Coaxial Cable Comparison Guide: How to Choose the Best One for Your Application

Coaxial cables are important cables used for a variety of purposes, including television, the Internet, antennas, etc. However, when it comes to purchasing one, there are so many different types that many people may be unsure which one to choose.

This article will explain in detail the key points to consider when choosing a coaxial cable.

What is Coaxial Cable?

Coaxial cables are cables designed to stably transmit high-frequency signals.

By covering the central conductor with an insulator and protecting the outside with a metal outer conductor (shield), it is possible to smoothly exchange video and communications while reducing external noise.

It is used in a wide range of fields, including television broadcasting, Internet lines, and wireless communications, and its main feature is that it has a characteristic impedance of "50 Ω", "75 Ω", etc., depending on its structure.

Furthermore, since attenuation and durability vary depending on the shielding method and cable thickness, it is necessary to select the optimum one for the application and installation environment.

Coaxial cables have a high electromagnetic shielding effect due to their outer conductor, and are widely used as a means of stable signal transmission.

In today's world, where we deal with high-frequency communications and high-definition video, coaxial cables play an important role in supporting the devices that we use every day. They are used in a wide range of applications, from indoor wiring to outdoor antenna connections, and by selecting the right cable, you can reduce noise and loss and maximize performance.

Types of Coaxial Cables

Coaxial cables are often broadly divided into two design standards: JIS standards (Japanese Industrial Standards) and MIL standards (US military standards).

Product numbers for JIS standard products widely used in Japan often include notations such as "3C-2V" and "5C-FB," while representative MIL standard products that are widely used overseas include "RG-58" and "RG-59."

Cables based on either standard have the same basic structure: "center conductor + insulator + outer conductor (shield) + jacket." However, there are differences in small details such as outer diameter, frequency characteristics, and number of shield layers, so when selecting a cable, it is useful to understand the relationship between the application and the standard.

Since the degree of signal attenuation changes depending on the thickness (outer diameter), it is important to first determine "how many meters of length is needed" when choosing a coaxial cable.

Depending on ease of handling and the installation environment, you will need to compare several candidates, including considerations such as whether they are for indoor or outdoor use and whether they are waterproof.

Connector shapes also vary depending on the application, including BNC connectors, F-type connectors, and N-type connectors.

Because of this diversity, it is best to clarify the purpose and installation environment in advance to make a smooth cable selection.

How to Choose a Coaxial Cable

There are five points to keep in mind when selecting a coaxial cable:

• Cable thickness and length
• Signal frequency
• Car wash
• Characteristic Impedance
• How to choose according to purpose

Consider all of these factors and choose a coaxial cable that best suits your purpose and environment.

We will explain each item in detail.

Cable thickness and length

The thicker the cable, the less signal attenuation tends to occur.

On the other hand, thin cables are easy to handle, but over long distances they have a large loss and are prone to signal level degradation. This point of view is important because it is necessary to choose a cable that is physically easy to wire while preventing unnecessary attenuation.

As shown below, the commonly used notations are 3C, 4C, 5C, etc., and the larger the number, the thicker the outer diameter.

Cable thickness	直径	Appropriate Cable Length	Recommended use
3C	About XNUM X mm	Less than 3m	Short connection as a TV peripheral
4C	About XNUM X mm	Less than 10m	Commonly used for indoor wiring
5C	About XNUM X mm	10-20m	For outdoor wiring and long distance transmission
7C	About XNUM X mm	20-50m	Shared cabling throughout the building

Reference: DX Antenna Co., Ltd. (February 2025) "Please tell me the thickness of the coaxial cable," DX ANNETA official website, URL (https://qa.dxantenna.co.jp/faq_detail.html?id=2&category=2814&page=78)

For example, if you want to connect a TV and a recorder for only a few meters, 3C or 4C is often sufficient. However, if you are connecting an outdoor antenna to a home device and running a cable over 10m, using a thicker cable with less attenuation, such as 5C or 7C, will help prevent image distortion.

In addition, if you choose a product with sufficient shielding, it will be easier to suppress the effects of external noise. Waterproofing and weather resistance are also important when used outdoors, and cables that prevent deterioration due to rain and UV rays will last longer.

If the installation location is narrow and winding, it may be difficult to wire a thick cable. As such, you should consider the spatial conditions in your home or building, the wiring distance, and the frequency band, and then choose the appropriate thickness and length.

The trick is to find the optimum balance between ease of use and signal degradation.

Signal frequency

The required cable characteristics change depending on the frequency of the signal being handled.

The frequency bands used for television broadcasting range from several hundred MHz to several GHz for satellite broadcasting, and 4K8K broadcasting reaches even higher frequencies.

On the other hand, wireless communications and mobile base stations generally use high frequency bands of 1 GHz or more. The higher the frequency band, the greater the effects of attenuation and reflection, so the more stringent the demands on shielding precision and conductor quality.

The higher the frequency of radio waves, the greater the loss that tends to occur when passing through a cable. When handling high frequencies, care must be taken because if the quality of the cable's conductors or insulators is low, the transmission efficiency will decrease.

In addition, the higher the frequency, the more susceptible the cable is to noise interference, so the number of layers of the shield and the material used will affect performance. For example, if you want to fully enjoy 4K8K broadcasts, it is safer to choose a cable that claims to be 4K8K compatible. These products often have reinforced shielding to accommodate higher frequency bands.

Like wireless LAN, frequencies can reach 2.4 GHz and 5 GHz even when used indoors. In such environments, it is a good idea to check whether the device is designed to transmit securely in the 5 GHz band.

Car wash

There are various types of connectors that are attached to the end of coaxial cables, including F-type, BNC-type, N-type, and SMA-type.

Since connectors of different shapes cannot be directly connected to each other, it is necessary to use a connector that matches the terminal of the device. The types of connectors and their features are summarized below.

Connector Type	Features
F-type connector	This type is often used for TV antenna terminals. There are screw-type and slide-type terminals, and they are relatively easy to use, but if used outdoors, they require waterproofing and rust-proofing.
BNC Connector	Widely used in broadcasting and measuring equipment. The bayonet mechanism allows the device to be attached by simply rotating it a few dozen degrees, making it suitable for environments where attachment and detachment are frequent.
N-type connector	Often used in wireless communication devices and base stations, these are characterized by their large size and robustness. The screw-in type makes them highly durable outdoors and easy to use in high frequency ranges.
SMA Connectors	A small, specialized type for high frequencies. Used in antennas for wireless LAN routers and mobile base stations, the screw-in type provides a stable connection.

Attaching a connector that is mechanically and electrically compatible is essential to bringing out the inherent performance of a coaxial cable.

Characteristic Impedance

Coaxial cables have a characteristic impedance of 50Ω or 75Ω.

There are many JIS standard cables available that are 75 Ω for terrestrial and BS/CS broadcasting, and many MIL standard cables that are 50 Ω for wireless communication. When choosing which cable to use, it is essential to check the specifications of the device to be connected and match the impedance.

This is a value that indicates how difficult it is for current to flow in an AC circuit, and it affects the signal transmission efficiency and the presence or absence of reflection. The characteristics of 50 Ω and 75 Ω are as follows.

50Ω	It is mainly used in wireless communication, business communication equipment, wireless LAN, mobile base stations, etc. It is designed to transmit efficiently even in high frequency bands, and is also the standard impedance for measuring instruments.
75Ω	It is often used for video-related purposes such as television broadcasting, video signals, and cable television lines. It is designed for video transmission and is widely used in a wide range of broadcasting formats such as BS/CS and 4K8K.

The connected devices are also designed to match these impedances, so by choosing the appropriate cable, signal reflections and power loss can be reduced.

If you connect with the wrong impedance, it may cause video distortion or a drastic drop in communication speed. The first step to achieving good signal transmission is to remember to check the impedance.

How to choose according to purpose

Since the optimal specifications for coaxial cable vary depending on the intended use, you must first determine what devices you want to connect and over what distances.

Here we will introduce some typical uses and points to consider when selecting one.

Television broadcast

• Impedance: 75 ohms is the standard
• Broadcast format: Check whether it supports high frequency bands such as terrestrial, BS/CS, and 4K8K.
• Cable thickness and length: If you are wiring a long distance from the outdoor antenna to the inside of your home, a thicker cable of 5C or more is safer.
• Connector: F-type connectors are common. Waterproof connectors are recommended for outdoor use.
• Installation location: When wiring on exterior walls or roofs, choose cables that prioritize weather resistance and noise suppression.

Internet (cable TV line)

• In line with the provider: If the cable TV company specifies a cable standard, follow that specification.
• Frequency band: Different frequencies are often used for downloads and uploads, so it is best to choose a cable that supports wideband.
• Connector shape: Check the terminal of the carrier or modem and match it to F-type or other special connector.
• Outdoor wiring: In some cases, optical fiber and coaxial cable are used together, and the length is determined with an emphasis on waterproofing and weather resistance.

Wireless devices and antennas

• Impedance: As a rule, choose 50 Ω.
• Frequency: Cable loss varies depending on the frequency band, be it VHF, UHF, or even higher. Emphasis is placed on shielding performance and conductor quality.
• Connector type: Choose from BNC, N, SMA, etc. to match the terminal of the device.
• For wireless devices to be installed outdoors, a robust type such as N type is preferable.

When using outdoors

• Waterproof performance: Use waterproof connectors or waterproof tape to prevent short circuits caused by rain or condensation.
• UV resistance: The cable's outer sheath is prone to deterioration when exposed to sunlight for long periods of time, so consider using UV-resistant materials.
• Handling: When laying cables according to the shape of the building, thick cables require a larger bending radius.

Taking these factors into consideration will help you narrow down the coaxial cable that best suits your needs.

When making your final selection, it's important to compare basic specifications such as impedance, frequency compatibility, shielding performance, and length.

Points to note when selecting coaxial cables

No matter how well you choose the cable, if there is a problem with the wiring method or storage conditions, the cable will not perform as well as it should.

Here are five points to keep in mind.

・Processing of connection parts

If the connector is not installed properly, problems are likely to occur due to signal leakage or increased contact resistance.

The crimping method using a tool is easier to achieve a stable connection, but it must be done carefully as there is a chance of failure if you are not familiar with it.

・The importance of earthing

In systems that handle high frequencies, properly grounding the shielding makes it harder for noise to flow.

In some cases, outdoor antennas are combined with lightning arresters to prevent lightning surges from entering the antenna.

Reduce the number of extensions

The more cables you connect, the more likely it is that loss and noise will occur at the connectors.

If possible, it's best to buy the length you need in bulk.

・Bending radius

Bending or folding a cable forcibly can cause the internal structure to deform, leading to a deterioration in its characteristics. Each product has a recommended bending radius, so be sure not to wire it below that.

Storage environment

When storing unused cables, avoid storing them in direct sunlight and away from moisture. If the outer sheath is damaged, moisture may get inside, causing noise or disconnection.

Summary

Coaxial cables play an important role in ensuring the stable transmission of all high-frequency signals, from television images to the Internet and wireless communications.

When selecting a coaxial cable, it is important to comprehensively consider the following points:

• Use: TV broadcast, wireless communication, or internet
• Thickness and length: Affects attenuation and ease of handling
• Impedance: 50Ω or 75Ω depending on the device specifications
• Frequency band: The higher the frequency, the greater the need for shielding performance.
• Connector type: F-type, BNC, N-type, SMA, etc. Does it fit the device terminal?

By choosing the appropriate coaxial cable, you can achieve stable signal transmission and create a comfortable TV and Internet environment. Please take into consideration the points explained in this article and choose a coaxial cable that suits your needs.