When selecting an RF connector, the interface type is only one part of the decision. Factors such as cable diameter, center conductor size, dielectric construction, shielding, impedance, and termination style all need to be considered to ensure a reliable cable assembly. The compatibility chart below provides a quick reference for matching common RF connectors with widely used coaxial cables, including RG174, RG316, RG58, RG6, and LMR series cables.
Why Fit Matters
The connector interface tells you what it can mate with, but it does not guarantee that it will fit a specific cable. Connectors such as SMA, BNC, TNC, and N Type may use the same mating interface, yet the cable entry, center contact, crimp ferrule, and rear body can vary depending on the coaxial cable they are designed for. Because of this, connector selection should always be checked against the cable specification when building an RF cable assembly.
Several factors affect coax connector compatibility, including cable outer diameter, center conductor size, dielectric dimensions, shielding structure, impedance, and termination style. For instance, a connector designed for RG174 or RG316 is usually different from one intended for RG58 because the cable dimensions are not the same. Impedance must also match throughout the signal path. A 50 ohm cable should be paired with a 50 ohm connector, while a 75 ohm system requires 75 ohm components. The comparison chart below highlights these key fit considerations and shows which cable types are commonly supported by different connector families.
Start with Cable Size
Cable size is the first detail to check before choosing an RF connector. RG174 and RG316 are small coaxial cables with outside diameters close to 2.5 mm. RG58 and LMR195 are close to 5.0 mm. LMR240 is about 6.1 mm, and LMR400 is about 10.3 mm. These differences change the cable entry, center contact, crimp ferrule, rear body, and sleeve structure used in the RF cable assembly.
The same connector family can have several cable versions. An SMA connector for RG174 and an SMA connector for RG58 may share the same front interface, while the rear body and ferrule size are different. BNC connectors also exist for multiple RG cable sizes and impedance versions. A quick check of the coax cable outer diameter makes the compatibility chart easier to use.
Compatibility Chart
This RF connector compatibility chart gives a quick fit direction for common coaxial cables and connector families. The cable size shown below refers to typical outside diameter, so the final RF cable connector selection still needs to match the connector drawing, cable entry size, center contact, crimp ferrule, and assembly method.
| Cable Type | Typical Cable Size | Common Connector Options | Typical Use | Fit Note |
|---|---|---|---|---|
| RG174 | About 2.5 mm | SMA, SMB, MCX, MMCX, U.FL, FAKRA | GPS, WiFi, IoT modules, internal RF jumpers | Small cable entry and small crimp ferrule are needed |
| RG316 | About 2.5 mm | SMA, SMB, MCX, MMCX, BNC, TNC, FAKRA | Test leads, GPS cables, compact RF cable assembly designs | Often selected where a small coaxial cable needs better heat resistance |
| RG178 | About 1.8 mm | SMA, MCX, MMCX, U.FL, Mini SMB | Dense modules, small antennas, lightweight RF links | Very small center contact and ferrule dimensions need close checking |
| RG188 | About 2.8 mm | SMA, SMB, BNC, TNC, MCX | Compact test leads, high temperature RF leads, equipment wiring | Similar size group to small flexible coax, with different jacket and prep details |
| RG58 | About 5.0 mm | BNC, TNC, SMA, N Type, UHF | RF test cables, antenna jumpers, general coaxial jumper cable builds | Larger ferrule and rear body are required compared with RG174 or RG316 |
| RG59 | About 6.1 mm | BNC, F Type, 75 ohm N Type, TNC versions | Video, broadcast, CATV, 75 ohm coaxial cable systems | Connector impedance and cable entry size need to match the 75 ohm build |
| RG6 | About 6.9 mm | F Type, 75 ohm BNC, 75 ohm N Type | CATV, satellite, broadband, broadcast cable runs | Often used as a 75 ohm cable, with connector bodies different from RG58 types |
| RG142 | About 5.0 mm | SMA, TNC, N Type, BNC | Test cables, RF equipment leads, higher temperature cable assemblies | Same outside diameter group as RG58, with different dielectric and shield structure |
| RG400 | About 5.0 mm | SMA, TNC, N Type, BNC | Test leads, high temperature RF leads, equipment wiring | Double shield and PTFE dielectric need matching strip and crimp dimensions |
| LMR100 | About 2.8 mm | SMA, SMB, MCX, MMCX, TNC | Short low attenuation jumpers, compact wireless devices | Use a connector body made for the LMR100 cable group or the same cable size class |
| LMR195 | About 5.0 mm | SMA, BNC, TNC, N Type | Antenna jumpers, wireless equipment, telecom jumper cable assemblies | Similar outside diameter to RG58, with a different low attenuation cable structure |
| LMR240 | About 6.1 mm | N Type, TNC, SMA, BNC | Outdoor antennas, wireless systems, medium length RF cable runs | Connector body and crimp sleeve need to match the 240 cable group |
| LMR400 | About 10.3 mm | N Type, TNC, UHF | Longer antenna feeds, base station jumpers, low loss RF cable runs | Large cable entry, strong rear support, and proper strain relief are needed |
This coaxial cable connector chart is a fit guide, not a final assembly drawing. Many connector families have several versions for different cable diameters, impedance values, contact styles, and crimp tools. For custom RF cable assembly work, the cable type and connector part structure need to be checked together before sample production.
FAQ
Conclusion
A reliable RF connector and cable match starts with cable size, then moves to impedance, cable entry, crimp ferrule, and connector body structure. SMA, BNC, TNC, N Type, F Type, FAKRA, MCX, and MMCX connectors may all have different versions for different coaxial cables, so the final fit needs to match the cable drawing and assembly method before production.