Ham radio is a hobby that you can enjoy for the rest of your life. It’s also a great way to stay in touch with friends and family when there are no cell towers nearby. One of the most important pieces of equipment for ham radio enthusiasts is an antenna connector. An antenna connector attaches to the end of an antenna cable and matches up with another connector on your transceiver or other piece of ham radio equipment, such as a power supply. What is the difference between a PL-259 and an SO-239 connector? A complete guide will describe what they all look like and how they work so you can choose which ones best suit your needs.
Main Ham radio Antenna Connector types
A tiny component like an antenna connection might cause much confusion when attempting to figure out what you’ll need. Each connector type has its own advantages and disadvantages, but there are a few that stand out as the most common choices for hams. All types of these connectors we will discuss today.
PL-259 and SO-239 connectors
PL-259 and SO-239 are most common antenna connectors which could found on most mobile radios and HF rigs. Typically, the SO-239 (UHF Female/UHF Jack) is installed on the radio, and the PL-259 (UHF Male/UHF Plug) is installed on the cable. The two “mate” and are collectively known as a UHF Connection.
By design, these connectors reliably carry signals at frequencies up to 100 MHz. The coupling shell has a 5⁄8 inch 24 tpi UNEF standard thread and an approximately 0.156 inch-diameter (4 mm) pin and socket for the inner conductor. Despite the name, the UHF connector is rarely used in commercial applications for today’s UHF frequencies, as the non-constant surge impedance creates measurable electrical signal reflections above 100 MHz.
UHF connectors can handle peak power levels well over one kilowatt based on the voltage rating of 500 volts peak while manufacturers typically test UHF jumpers in the 3-5 kV range. In practice, voltage limit is set by the air gap between center and shield.
BNC (Bayonet Neill Concelman)
BNC is widely used for VHF/UHF ham radio mobile and base station radios. The female version features three holes while male connectors have five (the center pin being slightly larger than the four outer pins). Males will also feature either right or left hand threading to prevent incorrect installation of different genders on each side. BNC connectors are made to match the impedance of cable at either 50 ohms or 75 ohms. They are usually applied for frequencies below 4 GHz and voltages below 500 volts.
SMA (SubMiniature Version A)
This is a very small antenna connector that was originally introduced in the 1960s and it has been widely adopted as an amateur radio standard. It’s used on most handheld VHF/UHF radios such as Baofeng, Wouxun, etc., but also appears on larger equipment like mobile two meter transceivers. This connector features only 50 ohms of impedance and a 1/4-inch-36-thread-type coupling mechanism. It offers excellent performance from 0 to 18 GHz.
N-connectors are used by some ham radio VHF and UHF transceivers. It’s a threaded connector, like SO-239, but not as common for use on mobile radios. The average power rating is determined by overheating of the centre contact due to resistive insertion loss, and thus is a function of frequency. Typical makers’ curves for a new clean connector with a perfect load give limits of 5000 watt at 20 MHz and 500 watt at 2 GHz. It’s possible that the N-connector is labeled only with a model number, which may make identifying it in a mixed impedence scenario difficult.
MMCX (Micro Miniature Coaxial)
MMCX looks similar in appearance to the SMA but has an inner diameter that’s much larger at about two millimeters and it allows for higher frequencies because it doesn’t have a protruding center pin. MMCX is used for characteristic impedance 50 ohms for frequency range up to 6 GHz.
The big advantage these connectors offer over standard BNC or SO-239 types is they don’t use threaded fittings which means no extra accessories are required when making connections between radio equipment. They do require special adapters though so make sure you get those if needed before purchasing any antennas.
Make a best choice!
Whether you are looking for a connector to use with your antenna or some other piece of equipment, the tips we’ve discussed today should help simplify this process. There is no one ideal type of connector that will work best in all situations, but it helps to know what your options are before making up your mind about which one is right for you. We can’t wait to hear from our readers and find out how these connectors have helped them!