Adapters - UHF

UHF RF Adapters

This collection contains RF coaxial adapters having a UHF-series connector on at least one side. UHF connectors are widely used in amateur radio, CB radio, commercial communications equipment, antennas, coaxial cables, test equipment, and many other RF applications.

The most familiar UHF-series connectors are the PL-259 male plug and SO-239 female receptacle. Because these designations are commonly used interchangeably with “UHF male” and “UHF female,” you may see both forms of terminology when identifying equipment, cables, and adapters.

UHF adapters allow equipment using PL-259/SO-239 connections to interface with other RF connector families such as BNC, TNC, N, SMA, and others. UHF-to-UHF adapters may also be used to change gender, orientation, or connection configuration.

Selecting the Correct UHF Adapter

When choosing an RF adapter, identify the connector required at both ends:

Equipment connector → Required adapter end → Connector needed on the opposite end

For example, equipment having an SO-239 female connector normally requires a mating PL-259/UHF male connection on that end of the adapter.

Always check the complete adapter description and photographs before ordering. Two adapters may contain the same connector families but have different genders or configurations.

Important — Standard 5/8"-24 vs. Metric UHF-Style Threads

Unless specifically stated otherwise in an individual product description, the UHF connectors and adapters offered here use the standard PL-259/SO-239 5/8"-24 UNEF interface.

Some China-made and other imported UHF-style connectors use a metric thread instead of the standard 5/8"-24 UNEF thread. A commonly encountered version is M16×1, having a nominal 16 mm diameter and 1 mm thread pitch. Variations also exist among imported connectors, so appearance alone is not a reliable way to determine the thread specification.

These connectors can look very similar to standard PL-259/SO-239 connectors, but they should not be assumed to be interchangeable. Attempting to mate mismatched threads can result in poor fit, damaged or stripped threads, and an unreliable mechanical or RF connection.

An additional source of confusion is that some CB radios, radios, antenna mounts, and other equipment may themselves use the metric-style interface. A connector threading onto one of these devices successfully does not necessarily prove that it has the standard 5/8"-24 UHF thread.

If there is any doubt, verify the thread specification with the equipment or connector manufacturer, or measure the connector using an appropriate thread gauge or caliper. Do not force a connector that does not thread smoothly.

Unless specifically noted otherwise, W5SWL UHF adapters in this collection use the standard 5/8"-24 PL-259/SO-239 thread specification.

For additional information about identifying these two thread types, see our FAQ:

A Normal PL-259/SO-239 Thread vs. the China-Made PL-259 Thread

UHF Connector Frequency Considerations

Despite the historical name “UHF,” the UHF connector is an older, non-constant-impedance connector design. It remains extremely useful and popular for HF and many VHF radio applications, but it is generally not the preferred connector when precise impedance control and low reflection are important at higher RF frequencies.

When adapting between UHF and a precision 50-ohm connector such as N, BNC, TNC, or SMA, remember that the performance of the complete connection is limited by the characteristics of all connectors and adapters in the signal path.

Keep Adapter Chains to a Minimum

RF adapters are extremely useful for connecting otherwise incompatible equipment, but every additional adapter adds another mechanical and electrical interface. When practical, use the fewest adapters necessary, particularly at higher frequencies or in low-loss RF systems.

If you are uncertain which UHF, PL-259, or SO-239 adapter you need, identify the connector on your equipment and the connector you need to connect to it before selecting the adapter.