When attempting to transmit radio signals through cable, you need specific cabling. You’ll need to find a coaxial cable, which has shields needed to protect radio signals as they travel. These cables are familiar to consumers in the form of Wi-Fi and cable TV cabling, but are specialized for RF capacity. Since these cables are specially designed, they need specific connectors. Most applications can use either soldered or solderless RF connectors. Here are a few of the most common connections you’ll find.
Sub-Miniature A Connector
These connectors are the most common for consumer-grade RF projects. Almost anyone who has internet service has had some interactions with these. They have a 50-ohm impedance and are able to conduct frequencies up to 17 GHz. You’ll find these connectors on coaxial cables used for cell signals, GPS and other familiar channels.
Bayonet Neill-Concelman Connector
The BNC connector is largely out of use in large applications like studio television, and has also been phased out of CCTV cameras. If used for frequencies over 4 GHz, it can actually become a radiator, so you’ll only need it for applications under 3 GHz like amateur radio projects or for testing other equipment.
This is the smallest connector you’ll find with most suppliers. The connection port is at a 90 degree angle from the cable, allowing it to function in applications where the device is small and flat. Wi-Fi cards are an example of U.FL usage.
It’s important to note that because female U.FL connectors use the connection pressure to remain secure through a “snap” or “pop” connection, they can wear out after just a few uses and must be replaced. Although this does provide tight contact, it reduces the life of the part. These are not ideal for a port you intend on connecting and disconnecting multiple times.