PL-259 SO-239 UHF 90 Elbow Adapter

The UHF threaded RF coaxial connector is also called an Amphenol connector generally usable through the VHF and HF frequencies and can handle RF power levels over one kilowatt. At low frequencies the power handling is rather better than that of the similar sized N connector. The UHF connector is the most common connector in amateur radio applications up to 150 MHz. In the US, the silver-plated version with Teflon dielectric is used in UHF applications up to 450 MHz for the 70 cm band. The most popular cable plug and chassis-mount socket carry the old Signal Corps nomenclatures PL-259 (plug) and SO-239 (socket). The PL-259 can be used with large diameter coaxial cable, such as RG-8/U and RG-9/U, and the smaller diameter RG-58/U and RG-59/U with the UG-175/U and UG-176/U adapter sleeves. "PL-259" refers to one specific mechanical design, but the term is often used for any compatible UHF cable plug. The thread is 5⁄8 inch 24tpi UNEF standard. Other UHF connectors with a similar, metric, thread have been produced. The center conductor jack on the SO-239 will also accept a 4 mm banana plug.

UHF connectors have been replaced in many applications by designs that have a more uniform impedance over the length of the connector, such as the N connector and the BNC connector, but they are still widely used in amateur radio, citizens' band radio, and marine VHF radio where robustness and ease of use are more important than a small mismatch. The reasons for the popularity of the UHF connector is its ease of assembly. While crimp connectors exist, the solderable screw-on connector is more common because no expensive crimping tools are required. The connector is not suitable for outdoor applications by itself but can be made weather resistant with self adhesive silicone C-Tape.