TheN connector(also,type-N connector) is a threaded, weatherproof, medium-sizeRF connectorused to joincoaxial cables.It was one of the first connectors capable of carryingmicrowave-frequency signals, and was invented in the 1940s byPaul NeillofBell Labs,after whom the connector is named.[2]
 Type N connector (male) | |||
| Type | RF coaxial connector | ||
|---|---|---|---|
| Production history | |||
| Designer | Paul Neill | ||
| Designed | 1940s | ||
| General specifications | |||
| Diameter |
Male:2.03 cm (0.80 in) Female:1.57 cm (0.62 in)[1][failed verification] (outer, typical) | ||
| Cable | Coaxial cable | ||
| Passband | 0–11 GHz, often up to 18 GHz | ||
Design
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The interface specifications for the N and many other connectors are referenced in MIL-STD-348.[3]Originally, the connector was designed to carry signals at frequencies up to 1GHzin military applications, but today's common Type N easily handles frequencies up to 11 GHz. More recent[when?]precision enhancements to the design by Julius Botka atHewlett-Packardhave pushed this to 18 GHz. Themaleconnector is hand-tightened (though versions with a hex nut are also available) and has an air gap between the center and outer conductors. The coupling has a5⁄8-24UNEF thread.Amphenolsuggests tightening to a torque of 15 inch-pounds (1.7 N⋅m),[2]while Andrew Corporation suggest 20 inch-pounds (2.3 N⋅m) for their hex nut variant. As torque limit depends only on thread quality and cleanliness, whereas the main operational requirement is good RF contact without significant steps or gaps, these values should be seen as indicative rather than critical.
Power rating
editThepeakpower rating of an N connector is determined by voltage breakdown/ionisation of the air near the center pin. Theaveragepower 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 (VSWR=1.0) give limits of ≈5000 W at 20 MHz and ≈500 W at 2 GHz.[4] This square root frequency derating law is expected from theskin depthdecreasing with frequency. At lower frequencies the same maker recommends an upper bound of ≈1000 V RMS. To achieve reliable operation in practice over an extended period, a safety factor of 5 or more is not uncommon, particularly when generic parts may be substituted, or the operating environment is likely to lead to eventual tarnishing of the contacts.
Impedance options
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The N connector follows MIL-STD-348, a standarddefined by the US military,and comes in 50 and 75ohmversions. The 50ohmversion is widely used in the infrastructure of land mobile, wireless data, paging and cellular systems. The 75ohmversion is primarily used in the infrastructure ofcable televisionsystems. Connecting these two different types of connectors to each other can lead to damage, and/or intermittent operation due to the difference in diameter of the center pin.[5]
Unfortunately, many type N connectors are not labeled, and it can be difficult to prevent this situation in a mixed impedance environment. The situation is further complicated by some makers of 75 ohm sockets designing them with enough spring yield to accept the larger 50 ohm pin without irreversible damage, while others do not. In general a 50 ohm socket is not damaged by a 75 ohm pin, but the loose fit means the contact quality is not guaranteed; this can cause poor or intermittent operation, with the thin 75 ohm male pin only barely mating with the larger 50 ohm socket in the female.
The 50ohmtype N connector is favored in microwave applications and microwave instrumentation, such as spectrum analyzers. 50 Ω N connectors are also commonly used onamateur radiodevices (e.g.,transceivers) operating inUHFbands.
Variations
editSnapN
editSnapNwas originally designed byRosenberger Hochfrequenztechnikin 2006 and is a quick locking replacement for the threaded interface of the widely applied Type N connector. Though part of the Quick Lock Formula Alliance (QLF), engineers at Rosenberger independently designed the SnapN in order to correct the performance problems of QLF’s version of the quick lock N connector, QN. This design achieves better electronic performance because, unlike the QN, this new version maintains the basic structural parameters of the original Type N in which the inner dimensions of the outer conductor are 7.00 mm, and the inner conductor’s outer dimensions are 3.04 mm. A male N-connector can plug into a female SnapN.[6]
Left-hand thread
editThe left-hand thread, or reverse thread, uses the same 5/8-24 UNEF thread size but threaded in the opposite direction. These are used for some wireless LAN systems.[7]
Reverse-polarity N
editThe reverse-polarity connectors use the same outer shell, but change the gender of the inner pin. These are used for some wireless LAN systems.[7]
HN
editTheHNconnector is slightly larger (3/4 "-20 thread) and is designed for high-voltage applications.[8]
Applications
editType N connectors find wide use in many lower frequency microwave systems, where ruggedness and/or low cost are needed. Manyspectrum analyzersuse such connectors for their inputs, and antennas which operate in the 0-11 GHz range often connect to a coaxial cable with type N connections.
N connectors were historically used with10BASE5"thicknet"Ethernet.SomeMedium Attachment Unitshad both male and female N connectors, allowing the MAU to come in between two N connector-capped thick coaxial cables for effective passthrough. However, MAU attachment to uninterrupted cables viavampire tapswas more typical.
See also
edit- SMA connector,SMB connector,SMC connector
- UHF connector(aka PL-259 Connector)
- Optical fiber connector
References
edit- ^"Radiall R191381000 datasheet"(PDF).
- ^abAmphenol,N type datasheet(PDF)
- ^RADIO FREQUENCY CONNECTOR INTERFACES FOR MIL-DTL-3643, MIL-DTL-3650, MIL-DTL-3655, MIL-DTL-25516, MIL-PRF-31031, MIL-PRF-39012, MIL-PRF-49142, MIL-PRF-55339, MIL-DTL-83517(B with change 3 ed.). US DOD. 2017-01-22.
- ^RF Coaxial connectors General catalogue(2017 ed.). Huber+Suhner. p. 369.
- ^Golio, Mike (2008).The RF and Microwave Handbook, Second Edition.CRC. pp. 8–7.ISBN978-0-8493-7217-9.
- ^"RF Coaxial Connectors".rosenberger.
- ^ab"WiFi and Broadband RF Coax Connectors Product".rfcoaxconnectors.Retrieved2018-05-30.
- ^"HN-Type Connectors - Connectors".amphenolrf.
