A Complete Guide to RF Adapters and RF Connectors

Radiofrequency (RF) connectors and adapters are passive electrical components intended to operate at radio frequencies in the multi-megahertz range. They have a wide range of uses, including domestic, professional, industrial, and military applications, and can be used in conjunction with coaxial cable, antennas, radios, test and measurement equipment, and surge protectors, to name just a few examples.

Multiple different types of RF connectors and adapters are available, and as a result, they can be classified in several different ways. These include type, size, impedance, and termination, although they are usually distinguished by their gender and polarity.

RF coaxial connectors can be installed in one of two different ways.

The first installation method involves simply crimping the connector onto the cable. Alternatively, the connector can be screwed onto the end of the cable. Both installation techniques are commonly used and relatively simple to perform.

Another difference refers to the centre pin. Depending on your preferred installation method, this can be either soldered or crimped. Soldering the centre pin is typically the standard approach, but crimping is a possible alternative.

The following steps provide a handy breakdown describing how to connect an RF adapter to coaxial cable. Remember, you should always make sure to familiarise yourself with the manufacturer’s instructions before beginning the task.

• Decide which method of connection you want to use (crimping or soldering)
• Strip the cable back, as per the manufacturer’s guidelines
• Either crimp or solder the centre pin, depending on the connection type you have chosen
• Attach the outer to complete the process

While this is not a complex process, it is still important to perform it correctly to avoid causing damage to the components. Once you have familiarised yourself with the process and are confident to proceed, following the steps above should help you to complete the task with ease.

There are also three different coupling mechanisms for installation. These are:

• Screwed Coupling – this consists of thread and coupling nut with a maximum torque setting for coupling nut captivation
• Bayonet Coupling – this type of connection is important for sturdy mechanism and faster mounting
• Snap-On Coupling – this is a quick snap-in connection and disengagement mechanism suitable for most small connectors

Identifying RF Connector Types

This chart is designed to clearly show some of the main RF connector types:

Microminiature	Subminiature	Miniature	Standard	Large
BMMA	BMA	BNC	C	GHV
MCX	SMA	TRB	HN	LC
MMCX	SMK	MHV	N
SMP	SMB	TNC	SC
SMPM	SMC
MHF	TPS

In addition to the different types of RF connectors as explained above, these devices are also available to suit varying frequencies.

The chart below provides a concise overview:

Frequency	Connector Type/s
50 MHz	MHV
500 MHz	TRB
1 GHz	GHV, LC
4 GHz	BNC, HN, SMB
6 GHz	MCX, MMCX, MHF
10 GHz	SMC, TPS
11 GHz	C, N, SC, TNC
18 GHz	SMA
22 GHz	BMA
28 GHz	BMMA
40 GHz	SMK, SMP
65 GHz	SMPM

RF adapters come in a range of sizes to suit different applications and connector sizes. They are typically categorised by type, as seen in the RF connector types chart above, yet these types also refer to the size of the device.

RF adapter sizes are typically available in both metric and imperial measurements, but it is also worth noting that the physical sizes of RF connectors are generally marked in imperial sizes. This is because many leading brands and manufacturers for these components are based in the USA so the connectors were designed and developed using imperial sizes. However, if you need to know the size of a component in metric measurements, it is easy enough to do a standard imperial to metric size conversion to ensure you select the right sized connector for your application.

RF adapters can be used in a wide variety of applications, including domestic, commercial, professional, and industrial environments. In short, RF adapters can be used wherever there is a need to make a connection using a coaxial cable.

In addition, adapters can also convert from one type of connector to another. This could include use with legacy machinery, for example. This makes these adapters highly versatile and useful devices in a wide range of different applications.

It is also worth noting that there is no universal connector. This is because specialised connectors are required for particularly high-frequency applications. As a result, RF adapters are also useful to enable test equipment to be used which generally feature BNC connectors.

The terms RF and coaxial are often used interchangeably, but it is important to note the distinction between the two.

In simple terms, RF is the signals which are transferred through shielded cables while coaxial typically refers to the cable itself. RF signals are often transmitted via coaxial cable, and it is also possible for coaxial cable to feature RF receivers and transmitters at the ends, too. Coaxial cables are sometimes called RF cables due to this, yet it is a common misconception that RF and coaxial mean the same thing.

Many RF connectors can be used with coaxial cable to provide highly-screened connections. This means that they are suitable for use with RF applications, certain test and measurement equipment, and environments where both RF and screening applications are required.