What is a TNC Connector?

By Amy Goetzman

Meet the Connector: TNC Connectors

A threaded variant of the BNC, this RF connector is favored for applications in which vibration or shock is present.

TNC connectors are a threaded version of the popular BNC, a circular radio frequency connector used to connect RF cables and devices. Its 7/16″-28 threads can be tightened to reinforce the connection, making it suitable for use in high-vibration and high-stress environments such as military applications, Test & Measurement systems, communication infrastructure, and industrial RF installations. The interface specifications are referenced in MIL-STD-348.

“The TNC provides a better connection than its BNC counterpart providing a higher performance and works up to 11GHz compared to 4GHz for standard BNC connectors. The threaded coupling also makes the TNC more water and dust resistant than BNC and many are available in IP67 or IP68 ratings for use in outdoor applications,” said Brian Tea, COAX Connectors.

The TNC connector was invented in the 1950s at Amphenol by Paul Neill and Carl Concelman to provide more secure alternative to the BNC. There are several theories behind the name TNC (and BNC before it). To some, it stands for Threaded Neill-Concelman, to honor Neill and Concelman. However, they did not invent the BNC, although Neill did develop the N connector, and the smaller type BN is called a Baby Neill by the U.S. Navy.

TNC Reverse Polarity IP68 Mated Crimp / Crimp Plug from COAX Connectors. 14-045-B3-DA is a straight crimp reverse polarity TNC plug with an IP68 rating with a white bronze plated body for use in outdoor antenna applications.

Configurations

Plug Types (Male): The TNC plug features a center pin (male contact) surrounded by an outer coupling nut with internal threads. Standard plug configurations include straight (inline) and right-angle variants. The right-angle plug routes the cable perpendicular to the mating axis, useful in space-constrained installations. Reverse-polarity (RP-TNC) plugs swap the gender of the center contact, placing a female socket in the plug body. This configuration is common in consumer Wi-Fi equipment to prevent non-certified antenna connections.

Receptacle Types (Female): TNC receptacles (jacks) present a female center contact (socket) and a threaded outer barrel. They are available as panel-mount, bulkhead, PCB edge-mount, and surface-mount variants. Bulkhead receptacles include a jam nut or flange for chassis mounting. PCB versions use through-hole or SMD termination for direct board integration.

Materials

The connector body is typically made of brass with nickel, silver, or gold plating to enhance corrosion resistance and reduce contact resistance. Center contacts are commonly made from beryllium copper or brass, gold-plated to ensure reliable low-resistance mating and longevity through repeated mate/unmate cycles. The dielectric insulator separating the center conductor from the outer body is fabricated from PTFE (polytetrafluoroethylene), chosen for its low dielectric loss, dimensional stability across temperature extremes, and chemical inertness.

Radiall’s TNC self-lock was designed in 2011 for airborne systems. The range includes cable plugs operating in the range DC-18 GHz/50 ohms.

Sealing Technology

TNC connectors are available in both standard and hermetic/weatherproof versions. Environmental sealing is achieved through captive O-rings seated in grooves on the mating interface, compressing upon full thread engagement to create an IP67-rated barrier against moisture and dust ingress. Some military-grade variants incorporate fluorosilicone or Buna-N O-rings for resistance to fuels and hydraulic fluids. Hermetically sealed versions use glass-to-metal seals at the center conductor feedthrough, providing a hermetic barrier suitable for pressurized or vacuum enclosures.

Technical Features

The TNC connector operates reliably from DC to 11 GHz, with precision-grade versions extending performance to 18 GHz. Its characteristic impedance is 50 Ω (75 Ω versions exist for video applications). The threaded coupling mechanism — typically a 7/16–28 UNEF thread — provides a secure, vibration-resistant connection. Maximum VSWR is typically ≤1.3:1 across the rated frequency range, with minimum RF leakage due to the fully shielded, continuous outer conductor design. Mating durability is rated at a minimum of 500 engagement cycles; ruggedized variants exceed that rating significantly.

Winchester Interconnect’s TNC and TNCA series threaded coaxial RF connectors deliver exceptional performance at higher frequencies, typically up to 11 GHz (with precision versions reaching 18 GHz), and in applications subject to high vibration or shock.

Markets and Applications

Military and Aerospace, Telecommunications and Wireless Infrastructure, Test & Measurement, Transportation, Automotive, Industrial, Medical

The TNC connector is more robust than the BNC and more compact than the N-type, making it one of the most broadly deployed RF connector families across both commercial and military applications.

Suppliers

COAX Connectors, Molex, Radiall, Rosenberger, TE Connectivity, Times Microwave Systems, Winchester Interconnect

Connector Configuration

Plug Types	Straight (inline), Right-Angle, Reverse-Polarity (RP-TNC), Bulkhead Plug, PCB Mount Plug
Receptacle Mounting Styles	Panel/Bulkhead (flange or jam nut), PCB Through-Hole, PCB Surface Mount (SMD), Edge Mount, Box Mount
Mating Cycles (rated)	500 minimum (standard); 1,000+ for ruggedized/military-grade variants
Locking Mechanism	Threaded coupling nut (positive locking via full thread engagement)
Thread	7/16-28 UNEF (Unified Extra Fine)
Keying / Anti-Mismating	No native keying on standard TNC; Reverse-Polarity (RP-TNC) center contact gender swap serves as a physical mismating deterrent; some mil-spec variants incorporate keyed interfaces
Weight	Approximately 5-10 g depending on body style, cable size, and material finish

Contact Specifications

Contact Count	2 (1 center conductor + 1 outer conductor/shield)
Contact Sizes / AWG	Center contact sized to accommodate RG-58 (AWG 20), RG-142 (AWG 18), RG-213 (AWG 13), and other common coaxial cable series; specific AWG compatibility varies by crimp or clamp configuration
Contact Pitch	N/A — single coaxial contact pair; no multi-contact pitch applicable
Contact Material	Center contact: Beryllium copper or brass; Outer contact/body: Brass
Contact Plating	Gold (Au) over nickel standard for center contact; Nickel or silver plating common on outer body; Gold plating thickness typically 0.75-1.27 um (30-50 uin)
Contact Gender	Standard TNC — Plug: male center pin, female outer shell; Receptacle: female center socket, male outer shell. RP-TNC — Plug: female center socket; Receptacle: male center pin
Termination Method	Crimp, solder (cup or turret), clamp (rear-release), and PCB solder pin; crimp most common for cable-mount applications
Contact Resistance	Center contact: <= 3 mOhm; Outer contact: <= 2 mOhm (per MIL-STD or manufacturer spec)
Current Rating per Contact	Typically 1-3 A continuous on center conductor (frequency and application dependent)
Voltage Rating	500 V RMS (standard); up to 1,000 V RMS for high-voltage variants
Dielectric Withstanding Voltage	1,000-1,500 V RMS (tested per MIL-STD-202 or IEC 60169)
Insulation Resistance	>= 5,000 MOhm at 500 V DC (minimum); typically >= 10,000 MOhm under standard conditions
Special Contact Types	Hermetically sealed center contacts (glass-to-metal seal); captive contact designs for blind-mate applications; silver-plated contacts for cryogenic or high-power RF use

Environmental & Mechanical Performance

IP Rating	IP67 (standard environmental versions); IP68 for submersible/mil-spec variants
Sealing Type	Interface O-ring seal (mating face); cable entry grommet or boot seal; hermetic glass-to-metal seal on sealed feedthrough variants
Seal Material	Buna-N (Nitrile) — general purpose; Fluorosilicone (FVMQ) — fuel/solvent resistance; EPDM — weathering/ozone resistance; PTFE — chemical inertness; Silicone — wide temperature range
Operating Pressure	Typically rated to 1 atm differential (standard); up to 3-5 atm for ruggedized/subsea variants
Proof Pressure	1.5x operating pressure (per MIL-STD testing); typically 15-75 psi proof pressure depending on variant
Immersion Depth Rating	IP67: 1 m for 30 minutes; IP68: up to 10 m continuous (variant dependent)
Operating Temperature Range	-65 deg C to +165 deg C (standard mil-spec per MIL-PRF-39012); -40 deg C to +85 deg C for commercial grades
Storage Temperature Range	-65 deg C to +200 deg C (mil-spec); -55 deg C to +125 deg C (commercial)
Humidity Resistance	Tested to 95-98% RH at 40 deg C for 96 hours minimum (per MIL-STD-202 Method 103); no degradation of insulation resistance or contact performance
Vibration Resistance	10-2,000 Hz, 15-20 g peak acceleration (per MIL-STD-202 Method 204); threaded coupling provides inherent vibration lock superior to bayonet-style connectors
Shock Resistance	50-100 g, 11 ms half-sine pulse (per MIL-STD-202 Method 213); ruggedized variants rated to 500 g sawtooth
Corrosion Resistance	48-500 hours salt fog exposure (per MIL-STD-202 Method 101 / ASTM B117); nickel and gold plating provide primary corrosion barrier
EMI/RFI Shielding	360 deg continuous outer conductor provides inherent coaxial shielding; shielding effectiveness typically >90 dB across operating frequency range
Ruggedization Level	Commercial, Industrial, and MIL-SPEC (MIL-PRF-39012 / MIL-DTL-55339) grades available; MIL-spec versions meet stringent environmental, mechanical, and electrical requirements for airborne, shipboard, and ground military platforms

Insulator & Overmold Materials

Plug Insulator Material	PTFE — standard dielectric insulator in virtually all TNC plug configurations, both commercial and MIL-PRF-39012 mil-spec; chosen for low dielectric loss (tan delta < 0.0002) and stability across the full -65 deg C to +165 deg C operating range
Receptacle Insulator Material	PTFE — used in panel-mount, bulkhead, and PCB-mount TNC receptacles; Glass-to-metal (ceramic/glass bead) seal — used in hermetically sealed TNC feedthrough receptacles for pressurized enclosures, avionics, and vacuum applications
Overmold / Backshell Material	TNC cable assemblies most commonly terminate without an overmold on the connector body itself, as the machined brass coupling nut provides inherent mechanical protection; where strain relief is applied: heat-shrink adhesive-lined polyolefin tubing is the most common field solution; polyurethane overmold is used on pre-made commercial assemblies for environmental sealing at the cable entry; aluminum alloy backshells are used on mil-spec TNC assemblies (e.g., MIL-DTL-55339) requiring EMI continuity and robust cable strain relief

Compliance, Electrical Performance & Qualification

RoHS / REACH Compliance	RoHS 3 (EU Directive 2015/863) compliant on commercial and most current mil-spec variants; REACH SVHC compliance declared by major manufacturers; exemptions may apply to specific military/aerospace variants with legacy finishes
Halogen Free	Standard TNC connectors are not inherently halogen-free due to PTFE insulator (fluoropolymer); halogen-free variants available on request using alternative dielectrics; PTFE is generally considered low-risk despite fluorine content as it is chemically inert and non-bioavailable
UL Flammability Rating	PTFE insulator: UL 94 V-0 (self-extinguishing); connector body materials (brass, nickel-plated) are non-combustible; overmold/backshell materials rated UL 94 V-0 or V-2 depending on polymer selection
Impedance	50 Ohm (standard); 75 Ohm versions available for video/CATV applications
VSWR	<= 1.3:1 at 0-11 GHz (standard); <= 1.15:1 for precision/low-reflection variants up to 18 GHz
Insertion Loss	<= 0.1 dB at 1 GHz; <= 0.3 dB at 11 GHz (typical per mated pair)
Data Rate / Bandwidth	DC to 11 GHz (standard commercial); DC to 18 GHz (precision grade); supports broadband RF, microwave, and high-speed digital signal transmission
EMI Filter Integrated	Not standard; TNC is a passive RF connector; filtered TNC variants (with integrated capacitive or LC filter elements) are available from specialist manufacturers for EMI suppression at feedthrough points
Qualification Test Standard	MIL-PRF-39012 (primary mil-spec for RF coaxial connectors); MIL-DTL-55339; IEC 60169-17 (international standard for TNC connectors); IEEE 287 for precision RF connector performance
Shock Test Standard	MIL-STD-202 Method 213; MIL-STD-810 Method 516 for platform-level shock qualification
Vibration Test Standard	MIL-STD-202 Method 204; MIL-STD-810 Method 514 for platform-level vibration qualification
Thermal Cycling Test	MIL-STD-202 Method 107 (-65 deg C to +165 deg C); IEC 60068-2-14; typically 10-100 cycles depending on qualification level
HALT / HASS Tested	Not universally required by standard TNC specifications; HALT and HASS applied by manufacturers of ruggedized/aerospace variants to validate design margins beyond standard qualification
Space Qualification	Select TNC variants qualified to NASA and ESA standards; must meet MIL-PRF-39012 as baseline plus additional screening for outgassing, radiation tolerance, and thermal vacuum performance
Outgassing (space)	PTFE insulator: inherently low outgassing; space-qualified TNC assemblies must meet NASA ASTM E595 outgassing requirements: Total Mass Loss (TML) <= 1.0%, Collected Volatile Condensable Materials (CVCM) <= 0.1%; adhesives, overmolds, and lubricants are primary outgassing concerns and must be individually screened