RF connector identification guide

The connectors you will encounter

Amateur radio uses a surprisingly small number of RF connector types, but the variations within those types — especially SMA gender — cause constant confusion. This guide identifies each connector by sight and explains where each is used.

SO-239 / PL-259 (UHF connector)

The standard amateur radio connector. The SO-239 is the female chassis-mount connector found on virtually every HF transceiver, amplifier, antenna tuner, and SWR meter. The PL-259 is the male cable-end connector that goes on your coax. Despite being called a "UHF connector," it was designed in the 1930s and is actually mediocre above VHF frequencies. The amateur radio community uses it because we always have.

Where you will find it: Every HF transceiver. Most VHF/UHF base and mobile radios. Most HF antennas. Amplifiers. Tuners. SWR meters. Virtually everything in a base station.

Limitations: The SO-239/PL-259 is not weatherproof without additional sealing. Impedance is not constant across frequencies. Performance degrades above 300 MHz. For 70cm and above, N-type is superior.

SMA connectors

Small connectors used on HTs and SDR equipment. SMA connectors come in male and female versions, and amateur radio manufacturers use BOTH orientations on their radios, which causes endless confusion.

SMA-Male on the radio (radio has the center pin, antenna is SMA-Female): Baofeng, Wouxun, BTECH, TYT, AnyTone, Retevis, TIDRADIO, Quansheng, Radtel, Radioddity. Most Chinese HTs, which follow commercial/Motorola practice.

SMA-Female on the radio (antenna has the pin, buy an SMA-Male antenna): Yaesu, Icom, Kenwood, and Alinco amateur HTs.

How to remember: If your radio is a Chinese brand, the radio has the pin — buy SMA-Female antennas. If your radio is Yaesu, Icom, Kenwood, or Alinco, buy SMA-Male antennas. When in doubt, look at the radio: a pin sticking up means the radio is SMA-Male and needs an SMA-Female antenna.

The exceptions (check before you order): Yaesu reversed its convention on the FT-25R/FT-4XR/FT-65R line — those have the pin on the radio and take SMA-Female antennas, so FT-60R antennas won't fit. Wouxun splits by product line: ham models (KG-UV6D/9D/9P) take SMA-Male antennas, GMRS models (KG-805G/905G/935G) take SMA-Female. Radioddity's GM-30 takes SMA-Male antennas but the GM-30 Pro/Plus take SMA-Female. Yaesu's own FT-65R manual calls the supplied antenna "SMA male" — it is naming the thread, not the pin, which is the opposite of how everyone else labels SMA gender.

Buying caution: many antenna listings say "fits Kenwood" because Kenwood's commercial TK-series takes SMA-Female antennas like the Chinese HTs do. Kenwood amateur HTs (TH-D75, TH-F6A) take SMA-Male antennas.

BNC connectors

A bayonet-lock connector used on older HTs (pre-SMA era), some portable transceivers (Elecraft KX2, KX3, Yaesu FT-817/818), and test equipment (NanoVNA, oscilloscopes). BNC is a twist-lock connector that is faster to connect and disconnect than SMA.

Where you will find it: Elecraft portables. Yaesu FT-817/818. QRP Labs QDX/QMX. Older Icom/Kenwood HTs (pre-1995). Test equipment. SDR dongles (some).

N-type connectors

The superior VHF/UHF connector. N-type has constant impedance across a wide frequency range and is weatherproof when properly installed. Used on VHF/UHF base antennas (70cm port on multiband radios), commercial equipment, and high-performance installations.

Where you will find it: 70cm antenna ports on IC-9700, IC-910H, FT-736R. Commercial repeater equipment. High-quality VHF/UHF coax assemblies. Cell tower equipment.

NMO connectors

The standard mobile antenna mounting connector. NMO (New Motorola) is a through-hole mounting system where the connector is permanently installed in the vehicle roof or trunk. The antenna screws onto the NMO base. Public safety and commercial vehicles use NMO exclusively.

Where you will find it: Professional mobile installations. Larsen and Hy-Gain mobile antennas. NMO mount kits. The antenna screws on from the outside; the coax connector is underneath.

3/8-24 thread

The standard HF mobile antenna connector. Hustler resonators, Hamsticks, and many HF mobile antennas use the 3/8-24 threaded mounting system. The antenna screws onto a mast that mounts to the vehicle.

Where you will find it: Hustler mobile resonators. MFJ Hamsticks. Tarheel screwdriver antennas. Wolf River Coils. HF mobile mast mounts.

Anderson Powerpole connectors

The standard DC power connector for amateur radio. ARES and RACES standardized on Anderson Powerpole for DC power distribution because they are genderless (both sides are identical), color-coded, and rated for high current. Not an RF connector, but every ham encounters them.

Where you will find it: Power supply outputs (Powerwerx). DC power distribution panels. ARES/RACES go-kits. Portable station power connections.