How To Make BNC Cables?

How to make BNC cables? Manufacturers attach BNC connectors with coaxial cables for transmitting high-quality video and radio signals with reliable and smooth signal quality.

Before BNC, the industry used other different types of connectors with coaxial cables.

However, installing those connectors each time during their use was difficult.

Furthermore, those connectors were also prone to signal loss.

Electrical engineer Carl Concelman constructed the BNC connector as an ideal solution to overcome signal-related problems observed in other connectors.

BNC cable understanding

Bayonet Neill–Concelman (BNC) connector is an RF connector for terminating a variety of miniature to standard RG coax cables.

BNC Connectors’ Composition

The BNC male connector consists of the body, sleeve, and pin.

The pin lies at the center, surrounded by a dielectric material (sleeve). 

The main body is brass with a locking mechanism, which you can use to achieve a reliable and secure connection between the cables. 

You can latch female BNC connectors with two lugs positively or in reverse with a quarter turn to connect or disconnect with the male connector.

Electrical engineers manufacture BNC connectors in two types, 50 and 75-ohm versions.

Both BNC connectors have a gold-plated outer casing to prevent corrosion and increase durability. Additionally, they are lightweight, easy to use, and reliable.

75 Ohm BNC Connectors

75-ohm BNC connectors consist of outer and inner conductors.

The outer casing of the connector is gold-plated to protect it against corrosion, whereas the inner conductor (pin) is made of brass and has a consistent diameter.

75-ohm BNC connector uses Teflon as a dielectric.

It is responsible for insulating the outer and inner conductors from each other to maintain consistent impedance.

Lastly, these connectors use air to direct their outer spring fingers.

50 Ohm BNC Connectors

50-ohm BNC connectors are a little different from 75-ohm connectors in composition.

This BNC connector consists of a similar outer casing, inner conductor, or pin.

However, instead of Teflon, it uses Delrin as a dielectric to insulate the outer and inner conductors from each other.

Furthermore, unlike 75 Ohm BNC Connectors, 50 Ohm BNC inner conductors (pins) don’t have a consistent diameter.

Additionally, it tends to increase as you get nearer to the crimp region.

BNC Connectors’ Termination

BNC Connectors are easy to connect or disconnect with the coax cable with just a quarter turn.

It provides devices with easy, retractable, and reliable connection points for rapid swapping.

BNC Connectors’ Application

Initially, BNC Connectors were designed to be used by the US Military during wartime.

However, these connectors were later introduced into the industry for commercial use and are valid today.

BNC Connectors gained popularity worldwide due to their high-quality signal transmission attributes.

Some common applications that use BNC connectors and cables are:

  • Aerospace electronics.
  • Broadcast (75 Ohms).
  • Parallel and serial video signal devices.
  • Cable Modems.
  • Automotive wireless devices.
  • Computer Lan Equipment.
  • Medical Equipment.
  • And more.
BNC connectors for crimping

BNC connectors for crimping

75-Ohm BNC cable and digital transmissions

75 Ohm connectors can transmit signals up to 2 GHz of frequency.

Although old, they are still perceived as one of the best mediums for transmitting digital signals.

Digital signals are different from analog signals in terms of their wave formation.

The former produces excellent square waveform, whereas the latter produces sine waves.

Digital signals distort when transmitted through coaxial cables with high capacitance, leading to diminished distinctions between the stepped peaks and troughs of the digital signals.

However, that is not the case with a 75 Ohm connector because it has low capacitance as compared 50 Ohm coax.

As a result, it successfully transmits the digital signals down the line in high quality with minimal loss.

Electrical engineers use it for digital audio and video broadcast applications.

The two variations of coaxial cables that use a 75-ohm BNC connector are the following:

RG-179: This coax cable uses a specially designed 75-ohm BNC connector to withstand excessive temperatures up to 200 Celsius.

Technicians use this cable in a high-temperature environments in hospitals and clinics. Several businesses also use them in their Audio and Video security systems.

RG-59: The coaxial cables use a 75-ohm BNC connector to transmit high-quality video signals from the CCTV camera to the monitor room.

50-ohm BNC cable and power handling

50-ohm BNC cables and connectors can transmit signals up to 4 GHz.

Technicians have used these cables for over 50 years to handle high profiles and low attenuation.

Furthermore, these cables can handle power over 100 watts or more.

On the other hand, these cables are also used in applications that use transmitters and receivers across wireless and cellular networking.

 The three variations of coaxial cables that use 50-ohm BNC connectors are the following:

RG-58:  This coaxial cable uses a 50-ohm BNC connector due to its high-quality performance in various applications.

RG-174: This coaxial cable uses a 50 Ohm BNC connector due to its wide range of applications in the GPS navigation transmitters. Furthermore, they’re also thin in terms of their size.

RG-213: This cable is the thickest of all the coaxial cables. It uses 50 Ohm connector to handle high power, 1000 watts or more.

How to install BNC Connector on a coaxial cable?

Although it’s cheaper and better to purchase the BNC cables from a local shop, there might be a few instances where you might need to repair them on your own. 

Prepare the tools

The tools that you’ll need for installing BNC connectors are the following:

  1. Cutters for trimming the cable.
  2. Excellent coaxial cable stripper to strip the cable accurately and avoid open or short circuits.
  3. High-quality crimp tool for handling crimps of various sizes.
  4. Network cable tester.
  5. A standard test meter, in case you don’t have a cable tester.

Show the connectors

This article will discuss the process for using a three-part BNC connector.

Get the RG59 Cable

This article will discuss the process for using an RG59 cable, the most common 75-ohm coax connected with the BNC connectors.

Manufacturers use these cables because they are reliable, easy to use, and cheap.

The RG59 cable consists of an outer conductor, an inner conductor, outer coverage, and a dielectric.

A dielectric surrounds the inner or central conductor. This dielectric keeps the inner and outer conductors separated from one another.

A braided shield or outer conductor surrounds the dielectric to prevent electromagnetic interference.

Ensure the correct matching of cables and connectors

It’s important to ensure that the connector must have the same impedance as the cable while assembling BNC cables.

For example, a 75 Ohm cable must contain a 75 Ohm BNC connector to ensure smooth transmission of signals.

The impedance will be mismatched if you connect a 50 Ohm BNC connector with a 75 Ohm cable.

It would cause reflection of energy leading to distortion of signals and generating standing waves, which would eventually degrade the signals, rendering the image unreadable and unrecoverable.

Making the cable

First, you’ll need to cut the cable to the desired length while leaving enough room for cable connection. 

Once done, twist the cable using a cable tie to keep it in order. 

Keep the connector components ready. It has three components: plug body, sleeve, and center pin.

We advise using a Tupperware container to keep all components organized and easily accessible. 

The next step is sliding the sleeve over the cable before stripping it.

Once done, strip the cable accurately using the multi-dimensional coaxial cable stripper without damaging the components. 

Then move the center pin through the center core into the plug body. Use the crimp to fix it permanently until you hear a click indicating it has locked in its place.

Next, slide the sleeve over the plug system until it touches the plug body. 

After that, use the crimp tool to completely fix the sleeve over the cable and the plug body.

Make sure to squeeze it so the jaws release in the opposite direction of the cable. 

Repeat the similar process for the other side of the cable.

Testing the cable

Technicians, once they have made the cable, test the cable to determine the presence of a short or open circuit.

You can use the network cable tester or a normal test meter.

BNC cables

BNC cables


However, building BNC cables is labor intensive and expensive task.

Factory-prepared cables, leads, and connectors are better in terms of transmitting high-quality signals than homemade ones.

At Cloom Tech, we make sure you get the BNC Cables of your choice.

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