PL-259 connector for RG8/AW and RG-213 coax cable
Gold-plated brass to better withstand the elements and to minimize traditional connector-borne signal loss
Since the majority of the signal travels on the surface of the connector, with gold's very high conductivity, these connectors ensure the best possible connectivity



The UHF connector is a coaxial RF connector that is used in low cost applications for frequencies in the HF and the bottom end of the VHF spectrum. Although it does not offer a particularly high level of performance, this RF connector has a rugged construction, and is satisfactory for many applications where cost may be an issue.

Originally designed to cover frequencies in the range 0.6 to 300 MHz, UHF connectors were aimed at use within the radio industry. However, in view of the fact that the frequency of operation for the connector extended to 300MHz - the bottom of the UHF band of frequencies - it was given the name of UHF connector.

The UHF plug is referred to as a PL-259 coaxial connector, and the socket as an SO-239 connector. These numbers arise from the original military numbers given to the UHF connectors.

These coaxial connectors have a threaded coupling which prevents them from being removed accidentally. It also enables them to be tightened sufficiently to enable a good low resistance connection to be made between the two halves.

The basic RF connector (PL-259) is has a relatively large threaded hole through which the coax cable enters. This is suitable for large, low loss cable, and also makes the connector suitable for relatively high power applications.
Where smaller cable is to be used a reducer sleeve can be used. This reducer sleeve screws into the threaded coax cable entry hole may be used to make the cable entry diameter suit the size of the cable being used.

The drawback of the UHF connector is that it has a non-constant impedance. This limits their use to frequencies of up to 300 MHz -- suitable for many applications, provided that the frequencies do not rise.

Soldering PL-259 connectors is not always easy. Start by stripping back about 1.5 inches (35mm) of the outer coating or sheath of the cable, taking care not to cut too deeply and score any of the fibers of the conductive shielding braid. Leave around 0.5 inch (13mm) of the copper braid or shielding in place and then remove about 0.5 inch (13mm) of the plastic core.
Tin the exposed central copper core, if it is not tinned already. To do this, heat the core with the soldering iron and apply a thin even coating of solder to it. Take care not to keep the soldering iron on the conductor for too long, otherwise the dielectric insulator between the outer and inner conductors of the coax can melt.
Once the cable has cooled, slide the inner part of the PL-259 plug over the cable with a screwing action until the copper core appears at the end of the center pin. The trimmed shield will have become trapped between the core and the inside of the PL-259. The outer covering of the coax cable will ensure a snug fit and any protruding shielding should be removed with the sharp knife.