A practical reference to RF coaxial connectors — the families, what each one is for, which cables and equipment they pair with, and how to choose (and fit) the right one.

Who this is for: anyone terminating, adapting or buying coaxial cable in Australia — installers fitting a UHF CB or a Cel-Fi repeater, IoT and network people wiring a 4G/5G router, radio technicians on a base station or a DAS, and anyone who has stood in front of a wall of connectors wondering which one fits. It sets out the connector families, what each is for, which cables and equipment they pair with, and the practical things — torque, adapters, weatherproofing, 50 vs 75 ohm — that decide whether a connection still works in five years. For crimp vs solder vs compression, see our companion piece on termination methods.

1. Why the connector matters

A coaxial cable is a carefully controlled 50-ohm (or 75-ohm) environment, and the connector's only job is to carry that environment through the joint without a step change. Done well, a connector can cost as little as a few hundredths of a decibel — the exact figure depends on the family, the frequency, the part and how well it was fitted. Done badly — wrong impedance, a poorly fitted cable, a joint left open to the weather, a plug tightened with pliers — it costs you one or more of these:

• Insertion loss — signal power turned into heat at the joint;
• Return loss / VSWR — power reflected back down the line, which a transmitter sees as a mismatch;
• Passive intermodulation (PIM) — the joint itself generates spurious signals. Rarely a concern on a single-channel CB installation, a real problem on cellular repeaters, DAS and any multi-carrier system where a receiver sits centimetres from a transmitter;
• Water ingress — the number-one cause of an antenna system that "slowly got worse". Corrosion inside a connector raises loss and PIM month by month;
• Mechanical failure — vibration loosening a bayonet, a snap-on pulled off, a thread stripped by over-tightening.

Choosing well means matching four things: the cable (each connector is made for a specific diameter and construction), the frequency (every family has a ceiling), the environment (indoor, outdoor, vehicle, vibration) and — the one people forget — what is already on the equipment. The socket on the radio, router or antenna decides the family; everything else follows from it.

2. The families at a glance

3. Three ways to couple

Almost every RF connector mates in one of three ways, and the coupling usually rules a family in or out before anything else is considered.

Threaded — you screw it together. Slowest to mate, most secure, and the only sensible choice on a mast, a roof rack or a bull bar. SMA, N, TNC, UHF, Mini-UHF, FME, 7/16 DIN and the screw version of 4.3-10 are all threaded.

Bayonet — a quarter turn locks pins into L-shaped slots. Fast on and off, good for a bench that gets rewired weekly, poor under sustained vibration. BNC is the bayonet connector.

Snap-on and push-pull — push to connect, pull to disconnect, retained by a spring detent. Fastest of all and the smallest, at the cost of retention: MCX, MMCX and U.FL are pure snap-on; QMA and the push-pull 4.3-10 add a positive lock that has to be released deliberately, which is why those two are trusted outdoors.

A vibration-prone outdoor installation wants threaded. A test setup that changes every day wants bayonet or snap-lock. A permanent, sheltered installation can use whatever fits the cable.

4. Large, high-power connectors

These are the connectors on cellular base stations, broadcast transmitters, distributed antenna systems and the trunk feeder cables that serve them. They are built around low loss, high power and low PIM, and they take the large corrugated cables — 1/2", 7/8", 1-1/4", 1-5/8" — as well as 400-series braided cable.

7/16 DIN

The workhorse of mobile-network sites for decades. The name is the geometry: a 7 mm centre conductor inside a 16 mm outer, which is what gives it its power handling and its excellent PIM performance. It is a 50-ohm, weatherproof, threaded connector that expects a torque wrench — about 25 to 30 N·m — and rewards it with a joint that lasts. Use it where the equipment already has it (legacy DAS, broadcast, combiners and filters) and on feeder from 1/2" Superflex upward. Browse 7/16 DIN connectors.

4.3-10

The newer, smaller low-PIM family that new cellular equipment and low-PIM antennas are shipping with, increasingly used alongside the 7/16 DIN infrastructure it complements rather than retires. A 4.3 mm pin in a 10 mm outer makes it about 40% smaller and considerably lighter, so more ports fit on a radio and more jumpers fit in a tray. Its clever part is that the electrical contact and the mechanical clamp are separate surfaces, so the makers specify the same low PIM largely independent of coupling torque — which is why it comes in three couplings that all give the same specified result: a screw version (5 N·m with a wrench), a hand-screw version (no tool) and a push-pull quick-lock. The interface is standardised in IEC 61169-54 and specified by its makers to 12 GHz; the cellular bands it was designed for all sit below 6 GHz. Connectors exist for everything from RG58 jumpers to 1-5/8" AVA7-50 feeder, and low-PIM adapters bridge it to 7/16 DIN on existing plant. Browse 4.3-10 connectors.

UHF — PL-259 and SO-239

The oldest connector in this guide and, despite the name, the one you should keep below about 300 MHz. "UHF" meant something different in the 1930s; the connector has no controlled impedance, so the mismatch grows with frequency. What it has instead is size, strength, tolerance of rough handling and eighty years of installed base. The plug is the PL-259, the socket the SO-239, and the pair remains the standard on HF and amateur equipment, VHF marine radios and — importantly for Australia — the back of most UHF CB mobiles. At 477 MHz it is past its best — a non-constant-impedance connector working well above the range it was designed for — but the radios, antennas and accessories are built around it, and on a short, well-made lead the penalty is a fraction of a decibel. Use it where the equipment provides it and keep the run short; where a radio or antenna offers an N or another proper 50-ohm interface, that is the better choice at UHF, and there is no case for replacing a serviceable factory SO-239. It fits RG58 (with a reducer), RG213 and LMR-195/CNT-195. Browse UHF connectors.

5. Medium, general-purpose connectors

The middle of the range: widely available, easy to terminate, and used across most RF work that is neither a base station nor a circuit board.

N (Type N)

Designed by Paul Neill at Bell Labs in the 1940s and still the most common connector on outdoor antennas, jumpers, combiners and test equipment. Threaded, weather-resistant, 50 ohm, usable to 11 GHz, and available for almost every cable you will meet: RG58 and RG213/214, 400-series braided cable (Pulse 400, CNT-400, LMR-400), 1/2" Superflex and the corrugated feeders. Field practice is firm hand-tight; makers quote roughly 1 to 1.7 N·m if you want the number. A standard N is weather-resistant, not waterproof: unless the maker rates the assembly as sealed, an N joint outdoors gets taped like any other. A 75-ohm N exists for broadcast; check before you mix. Browse N connectors.

BNC

The Bayonet Neill–Concelman, a late-1940s design that made the quarter-turn lock famous. It is the connector of the oscilloscope, the signal generator, the CCTV camera and the lab bench, used to about 4 GHz. It comes in 50-ohm and 75-ohm versions that mate mechanically but not electrically — a mixed pair shows up as return loss, not a broken connection — so label your 75-ohm video leads. A standard BNC is an indoor part: the bayonet holds against a pull, not against a year of wind, and it is not sealed. Sealed and IP-rated BNC variants exist — use one of those outdoors, or a family better suited to the job. Browse BNC connectors.

TNC

The Threaded Neill–Concelman is the BNC with a screw thread in place of the bayonet — same size, same internals, but rated to 11 GHz and happy outdoors and in vehicles. You will find it on GNSS antennas, older outdoor Wi-Fi and wireless-link radios and some telemetry equipment. Two variants exist to stop the wrong lead being plugged in: reverse-thread (left-hand thread) and reverse-gender (pin and socket swapped, the same idea as RP-SMA). Neither mates with a standard TNC, so read the label on the equipment. Browse TNC connectors.

Mini-UHF — sold as "MPL"

Introduced in the 1970s for mobile radios and early car phones, the Mini-UHF is a proper 50-ohm connector usable to 2.5 GHz, so it is a far better performer than the full-size UHF it is named after — and it is not compatible with it. Pulse label their range "MPL", which is what you will see on our shelves. It survives on commercial two-way mobiles in fleets and mining, where the antenna lead arrives as FME and an FME-to-MPL adaptor finishes the job. Browse MPL (Mini-UHF) connectors.

6. Small, precision connectors

For higher frequencies, thinner cables and equipment with many ports. These are the connectors on routers, modems, GNSS receivers and cellular radio units.

SMA

The SubMiniature version A is the connector of the 4G/5G era: on every industrial router's cellular and GNSS ports, on Cel-Fi GO units, on cellular and combination antennas, on test gear to 18 GHz. It is threaded, 50 ohm and small enough that people abuse it. Tighten it with fingers and a nudge from a small spanner, or a torque wrench set to about 0.45 to 0.56 N·m for the brass connectors common on antennas; pliers strip the thread and the pin. It fits RG174/316, RG58 and the HDF-195/LMR-195 low-loss cables most antenna leads are made of. Outdoors, an SMA joint needs the same taping as an N. Browse SMA connectors.

RP-SMA — reverse polarity

Physically an SMA with the pin and socket swapped: an RP-SMA "male" has the male thread but a socket where the pin should be. It was introduced for Wi-Fi equipment to discourage casual antenna swaps, and it stuck — the Wi-Fi ports on most routers and access points are RP-SMA while the cellular ports beside them are plain SMA. The two thread together as if they matched, then either make no connection (socket meets socket) or push pin against pin and damage both — never treat them as interchangeable. A Teltonika RUTX50, for instance, has four SMA ports for mobile, two RP-SMA for Wi-Fi and one SMA for GNSS, which is why a combination antenna with five SMA leads arrives with two SMA-to-RP-SMA adaptors in the box. Pulse call the RP parts "reverse gender" — SMA-104RG is the RP-SMA male for RG58 — and the adapter range has the SMA-to-RP-SMA pieces.

QMA

A snap-lock alternative to SMA for equipment with rows of ports: push to mate, press the sleeve to release, no thread to torque, and it rotates freely once locked so the cable can be dressed without twisting the joint. Rated to 6 GHz and used on cellular remote radio units and some outdoor equipment. It does not mate with SMA; an SMA-to-QMA adaptor does. Browse QMA connectors.

7. Miniature and board-level connectors

These trade robustness for size and live inside equipment or on very small modules.

MCX and MMCX

MCX (micro coaxial, 1980s) is a snap-on 50-ohm connector about 30% smaller than SMB, good to 6 GHz, common on GNSS receivers, USB tuners and compact modules. MMCX is its smaller sibling — about 2.4 mm across, same 6 GHz, with a lock-snap that lets the plug rotate 360° once mated so the cable does not strain the board. Both take RG174, RG178 and RG316. Browse MCX and MMCX connectors.

U.FL / IPEX / MHF

The tiny push-on connector on the module inside a router, a modem card or an IoT board. It is rated to 6 GHz and to a limited number of mating cycles (the makers quote figures in the tens), and it is meant to be connected once — to a short pigtail that ends in an SMA or RP-SMA bulkhead on the enclosure. That bulkhead is the connector you should be plugging and unplugging; the U.FL should never see daylight. If you are building an enclosure around a module, budget for the pigtail and bulkhead rather than routing the antenna lead to the board.

8. The mobile-equipment connector: FME

"For Mobile Equipment" is exactly what it says. The FME is a small, threaded 50-ohm connector, rated to about 2 GHz, whose whole reason for existing is diameter: an FME female on the end of an RG58 or RG174 lead is barely wider than the cable, so it will pass through the holes, grommets and pillar trims of a vehicle that no N or PL-259 would. Once the lead reaches the radio, an FME-male adaptor turns it into whatever the equipment wants — FME to SMA for a router or Cel-Fi, FME to N for a base antenna, FME to MPL for a commercial mobile, FME to PL-259 for a CB. One lead, every radio: the same routed cable serves whatever radio ends up in the dash, with only the adaptor changing. The convention matters: the female goes on the cable, the male on the adaptor. Browse FME connectors.

9. Choosing the right connector

Work through these in order and the answer usually falls out.

1. What socket is on the equipment? Radio, router, repeater, antenna: their sockets are fixed. Match them, and adapt only where two fixed sockets disagree.
2. What cable are you using? The connector has to fit the cable's outer diameter, braid and dielectric exactly — an "RG58" N connector will not crimp properly on RG213, and a 400-series connector will not seal on RG58. Every connector on our site names the cables it is made for.
3. What frequency? UHF connectors below 300 MHz; FME, Mini-UHF and MCX/MMCX to 2–6 GHz; N, TNC and 4.3-10 comfortably through every cellular band; SMA to 18 GHz.
4. What environment? Outdoors and on vehicles, threaded or positively locked (N, 4.3-10, 7/16 DIN, TNC, SMA, QMA), then taped. On a bench, whatever is quickest.
5. How will you terminate it? Crimp is fastest and most consistent with the right die; solder suits small quantities and repairs; clamp and compression styles suit field work without a crimper. The companion article covers the trade-offs, and cable preparation and crimp tools are in the store.

Browse the whole range by family in RF connectors, and the cables in coaxial cables, cable by the metre and ready-made jumpers.

10. Practicalities that decide whether it still works next year

Torque

Every threaded connector has a torque range, and both ends of it matter: too loose and the joint moves, arcs and lets water in; too tight and the thread or the pin is damaged. Torque varies by series, material, plating and maker — Amphenol, for one, quotes roughly 0.3–0.6 N·m for a brass SMA and about 0.8–1.1 N·m for a stainless one — so the figures here are typical examples, and the value printed for the exact connector you are fitting overrides them: SMA about 0.45–0.56 N·m for brass parts, N firm hand-tight or roughly 1–1.7 N·m, 4.3-10 screw type 5 N·m, 7/16 DIN 25–30 N·m. Hold the body of the connector, turn only the coupling nut, and never rotate the cable to do it: twisting the cable twists the centre pin in its contact.

Adapters

An adapter is a legitimate part of a system — the FME lead and the Cel-Fi kit above both depend on one — but it is also another pair of RF interfaces — another potential source of loss, mismatch, PIM and water ingress — and one more joint to seal. The rules of thumb: use one adapter, not a chain; put it at the equipment end where it stays dry; on cellular repeaters, DAS and anything with a receiver near a transmitter, use low-PIM adapters rather than general-purpose ones; and if you find yourself needing the same adapter on every job, order the cable with the right connector instead. The RF adapters collection covers the common conversions — SMA to N, FME to anything, 4.3-10 to 7/16 DIN, BNC to TNC, SMA to RP-SMA.

Weatherproofing

No connector in this guide is waterproof once mated unless it was designed and installed as a sealed system; where the maker rates an assembly as sealed or IP-rated, follow its instructions rather than taping over the seal. Outdoors, wrap every joint — antenna base, adapter, jumper, lightning arrester — with self-amalgamating tape stretched as you wind, overlapping half its width, then a layer of good PVC tape over it to protect the rubber from ultraviolet light. Form a drip loop in the cable below the joint so water runs away from it, not into it. A roll of self-amalgamating tape is the cheapest insurance on the job.

Gender, and how to read a description

"Male" has the centre pin and, on most threaded families, the coupling nut; "female" has the socket and the fixed thread. Reverse-polarity and reverse-gender parts swap the pin and socket but keep the outer body, which is why they are described by both words — "RP-SMA male" has a male body and a female contact. "Bulkhead" means a connector with a flange and nut to mount through a panel. "Plug" and "jack" describe the mating role — the plug is usually the cable-mounted, movable part and the jack the fixed part — while "male" and "female" describe the contacts; in most families the plug is male and the jack female, but the reverse-polarity parts show that the two pairs of words are not the same thing, so order by the maker's exact designation. Our product titles follow the maker's naming, so a "Pulse SMA-104RG reverse gender SMA-male" is what most of the industry calls an RP-SMA male.

11. 50 ohm and 75 ohm

Almost everything in two-way radio, cellular, Wi-Fi, GNSS and professional RF is 50 ohm. Television, satellite, CCTV and video distribution are mostly 75 ohm, and so are their cables: RG59 and RG6 are 75-ohm cables, and the F connector is a 75-ohm connector. Families such as N and BNC come in both impedances, so the shape of a connector tells you nothing — check the equipment and cable specification. The two worlds mate more easily than they should — a 50-ohm BNC bayonets onto a 75-ohm BNC socket, a 50-ohm N onto a 75-ohm N, and RG6 looks a lot like a 50-ohm cable — and the result is a mismatch that shows up as return loss and, on a transmitter, as reflected power. Check the impedance printed on the cable jacket before you fit a connector, and keep the video leads out of the radio drawer.

12. Getting help

If you are not sure which connector you need, or you need a specific combination of cable, connector and termination, tell us what is on both ends and how long the run is and we will spec it. We carry the major RF connector families across crimp, solder and clamp terminations, the matching cables, adapters and the tools to terminate them, and ready-made jumpers in the common lengths. Request a quote or call 1300 168 777. Business customers can open a trade account for project pricing and invoice terms.

Interface ratings are drawn from the connector standards and the published data of Huber+Suhner, Rosenberger, CommScope, Pulse and Amphenol as at September 2026; torque figures are typical values and the maker's printed figure takes precedence. Equipment port details are from the manufacturers' current datasheets (Teltonika RUTX50; Nextivity Cel-Fi GO). This article is general guidance, not a substitute for the installation instructions supplied with your equipment.

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Adaptors Cable Connectors RF Connectors User Guide

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