A Complete Guide to Coaxial Connectors

Coaxial or coax cables are electrical cables created to carry high frequency, multi-megahertz electrical signals. They contain an inner conducting wire, usually copper, surrounded by a protective double insulating layer and then an outer plastic sheath, giving them a distinctive appearance.

Coaxial cables are durable, easy to install, and have a broad range of uses. Their design allows rapid signal transmission (around 10 megabits per second) with minimal electro-magnetic interference or signal loss. Coaxial cables are the default cabling choice for many low voltage consumer electronics.

These include:

• Televisions and telephones
• Mobile phones
• Satellite dishes
• Broadband routers
• Antennas
• Radio equipment

Coaxial cables are available in a variety of types, distinguished by their gauge and impedance. Gauge refers to the thickness of the cable and is given a given a Radio Guide or RG number, with higher numbers indicating thinner conducting cores. Impedance refers to the level of electrical resistance in the wire. Most coaxial cables have an impedance of either 75 or 50 Ohm. The former is primarily used for video signals and the latter for data.

Coaxial cables can come in many sizes, including:

• RG-12
• RG-58
• RG-62
• RG-213

Coaxial cables are used for many different purposes and so the connectors are equally varied. Each type and size is carefully designed to mesh seamlessly with the host cable and function in different, sometimes quite tough conditions. They must resist stressors such as impact, pressure, high temperature and vibration.

Coaxial cables made for radio frequency (RF) transmission require special connectors that provide consistent electrical resistance at the point of connection with connected cables. This means that they are somewhat delicate and can be damaged easily.

The major types of coaxial connector are as follows:

When selecting a coaxial connector, you will need to know the key parameters of the cable you plan to connect. These include:

• The voltage
• The environment
• The required frequency
• Whether a male or female connection is required. Male connectors have protruding metal pins while female connectors have a recess designed to receive the pins

Coaxial Connector Gender Types

In electrical engineering, coaxial and other electrical cables are conventionally divided into two types: male and female. The former typically have a connecting pin or protrusion of some kind that is inserted into indentations or slots in the latter – for example, plugs and sockets (also known as jacks). Connecting a male to a female connector is referred to as ‘mating’ them.

Coaxial cable genders were designed not just to allow physical connections but also to ensure that power or signal data flows in the correct direction, from male to female connectors with matching electrical polarity, preventing interference and unsafe installations. Typically, female connectors are more resistant to damage than male ones so these tend to be placed in crucial areas with males relegated to connecting cables, which can be replaced more easily.

Note that the terms ‘male’ and ‘female’ are not universally used, especially in relation to lower voltage domestic appliances. Widely used electrical standard IEC60320 does not specify gender types for the latter.

Male Coaxial Connectors

Male coaxial connectors typically have a straightforward design, combining a central pin designed to fit a compatible plug on the female connector, alongside a spring-loaded electrical contact point located at the side.

Female Coaxial Connectors

Female coaxial connectors normally feature a metallic tube designed to precisely contain the corresponding male pin, normally called the tip. This is surrounded by an insulating layer and then an outer cylinder, typically referred to as the barrel or sleeve. The latter functions as an electrical contact point, alongside the inner tube.

Genderless Coaxial Connectors

Genderless coaxial connectors combine male protrusion points and female slots in the same connection point, enabling these to be connected to either male or female connectors of matching size and type. They allow cabling within complex installations to be repurposed or reconnected quickly, without awkward removal and repositioning if it needs to be connected to a different component or cable. They have a reverse electrical polarity, with a pin protruding from the female socket and slot in the male plug designed for that pin.

Genderless coaxial connectors are also known as combination connecters. They are not the right choice for installations in which a carefully controlled flow of current in a single direction is required for safety or functionality reasons.

How Do You Connect or Change a Coaxial Connector?

Coaxial cables and their corresponding connectors have different uses but the fundamentals of connecting or replacing them remain much the same. Here is how to conduct this procedure:

1. Ensure that the cable is removed from any power sources. Electrical shocks and injuries could result from adjusting a live coaxial cable
2. If there is already a connector in place, remove it. It may respond to a simple twist or you may need to make use of a tool such as a construction knife or wire strippers
3. Prepare the coaxial cable, using a wire stripper or similar device. Make a small incision towards the end of the cable, deep enough to expose the underlying copper, and then a second cut in the outer jacket of the cable – in both cases being careful not to cut into the underlying layers. Use these cuts as leverage to peel back the jacket and then the wire braiding beneath, going back the same length as the connector
4. Place the connector onto the exposed length of wire
5. Attach the connector to the wire by applying pressure. Use a compression tool – for example, a pair of pliers – or a more specialist crimping tool. Crimping is only a modified form of compression, so the two methods are very similar. In both cases, insert the connector which has been placed over the cable into the tool and apply firm pressure. Finally, spray liquid electrical tape to any remaining exposed areas and allow this to dry

What are Micro Connectors?

Micro-coaxial connectors are made for the smallest cables – typically not exceeding 1.5cm in diameter and less than 6 GHz. Their small size makes them well suited for use in complex but physically small electronics such as mobile phones, GPS receivers, Wi-Fi routers, and PC equipment.