Coaxial Cable Types Guide

Coaxial cables are widely used in transmitting radio frequency (RF) signals across various applications, including telecommunications, broadcasting, and military systems. Their design ensures reliable performance, making them essential for high-quality signal transmission. This guide explores the different coaxial cable types, their structures, and their specific applications, along with a detailed comparison to help you make informed decisions.

Table of Contents

What Is a Coaxial Cable?

A coaxial cable is a specialized electrical cable designed for carrying high-frequency signals with minimal loss and interference. It consists of a center conductor surrounded by an insulating layer (dielectric), a conductive shield, and an outer protective jacket. This concentric structure helps maintain signal integrity by preventing electromagnetic interference and signal leakage, making it ideal for applications like cable TV, internet connections, radio communications, and other high-frequency signal transmissions.

Structure of Coaxial Cable

Users like coaxial cables, of course, because they have excellent signal transmission performance, high transmission frequency, good anti-interference ability and stable signal quality. Especially in audio systems, coaxial cables can ensure the clarity and accuracy of the signal transmission process.

All coaxial cables are inseparable from the “center conductor-insulation layer-shielding layer-outer sheath” structure.

The center conductor is the core part of the coaxial cable, which is mainly responsible for the transmission of electrical signals and is usually made of copper, silver-plated copper and other materials. There is an insulating layer surrounding the center conductor, the main function of which is to separate the center conductor from the external shielding layer and maintain the characteristic impedance of the cable.

Outside the insulating layer is a metal shielding layer, which plays a shielding role against electromagnetic interference and radio frequency interference, which can prevent the leakage of cable transmission signals and prevent external signals from interfering with coaxial transmission signals. The shielding layer is made of a variety of materials, such as metal braided aluminum foil, copper foil, copper wire, etc.

Finally, there is the outer layer protection of the coaxial cable, which is in direct contact with the external environment to protect the inside of the cable from external interference and damage. Like other types of wires, the outer layer protection is generally made of PVC, PE and other materials.

How Do Coaxial Cables Work?

The high-frequency current transmitted by the center conductor of the coaxial cable can be regarded as an antenna that emits radio waves outward, which is essentially a kind of “alternating current”. Recall the knowledge of junior high school physics, “the direction of alternating current will change periodically, and it will reverse several times within one second.” In order to reduce the impact of the uncertainty of the current direction, the design of the coaxial line adds “mesh conductive layer isolation”, that is, the shielding layer, which can control the radio waves emitted by the center conductor by grounding.

However, the current transmission process is not so smooth. If a section of the coaxial wire encounters a relatively large extrusion or distortion, it is likely to cause the internal radio waves to reflect back to the signal transmission source, affecting the signal quality at the receiving end. Therefore, in order to overcome this problem, it is necessary to add a layer of insulator between the center conductor and the shielding layer to ensure that the distance between them is consistent and maintain the stability of the current signal transmission.

Coaxial Cable Types

The variety of coaxial cable types available allows for tailored use in specific applications. Below is an in-depth look at common types:

RG-Series Cables

RG (Radio Guide) series cables are standardized coaxial cables types originally developed for military applications. Each type has specific characteristics optimized for different uses and environments.Several of the RG coaxial cable types used are described in detail below:

RG-6/U

RG-6 is a high-performance 75-ohm coaxial cable primarily designed for digital cable TV and satellite installations. It features superior shielding with a quad-shield design and an 18 AWG conductor, making it larger than RG-59. Its construction enables excellent high-frequency digital signal transmission with minimal loss, making it particularly suitable for long cable runs in modern digital applications.

  • Impedance: 75 Ohm
  • Core size: 1.024 mm
  • Dielectric Type: PF
  • Nominal Attenuation per MHz (dB/100 ft):850/8.5dB; 1900/13.6dB

RG-8

RG-8 is a high-performance 50-ohm coaxial cable with a 13 AWG center conductor, optimized for demanding RF applications. Its robust construction delivers excellent power handling and low signal loss. With superior shielding and both solid and stranded conductor options, it’s ideal for amateur radio base stations and professional RF installations.

  • Impedance: 50 Ohm
  • Core size: 2.17 mm
  • Dielectric Type: PF
  • Nominal Attenuation per MHz (dB/100 ft): 850/6.4dB; 1900/10.4dB

RG-11

RG-11 is a professional-grade 75-ohm coaxial cable distinguished by its large 14 AWG conductor size and superior signal-carrying capacity. Featuring comprehensive quad shielding and the lowest signal loss among common cables, it excels in HDTV and professional video applications. Its robust construction makes it the preferred choice for long-distance signal transmission where maximum performance is required.

  • Impedance: 75 Ohm
  • Core size: 1.67 mm
  • Dielectric Type: PF
  • Nominal Attenuation per MHz (dB/100 ft):850/6.25dB

RG-59

RG-59 is a 75-ohm coaxial cable widely used in analog video and CCTV systems. Its 23 AWG conductor and flexible shield design suit space-constrained installations, offering cost-effective analog signal transmission for shorter runs.

  • Impedance: 75 Ohm
  • Core size: 0.64 mm
  • Dielectric Type: PF
  • Nominal Attenuation per MHz (dB/100 ft):N/A

LMR-Series Cables

The LMR-series cables, manufactured by Times Microwave Systems, are flexible, low-loss coaxial cable types designed for RF communications. These cables are suitable for outdoor and indoor installations, offering excellent weather resistance and high performance across various applications. Below is a detailed comparison of different LMR cables:

Cable Type Impedance (Ohms) Core Size (mm) Dielectric Type Nominal Attenuation per MHz (dB/100 ft) Applications
LMR®200 50 1.12 PF 850/9.6 dB; 1900/14.6 dB Short antenna feeder runs, low-PIM applications
LMR®240 50 1.42 PF 850/7.2 dB; 1900/11.2 dB GPS, WLAN, mobile antennas
LMR®400 50 2.74 PF 850/3.8 dB; 1900/5.8 dB Jumper assemblies, wireless systems
LMR®600 50 4.47 PF 850/2.4 dB; 1900/3.8 dB Long antenna runs, microwave systems
LMR®900 50 6.65 PF 850/1.6 dB; 1900/2.6 dB Medium antenna feeder runs, flexible RF setups
LMR®1200 50 8.66 PF 850/1.2dB; 1900/1.9dB Large-scale RF installations
LMR®1700 50 13.39 PF 850/0.9dB; 1900/1.5dB Ultra-long-distance communications

Highlights of LMR Cables:

  • LMR®200: Compact and flexible, this cable is perfect for short-range connections like antenna feeder runs and applications requiring low PIM.
  • LMR®240: Balances flexibility and low attenuation, making it ideal for GPS systems, WLAN, and mobile antenna setups.
  • LMR®400: Designed as a replacement for RG-8 cables, it excels in jumper assemblies and wireless communication systems that require repeated flexing.
  • LMR®600: Known as the “Half-Inch” cable, it provides superior signal quality for long-range RF runs and is easier to handle than air-dielectric cables.
  • LMR®900: Larger and designed for medium antenna feeder runs, this cable offers low loss and high flexibility for a range of applications.
  • LMR®1200 & LMR®1700: Ideal for large-scale and ultra-long-distance RF applications, these cables provide exceptional performance and durability for demanding installations.

Hardline Coaxial Cable

Hardline coaxial cables are designed for high-strength transmission and are commonly used in military signals, broadcasting radio, and connecting ground-level transmitters to aerial receivers. These coaxial cable types feature thick diameters (≥ ½-inch) and are constructed with materials like copper, silver, aluminum, or steel for the center conductor and shield. A dielectric buffer, such as polyethylene foam or pressurized nitrogen, is often added to prevent arcing and moisture contamination. The shielding can vary from rigid tubing to corrugated materials, making them suitable for robust applications requiring durability and reliability.

Radiating Coaxial Cable

Radiating coaxial cables, also known as “leaky cables,” have a unique design that incorporates slots cut into the shield. These slots are tuned to specific wavelengths, allowing controlled signal leakage. These coaxial cable types are ideal for environments where traditional antennas are impractical, such as tunnels, elevators, or underground facilities. By enabling a pre-determined amount of signal transmission between the transmitter and receiver, radiating cables provide consistent and reliable coverage.

Twinaxial Coaxial Cable

Twinaxial, or “Twinax,” cables are a specialized type of coaxial cable that features two central conductors instead of one. These coaxial cable types are widely used for high-speed, short-range signaling applications, such as in data centers or network hardware with SFP+ interfaces. The dual-conductor design allows Twinax cables to achieve faster data transmission rates while maintaining minimal interference, making them a popular choice for modern networking systems.

Semi-Rigid Coaxial Cable

Semi-rigid coaxial cables feature a PTFE-supported dielectric and a solid conductor shield, offering superior dielectric properties for high-frequency applications. These coaxial cable types are limited in size and frequency transmission but provide excellent performance in environments requiring precision and minimal signal loss. Their rigid structure makes them suitable for aerospace and defense systems.

Triaxial Coaxial Cable

Triaxial, or “Triax,” cables are an advanced variation of coaxial cable types that include an additional layer of insulation and a second conductive sheath. This design provides superior bandwidth and enhanced interference protection, making these cables ideal for applications in television production and environments with high electromagnetic interference. Although more expensive than standard coaxial cables, Triax cables deliver exceptional performance and reliability in demanding use cases.

Rigid Line Coaxial Cable

Rigid coaxial cables are constructed with two copper tubes and a PTFE dielectric buffer supported at intervals along the cable. These coaxial cable types are significantly larger, with diameters ranging from ⅘-inch to 8⁳/₁₆-inch, and are designed for high-power capacities. Rigid lines are commonly used for TV and FM frequencies, supporting multi-channel transmission with minimal loss. Due to their robust design, they are ideal for large-scale broadcasting and industrial applications.

Factors to Consider When Choosing a Coaxial Cable Type

Selecting the appropriate coaxial cable requires careful consideration of the application, environmental factors, impedance specifications, and physical attributes of the cable. Matching these factors ensures optimal signal transmission, longevity, and reliable system performance. Assess your project’s unique requirements to make a well-informed and effective choice.

Factor Considerations
Impedance Match the impedance of your equipment to avoid signal reflection and loss.
Attenuation Lower attenuation is better for long distances and high-frequency signals.
Frequency Range Ensure the cable supports the frequency of your application.
Durability Select a cable with the appropriate jacket material for your environment.
Flexibility For tight spaces or mobile setups, choose flexible cables like RG-58 or LMR-240.
Shielding Double shielding is preferred in high-interference environments.
Length Longer runs require cables with lower attenuation (e.g., LMR-400 or RG-11).

Some FAQs

What are the three types of coaxial cable?

The three common coaxial cable types are:

  • RG-Series Cables: Versatile for residential and commercial applications.
  • Hardline Cables: Used for high-power transmissions like broadcasting.
  • Radiating Cables: Designed for controlled signal leakage in environments where antennas are impractical.

Which is better, RG6 or RG11 coaxial cable?

RG11 is better for long-distance transmissions due to lower signal loss, while RG6 is more flexible and suited for short runs, such as indoor connections for cable TV and internet.

What is RG-8 and RG11 coaxial cable used for?

  • RG-8: Commonly used for high-power RF applications, including ham radio and antenna connections.
  • RG-11: Ideal for long-distance installations, such as outdoor cable TV or satellite connections.

How do I know what type of coax cable I have?

Check the cable’s printed markings, which typically include its type (e.g., RG6, RG11). You can also measure its diameter and compare it to specifications, or examine its construction (e.g., conductor size, shielding, and jacket material).

Conclusion

Choosing the right coaxial cable types depends on your specific application, environmental conditions, and performance requirements. RG-series cables are suitable for general use, while LMR-series and specialized coaxial cable types like hardline, radiating, and Twinax cables cater to professional-grade installations. Understanding the differences among coaxial cable types ensures optimal performance and longevity for your communication systems.

Audio Video Connecrtor Factory Sales Engineer_pixian_ai

Hi, I am the author of this article, I have been in this industry for more than 5 years. If you want to wholesale audio plug cables or audio accessories related products, please feel free to ask me.

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