer like Commscope/Andrew (www.commscope.com) design and manufacture a wide range of telecommunication coaxial cables and waveguide systems (including cables used with antennas) used for semi-flexible RF transmission line solution in land mobile, broadcast, cellular, PCS, military, terrestrial microwave, HF, earth station, personal communication, and many other applications. Some of these cables are listed here.

Braided Cable  Radiating Cable
Braided Cable Radiating Cable
Braided cables are useful for applications such as mobile phones, in-building, unlicensed band, mobile antennas, satellite antennas, terrestrial microwave, Wi-Fi, Broadband, medical, military, air traffic control, automotive, land mobile radio, local multipoint distribution system, multichannel multipoint distribution service, wireless local loop, personal communication system, mobile, in-building, and fixed wireless networks. RADIAX® radiating coaxial cables are used for wireless communication in confined areas by functioning as a continuous distributed antenna. The cable has controlled slots in the outer conductor, which allow RF signals to be coupled from and into the cable uniformly along the entire length. These cables are optimised for specific frequency bands for single or dual-band RF systems or for frequency bands from 50 MHz to 2.4 GHz or Plenum rated for fire retardant cables. These cables are assembled with Type N and 7-16 DIN connectors.

 2.3. Andrew Wireless Cables

Andrew Solutions offers a wide variety of cable types and sizes including corrugated cables for wireless network operators. These are low-loss closed cell foam cables. The cable uses solid triple-bonded construction with foam center filling for weather resistance, crush and tensile strength, and is better than the corrugated cables. They are useful in difficult installations without cable stretching.  

HELIAX® 2.0 Cable HELIAX® AVA Cable HELIAX® Air Dielectric Coaxial Cable
Heliax 2.0 Cable Heliax AVA Cable Heliax Di-electric Cable
HELIAX® series is a type of coaxial cable known as hard line cable. HELIAX® 2.0 cable is a 50 ohm cable designed with smooth wall and corrugated technologies for easy installation and RF performance. These cables are specially designed keeping system budget and cost in mind and in wireless applications such as connecting tall towers. This cable is useful for site installations. These are low VSWR cables used for antenna connection. It provides a pressure path to pressurizable microwave antenna feeds and are used as a feeder cable for antennas with air dielectric feeds for 2.7 GHz and below. Available in different sizes: 7/8", 1-5/8" and 2-1/4" and with connector and frequency options.

3. Military Cables

Cable carrying electrical signal such as RF, power or control signal for military application fall into the category of military cable. Military cables such as the RG cables are extensively used telecommunication applications. The military has contributed to the cable industry evolution and its set of standards and products have propelled the telecom industry since WWII. Cable manufacturers and standards organization have referred to the military standards and their products have equivalent military part numbers. For example the military grade RG series cables have equivalent products in the industrial and commercial industry.

The military cable is designed and manufactured as per a set of guidelines called the MIL-standards and specifications. The interpretation of the various military specifications and standards is as follows:

MIL-C: specs for coaxial cable
MIL-W: specs for wire
MIL-DTL: Detail specification
MIL-PRF: Performance specification
MIL-Handbook: overall specification of a product

In general, a military cable has many more stringent requirements than a commercial grade cable. These requirements are over and above the normal set of electrical, mechanical and performance requirements. Some of the key reasons contributing to these requirements are generalized below:

  • High temperature, humidity, salinity
  • High wind velocity, stormy or hostile condition
  • Resistant to abrasive and corrosive forces
  • High Tensile strength and cable pulling
  • Shielding from RFI
  • Shielding for RF leakage
  • Water proof and rugged
  • Vibration tolerant
  • 100% reliable

In the following table a list some of RF cable descriptions are mapped to the corresponding military specifications used in various applications.

Applicable Specs Military category cable description
MIL-W-76B Type MW These cables have the following properties
  • Tinned copper center conductor
  • Plenum grade, PVC insulation
  • Temperature range: -12°C to +90°C
  • Used for Internal wiring of electrical and electronic equipment, Internal wiring of panels and meters, Point-to-point wiring.
MIL-W-16878/1 & /2 (Type B & C) These cables have the following properties:
  • Stranded tinned copper center conductor
  • PVC insulation
  • Temperature Range: -55°C to +105°C
  • Voltage Rating: 600 Volts
  • Used for Military harnessing, power supply lead wire, appliance wiring, and medical electronic devices
MIL-W-16878/4 Type E These cables have:
  • Silver plated copper inner conductor
  • PTFE insulation
  • -55°C to +200°C
  • Voltage Rating: 600 Volts
  • Point-to-point wiring of electronic equipment where temperatures up to 200ºC are required.
MIL-W-16878/5 Type EE Over and above Type E cables, these cables have:
  • 60°C to +200°C
  • Voltage Rating: 1000 Volts
  • Used in protected high temperature applications. The MIL Spec wire is resistant to thermal aging, solder iron damage, flame, and moisture. PTFE also resists solvents, greases, ozone and most other chemicals. They are easy to install due to their small size and slippery surface. PTFE has stable electrical characteristics with low power loss, making it ideal for high frequency applications.
MIL-W-16878/6 Type ET High temperature cable:
  • -55°C to +200°C (Silver plated copper conductor)
  • -55°C to +260°C (Nickel plated copper conductor)
MIL-W-22759/7 These cables have:
  • Extruded Teflon® PTFE , reinforced with abrasion resistant mineral fillers , some part numbers have extremely thick insulation sidewalls.
  • Temperature Rating:-55º C to +200º C
  • Voltage Rating: 600 Volts r.m.s
MIL-W-22759/10
  • Nickel plated stranded copper conductor
  • Temperature Rating:-55º C to +260º C
  • Operating Voltage: 1000 Volts
  • This type of MIL-Spec Wire may be used in aerospace applications or any application where high temperatures, smoke emission and flammability are a concern.

        

3.1. Gore Microwave Cable for Military application

In this section we discuss some of the popular brand of cables used in military applications. One such brand is Gore, which is presented here.

1.2 mm Diameter Flexible Microwave cable 2.16 mm Diameter Flexible Microwave / RF Coaxial Assemblies
1.2mm Microwave Cable 2.16 mm Microwave Cable
These cable Assemblies provide a typical attenuation of 5 dB for a meter long cable assembly at 18 GHz. This is suitable for space and airborne applications because of its low weight. This microwave coaxial cable is useful for space, air, and ground applications.

 

Features and Benefits
  • Lightweight (10.0 grams/m nominal)
  • Small minimum bend radius (6.3 mm.)
  • Flexibility for tight routing situations
  • The cable employs a helically wrapped foil as per Mil-Std-1344 providing a Shielding effectiveness of better than 90 dB/ft through 18 GHz.

Features and Benefits
  • Flexibility for tight routing situations
  • Phase variation of 800 PPM from 65°C through +100°C
  • Employs a helically wrapped foil as per Mil-Std-1344 providing a Shielding effectiveness of better than 90 dB/ft through 18 GHz.
  • Stranded center conductor suitable for low-torque requirements

 

3.2. Internally Ruggedized Microwave / RF Coaxial Assemblies

These cables are useful for temperature chamber feed-through, airframe, and general-purpose test applications.

Ruggedized Microwave Cable Features and Benefits
  • Flexible. Available in 50 and 75 Ω impedance.
  • IL = 1.4 dB/m at 26.5 GHz
  • Insertion phase and amplitude stability through 26.5 GHz
  • Crush resistance greater than 45 kg per cm as per MIL-T-81490
  • Torque and kink-resistant offers reliability
  • Useful for thermal vacuum applications from -55°C to +125°C "
  • Abrasion-resistant jacket as per MIL-T-81490

3.3. Size 8 and 12 Contact Microwave/RF cable Assembly

These cables are uniquely designed to have special Size 12 and 8 RF Contacts, which are useful for radar, airborne mission systems and satellite telemetry applications. They are compatible with aircraft and space-qualified cables.

Microwave / RF Cable Assembly with Size 12 Contact Microwave / RF Cable Assembly with Size 8 Contact
Microwave Cable with size12 contact Microwave Cable with size8 contact
Product Features
  • Compatible with MIL-C-D38999/ DIN/ARINC (Aeronautical Radio Incorporated) connector system
  • Spring-loaded contact
  • Improved additive phase noise performance
  • RF leakage as per MIL-STD-1344
Electrical Characteristics:
  • Operating Frequency: DC to 40 GHz
  • Contact Resistance: 0.004 Ω
Electrical Characteristics: 
  • Operating Frequency: DC to 26.5 GHz 
  • Contact Resistance: 0.002 Ω
  • VSWR: 1.20:1 as per MIL-C-39012
  • Insulation Resistance: 100 Mega Ω
  • RF leakage -80 dB min at 18GHz in MIL-C-D38999 connector system
The environmental characteristics (such as thermal shock, salinity, vibration) of the cable conform to MIL-STD-202.

4. Test & Measurement Cable

Test and measurement equipment uses a type of RF and microwave cable, which is used mostly in controlled laboratory environments in a repeatable fashion. Their electrical and mechanical properties are expected to remain constant over a long measurement cycles and over the usage of the T&M equipment. Usually, the T&M vendor supplies these types of cables along with the equipment. General characteristics of these types of cables include the following features:

  • Precision construction of the cable and the connector
  • Durability
  • High performance
  • Phase stability over a wide range of frequency
  • Stable electrical properties such as low insertion loss and good return loss

One of the T&M cable manufacturers is Gore (www.gore.com), which manufactures cable assemblies with excellent insertion phase and amplitude stability used for measurement applications with equipments such as VNA (vector network analyzer). These cables are extremely flexible yet provide acceptable crush, torque and kink resistance. The cable performs over wide operating temperature range, suitable for today's testing requirements.

In addition, there is a category of cable used in EMC laboratory applications. These cable exhibit

  • Ultra low loss 2 dB/m at 40 GHz
  • Rugged crush resistant armoured design
  • DC - 40 GHz
  • Precision airline connector or plug connector with gasket to prevent RF leakage (shielding effectiveness better than 110 dB)
  • Phase matched, time delay of 4 ns/m
  • Solid silver plated copper inner conductor
  • Silver plated copper braid as outer conductor
  • Operating temp - 55 to + 135 degrees C

4.1. Example of Gore Microwave / RF Cable for Test Applications

These cables are used for Vector Network Analyzer equipments as high performance test cables. These cables feature excellent insertion phase and amplitude stability with flexure. At the same time it has environmental protection system featuring extreme crush, torque, and kink resistance. The wide operating temperature range, thermo-vac compatibility, and superior flex life are suitable for test environments.

PHASEFLEX® Microwave/RF Test Cable Assemblies Description
Phaseflex Microwave Cable GORE® PHASEFLEX® Microwave Test cables are designed for phase and amplitude stability for test applications. It uses expanded PTFE dielectric and an environmental protection system providing durability, flexibility, crush and torque resistance and light weight.
Frequency options:
DC to 18 GHz
DC to 26.5 GHz
DC to 40 GHz
DC to 50 GHz
DC to 67 GHz
DC to 110 GHz

Typical Applications
  • Production testing
  • Antenna range
  • Thermal vacuum chambers
  • Remote Device Under Test
  • EMC Test Labs
Features and Benefits
  • Phase and amplitude stability for longer calibration intervals and measurement repeatability
  • Crush, torque, and kink resistance for longer service life and reliability
  • Environmental protection fluid, dust, and dirt, extending service life
  • Phase matching options for parallel or comparative measurements
  • Flexibility for easy usage
  • Replaceable interface options and field serviceable

 


5. Aerospace cable

Aeronautical, aircraft, aviation, space constitute a category, which is popularly referred to as Aerospace application. The cable design and manufacturing processes for airborne applications, broadly needs to take care of the following

  • High forces of acceleration (4 to 6G acceleration in fighter jets!)
  • Shielding from RFI
  • Shielding for RF leakage or emission
  • Withstand shock and vibration
  • Lightweight
  • High reliability

Aerospace cables, which are designed as per the MIL-C specs, are typically designated as "MIL-C-27500A20MD5F02". The following table explains this code.

A Identification method used
20 AWG number of the center conductor used
MD Type of insulation (dielectric material) used
5 Total number of conductors in the cable
F Describes the shielding method applied
02 Describes the jacket style

MIL Specs for Aerospace cable assemblies applies to each of its constituents: the raw cable, the inner conductor and the connector. These are mentioned in brief.

Name of the application Standard Description
 Aerospace Cable  MIL-C-27500 Special features
  • Multiconductor cable with quick disconnect
  • Shock and strain resistant
  • Uses MIL grade wires and connectors

 

Similarly, the MIL spec applicable to the inner conductor is mentioned as follows.

Name of the application Standard Description
 Aerospace Wire or inner conductor (non-hazardous) MIL-W-81044/5 The aerospace cable uses special types of wires as inner conductors 
  • Silver coated copper conductor 
  • Extruded XL Polyalkene insulation 
  • Extruded XL Polyvinylidene Fluoride jacket 
  • 150 degrees C 
  • 600 Volt rating
Aerospace Wire or inner conductor (hazardous) MIL-W-5086 This spec is followed for the inner conductor in hazardous conditions: 
  • The wires are high heat and abrasion resistant 
  • Compounded PVC insulation 
  • Impregnated glass braid with nylon coating shield
  • The inner conductor is made of stranded tinned copper.

The most common type of connector used in an aerospace cable assembly is the Circular connector. The circular connectors used in an aerospace cable assembly has the following features

  • They are multi conductor connector
  • Available in multiple mating and locking mechanism such as threaded, push-pull, cam-lock and breach-lock
  • Crimp or solder options.
  • O-rings as sealant for anti- moisture and corrosion
  • Hermetically sealed to withstand high pressure and vacuum.

MIL specs that are applicable to the connectors are:

Name of the application Standard Description
Aerospace Connectors MIL-C-1505

 

Circular connector, with the following features: 
  • Withstand high voltage upto 7000 Volts 
  • Large cable and wire sizes 
  • Withstand shock, high and low temperatures 
  • Immersion resistant 
  • Multiple connect and disconnect cycles 
  • Pressurized connector
  MIL-C-38999 These connectors are meant to carry small signal and voltages. They use smaller gauge inner conductors.

5.1. Example of Microwave/RF Cable Assemblies for Aircraft Applications from Gore

This cable is useful for Airframe microwave interconnect requirement and designed to meet the stringent specification requirements of the military and commercial aircraft.

Microwave Cable for Aircraft Key Features
  • Durable Vapour Sealing as per MIL-T-81490, useful in harsh environments
  • Crushproof Design as per MIL-T-81490
  • High Flexibility for easy installation routing
  • Optimised Electrical Performance due to ePTFE dielectric and helically wrapped foil shield
Microwave Cable for Aircraft Key Characteristics:
  • Characteristic impedance: 50 Ω
  • Insertion Loss graph (Annexure B)
  • Velocity of propagation: 86% nom.
  • Time Delay: 3.9 ns/m nominal
  • Specially designed for aircraft applications
  • Has multiple layers of shielding materials

5.2. Space flight Microwave/RF Assemblies from Gore

Space flight Microwave cables are designed for use in the harsh environment of space. The cables use space flight approved materials. The specifications include: radiation resistance (Upto 100 Mrad), high power designs, low phase change cable, and lightweight cable.

Space flight Microwave Cable
  • Frequency range: DC to 65GHz
  • Low loss solid PTFE
  • 50 Ω
  • Nom capacitance 82 pF/m
  • Radiation resistant
Graph
  • Shield effective tested as per MIL-STD-1344, 90 dB/ft
  • Stable I/L and R/L
  • 4 ns/m time delay
  • Cable sizes: 1.2mm to 8.1mm
  • Connector options: SMA, MSSS™, 2.4mm, #12 contact, SMP and SMPM.

The space grade cable has to withstand high-energy radiation in space. Gore's standard assemblies withstand 30 Megarad, which is equivalent to an exposure of Cobalt 60 gamma radiation. Employing a unique radiation resistant jacket, the Gore cable assembly can withstand upto 100 Megarads, while maintaining its electrical and mechanical performance (Refer Annexure C).

Some of the standards applicable to space grade cable assemblies are referred to Annexure D.

6. LAN cable

LAN cables are used in structured cabling for computer networks such as Ethernet and ATM. These cables carry data signals such as telephony and video. These cables are specified by ANSI/TIA/EIA-568-A standards. The cable consists of twisted pair of wire for noise rejection and shielding for signal integrity.

Cable name Standard Cable description
CAT5E EIA/TIA 568B, ISO/IEC 11801
  • Solid bare copper conductor
  • Solid PE insulation
  • LSOH (low smoke zero halogen) or PVC sheathing  
  • RL 20 dB at 100 MHz
  • IL 0.22 dB/m at 100 MHz
  • 100 ohms nom impedance
  • Velocity of propagation: 68 %
  • Flame resistant IEC60332
  • Flame resistant IEC60332
  • Used in Ethernet applications
  • Available in UTP or FTP versions
CAT6E EIA/TIA 568B & ISO/IEC 11801
  • Solid bare copper conductor
  • Solid PE insulation
  • PVC sheathing
  • RL 17 dB at 250 MHz
  • IL 0.33 dB/m at 250 MHz
  • 100 ohms nom impedance
  • Velocity of propagation: 74%
  • Flame resistant IEC60332
  • Used in Ethernet applications
  • Available in UTP or FTP versions
CAT7E  EIA/TIA 568B & ISO/IEC 11801
  • Solid bare copper conductor
  • Solid PE insulation
  • PVC sheathing
  • RL 17 dB at 600 MHz
  • IL 0.49 dB/m at 600 MHz
  • 100 ohms nom impedance
  • Velocity of propagation: 79 %
  • Flame resistant IEC60332
  • Used in Ethernet applications
  • Available in FTP version

 7. Data Cable

Similar to the LAN cable, a group of cables comprise a segment called the data cable, which serve special purpose and applications. Essentially these cables are used for transmission of conditioned digital data signal for such wide applications like ATM data to control and audio data. Here we have listed down some of the data cables based on the classification provided by its typical usage. Some of these cables are listed below:

  • Data screened cable such as used in Structured installation, including ATM (155 Mbit/s) and Fast Ethernet applications. These cable conform to ISO/IEC 11801, EN 50173 and EIA/TIA 568-A specifications. These are structured FTP cable, which can operate upto 600 MHz.
    o Center conductor: 0,51 mm (AWG 24), plain copper core
    o Insulation: PE
    o Screening: polyester foil with Al layer, Cu tinned braiding
    o Sheath: PVC
    o Outer diameter: 7 mm
    o Impedance: 100 Ω ±15 Ω
    o Loop resistance: 170-Ω/km max.
    o Operating capacitance: 50 nF/km
  • Single Paired Screened Cable is a general-purpose foil screened single pair cables, frequently used in audio, data, and instrumentation applications. The cable is made of Polyethylene dielectric resulting is lesser signal loss compared to standard PVC insulation.
  • Two pair individually screened 22 AWG cable provide high level screening from external sources, together with a low level of cross talk between pairs. It is widely used in the security industry for CCTV, telemetry, computer and instrumentation applications.
  • Overall Screened Multi Pairs 24 AWG is a general-purpose twisted pair cable with overall screen. Widely used for computers, point of sale, control systems, and RS232 applications.
  •  EF CY data transmission cable has screen protection from EMI and is suitable for automation in production processes and robotics application because of its sheath design, which is abrasion and oil resistant.
  • Home automation cable is suitable for indoor telephone cables. It supports both analogue and digital signals for applications such as Telephone; Fax; Alarm systems (burglary or fire); Communication systems; Paging systems; Access control; Time and data control systems.
  • There is a type of galvanized steel wire braid cable, which is used as power control cable, in applications such as for measurement, monitoring and controlling machine tool manufacturing, plant engineering and on assembly lines and product lines. Due to the galvanised steel wire braiding, these cables can even be used under adverse operating conditions or when exposed to high mechanical strain.
  • Screened single pair cable is a general-purpose foil screened single pair cables with a small outer diameter, frequently used in audio, data, and instrumentation applications. Belden 8723 cable falls in this category. It conforms to the NEC CN standards.

8. Instrumentation Cable

Instrumentation Cable used for remote control, signalling, security systems, communications and sound/audio.

Applicable Standard Description
BS5308 These cables use:
  • Annealed solid copper or stranded or flexible conductor
  • Polyethylene insulation
  • Multicore option
  • 40 °C +70°C
  • 300 Volts
BS6231 These cables are suitable for internal wiring of appliances and switch, control, metering and instrument panels of switchgear, etc
ESI These cables conform to BS standards and have:
  • Tinned annealed copper wire, BS6350
  • PVC insulation BS7655
  • Multipair or multicore option
  • PETP tape screen
DEF std 61.12 part 4 and 5
  • Flexible tinned annealed copper
  • PVC insulation
  • PETP tape binder
  • Tinned copper wire braid screen
  • PVC sheath
  • Originally developed for military use, Defence Standard cables are designed for connection with ground, sea and air borne instruments and electronic equipment. They offer compact sizing, high working voltage and a large range of sizes both civil and military fields. Sheathed or armoured for direct burial or duct installation.

 9. Submarine Cable

Submarine cables have been deployed undersea to provide telecommunication and various other services (exploration, monitoring, geological, scientific etc) between countries and continents. Submarine or submersible cables also cater to the needs of telecommunication for on-board navigation ship, navy and submarine vehicles. Fiber optic cables and copper coaxial cables are the two preferred transmission medium to meet the bulk of communication requirement, such as the Internet, data, telephony and other services across the globe.

A submarine cable has certain salient features and requirements that are over and above the industrial or commercial grade cables. Some of these are listed below:

  • Withstand high pressure and weight of the water body
  • Water proof, rugged against the undersea elements
  • Salinity resistant
  • Flexibility with high pulling strength

As seen from the above discussion, the Submarine cables have stringent requirements on their construction. These requirements have been specified and standardized. These standards are mentioned in brief:

Type Applicable standard Description
Optical Fiber ITU-T G.971 General features of optical fibre submarine cable systems
Optical Fiber ITU-T G.972 Definition of terms relevant to optical fibre submarine cable systems
Optical Fiber IEC60794/IEC60331/ IEC60332/IEC61034/ IEC60811/IEC60754/NEK606 Steel armoured optical fibre cables are flame retardant, low smoke, halogen free and fire resistant, used for communication and emergency systems that need to be operational during fire
Coaxial copper GB 17502-1998 Specifications for submarine cable and pipeline route investigation
Coaxial copper IEC60092/IEC60754/ IEC60332/IEC61034/NEK606 Coaxial cable for ship & submarine installation

9.1. Example of Submarine coaxial cable

RG6 Armoured Coaxial Cable These 75Ω coaxial cables are suitable for installation on board of ships and other indoor marine environments.
Submarine Co-axial Cable Submarine Co-axial Cable
Applicable standards:
IEC 60092-350,
IEC 60332-3-22
IEC 60754-1,2
IEC 61034-1,2
NEK 606:2004
Construction:
Conductors: 18AWG solid bare copper.
Insulation: Foam PE.
Shielding1: Al/Polyester/Al tape.
Shielding2: Tinned copper braid.
Bedding: Low smoke and halogen-free polyolefin coloured black.
Armour: Copper wire braid.
Outer Sheath: Low smoke and halogen-free polyolefin.
Physical Characteristics:
Inner Conductor Diameter 1.0 mm
Nominal Insulation Thickness 1.8 mm
Nominal Sheath Thickness 1.2 mm
Nominal Overall Diameter 11.2 mm
Nominal Weight 208 kg/km
Electrical Characteristics:
AWG 18
Impedance 75+/-5 Ω
Nom Attenuation@1700MHz 29.4 dB/100m
Capacitance 53.5 pF/m
Velocity of Propagation 83 %
Conductor DCR 21.4 Ω/km
Shield DCR 7.5 Ω/km
Inductance 0.32 μH/m
Time Delay 4 ns/m
Temperature Range: -30ºC to +75ºC

10. Annexure

Annexure A

Some well know standards are listed below for reference.

Name of the Standard body Abbreviation Region Application
MIL Military International Defense
TIA Telecommunication Industry Association International Telecommunications, broadband, mobile wireless, information technology, networks, cable, satellite, unified communications, emergency communications and the greening of technology. TIA is accredited by ANSI.
EIA Electronics Industries Alliance USA Electronics, telecommunications
ISO International Organization for standardization International Standards for activities, such as agriculture and construction, through mechanical engineering, manufacturing and distribution, to transport, medical devices, information and communication technologies, and to standards for good management practice and for services.
IEC International Electrotechnical Commission International Electrical, electronic technology. Works with ISO, IEEE, ITU
IEEE Institute of Electrical and Electronics Engineers International Electrical, Electronics, Communications, Computer Engineering and Computer Science
ITU International Telecommunication Union (ITU) International UN agency. Information and communication technology.
DIN Deutsches Institute of Normung German Various industrial domains including connectors
EN European Standard European Engineering standards in variety of domains including cable
CENELEC European Committee for Electrotechnical Standardization European Authors EN and HD documents for various industries
ASTM American Society of Testing and Materials USA Authors specs for materials used in industries including Electronic, electrical, mechanical materials
NASA National Aeronautical Space Agency National and international Aerospace technology standards including communications
BIS Bureau of Indian Standards India Involved in standardization and certification of a variety of products
ANSI American National Standards Institute USA Standard body for industry wide products including telecom and electronics
BS British Standards UK Telecom, Manufacturing, agriculture, quality
NF Association française de normalisation France Industrial standards
JIS Japanese Industrial Standards Japan Industrial standards
GB Guobiao, Standard Chinese Industrial
FAA Federal Aviation Administration USA Regulator for civil Aviation, Aerospace

Annexure B

Insertion loss graph for Gore RF/Microwave cable assemblies for Aircraft applications is shown below. The graph shows the relative insertion loss for a group of typical cable assemblies. The characteristics of these cable types are shown in the table.

Insertion Loss Graph

Cable Type Frequency GHz Outer Diameter (Nominal) mm Mass (Nominal) g/m Minimum Bend Radius mm Temperature Rating* °C Crush Resistance kg/cm
01 18 4.55 41 12.5 -58°C to 105°C  17.8+
04 18 4.55 41 12.5 -58°C to 105°C 17.8+
02 18 6.96 105 25 -58°C to 105°C 17.8+
05 18 6.96 105 25 -58°C to 105°C 17.8+
08 18 7.25 137 25 -58°C to 105°C 17.8+
0B 18 7.50 128 38 -58°C to 105°C 17.8+
06 18 9.50 190 50 -58°C to 105°C 17.8+
0E 18 9.93 204 55 -58°C to 105°C 17.8+
0L 6 12.7 345 62.5 -58°C to 105°C 17.8+

Annexure C

The graph below shows the effect of radiation on insertion loss versus frequency variation on a 8.1 mm radiation hardened cable.

Insertion Loss Versus Frequency Variation

Annexure D

Some of the standards applicable to the space grade cable assemblies are shown below.

Cable assembly component Applicable Standards
Material specifications Federal specifications such as AMS-QQ-‘X’ and QQ-‘X’ series, ASTM-A, B and D series
Electrical shield IPC-FC-221, MIL-C-17
Mechanical shield ASTM-B-298, MIL-C-17
Military specifications and standards
RF flexible and semi-rigid cable specifications MIL-C-17
Coatings, electro less Nickel MIL-C-26074
Coaxial Assembles MIL-C-87104
PTFE MIL-P-19468
RF Coaxial Connector MIL-PRF-39012
Test methods for parts MIL-STD-202
Test methods for connectors MIL-STD-1344
Aerospace Specifications
Solder electrical connections NASA-STD-8739.3
Other standards and specifications
Precision coaxial connectors IEEE STD 287
Requirements for soldering J-STD-‘X’
Connector related ASTM-B-196, ASTM-A-582, ASTM-B-488, MIL-G-45204, MIL-G-45204, MIL-C-26074
C-ring ASTM-B-196
Center contact ASTM-B-196, ASTM-A-582
Plating ASTM-B-488, MIL-G-45204, MIL-C-26074
Dielectric related (PTFE) ASTM-D-5205, MIL-R-46198, ASTM-D-1457
Jacket material MIL-C-17

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