Variables to Consider When Choosing Coax Connectors

With literally thousands of coax connector designs to choose from in the marketplace, It can be an overwhelmingly daunting task deciding which connector is most suitable for your application. Lighthorse Technologies Inc has created a checklist of considerations to to help you decide which connectors are most applicable for your device.

1. Frequency of Operation

Frequency refers to the number of times a periodic action occurs in one second. The SI unit for measuring frequency is hertz. Coax connectors are grouped into families,types, or series. Each connector series is designed to operate within a specific frequency range. SMA connectors are ideal for many applications due to their broad operating frequency range of 0-18 Ghz. Refer to our Coax connector specifications sheet for frequency ranges of many common coax Connectors.

2. Characteristic Impedance

Impedance matching is a necessity when choosing the right coax connector. The SI unit for measuring impedance is Ohms. Most connectors operate between 50-95 ohms. Coax connectors used in audio and video applications such as BNC and F connectors usually operate at 75 ohms. Most 2400 Mhz applications operate at 50 ohms.

3. Insertion Loss

Insertion loss, expressed as a ratio in dB relative to the transmitted signal power, refers to the amount of signal power lost in transmission due to device interference. Insertion loss is commonly referred to as attenuation. The farther the signal must travel , the higher the attenuation. Many factors affect insertion loss including coax cable type and length. The main purpose of a coax connector is to minimize attenuation.

If the power transmitted by the source is PT and the power received by the load is PR, then the insertion loss in dB is given by

4. Power Handling

Most coax connectors used in the telecommunications industry safely operate up to 500 volts. Usually the larger the connector, the higher the power handling. For instance, N Type connectors can handle up to 2,700 volts. Refer to our coax connector specifications sheet for more information.

5. Gender

Regarding coax connectors, plugs are typically referred to as "male", are threaded on the inside & usually house a contact pin. Jacks are usually referred to as "female", contain threads on the outside & usually do not house the contact pin. Not all RF connectors are threaded. MCX connectors utilize a snap on mating mechanism.

• See also Reverse Polarity Connectors

6. Form Factor

Since the development of the first PL-259 UHF connector in the 1930's, Coax connectors have become increasingly smaller in size. The micro-miniature IPX connector from Lighthorse Technologies Inc. boasts a profile of only 2.5mm! Keep in mind however, there is a trade-off between size and power handling.

7. Durability

Many factors influence the ruggedness of a coax connector. How often will the connector be connected and disconnected? Most coax connectors are rated up to 500 mating cycles. Is the connector for outdoor or indoor use? At what temperatures will the connector be subjected to?

8. Environmental Considerations

The main factors to keep in mind concerning durability involve environmental considerations. Mil-Spec coax connectors undergo testing standards which simulate environmental conditions such as vibration and corrosion. These standards are usually expressed in MIL-STD-XXX format.

9. Coupling Style

The mating mechanism associated with a coax connector is another one of the factors concerning durability. The common threaded interface provides a secure connection for SMA connectors, but is not convenient for frequent disconnects as the bayonet locking feature of the BNC connector. Snap on mating is becoming more common in more space critical applications. Refer to our coax connector specifications sheet for more information.

10. Cost

Most often, despite finding the perfect Coax connector for your RF application, the final decision comes down to budget. SMC and SMB connectors are on the higher end of the price spectrum , while F and BNC connectors remain on the lower end.

These considerations serve as a reference summary of top considerations when choosing a coax connector for your application. Trade off's often occur between these factors. However, each project demands its own set of requirements. Decide what works best for YOUR project. Please do not hesitate to contact Lighthorse Technologies Inc by phone at 1-800-443-3446 or by email at sales@rfconnector.com with any questions you may have about choosing coax connectors for your application.