Coaxial Connector Types:
- 2.4 mm Coaxial Connectors
- BNC Connectors
- Blind Mate Connectors
- C Connectors
- CATV Indoor/Outdoor Taps
- Coaxial Snap-Lock Connectors
- Decoupled BNC and TNC Connectors
- F Series, G Series Connectors
 Micro-Miniature Connectors- Miniature Threaded Connectors
- N Coaxial Connectors
- OSMT Surface Mount Coax
- SHV Connectors
- SMA Connectors
- SMB Connectors
- SMC Connectors
- Series MCX (OSX) Microminiature
- Series MMCX Connectors
- Switching Coax Connectors
- TNC Connectors
- Twin BNC Connectors
- Twin Threaded Connectors
- Twinax and Triax Connectors
- UHF and Miniature UHF Connectors
Introduction to coaxial cables
Coaxial cable is a cable type used to carry radio signals, video signals, measurement
signals and data signals. Coaxial cables exists because we can't run a open-wire line near metallic objects or bury it. We trade signal loss for convenience and flexibility. Coaxial cable
consists of an insulated center conductor which is covered with a shield. The signal is carried between the cable shield and the center conductor. This arrangement give quite good
shielding against noise from outside cable, keeps the signal well inside the cable and keeps cable characteristics stable.
Coaxial cables and systems connected to them are not ideal. There is always some signal radiating from coaxial cable. More shield coverage means less radiation of energy.
Coaxial cables are typically characterized with the impedance and cable loss. The length has nothing to do with a coaxial cable impedance. Characteristic impedance is determined
by the size and spacing of the conductors and the type of dielectric used between them. For ordinary coaxial cable used at reasonable frequency, the characteristic impedance depends
on the dimensions of the inner and outer conductors. The characteristic impedance of a cable (Zo) is determined by the formula 138 log b/a, where b represents the inside diameter
of the outer conductor i.e. shield or braid, and a represents the outside diameter of the inner conductor. Most common coaxial cable impedances in use in various applications are 50 ohms and 75
ohms. 50 ohms cable is used in radio transmitter antenna connections, many measurement devices and in data communications (Ethernet). 75 ohms coaxial cable is used to carry
video signals, TV antenna signals and digital audio signals. There are also other impedances in use in some special applications (for example 93 ohms). It is possible to build cables at
other impedances, but those mentioned earlier are the standard ones that are easy to get. Here is a quick overview of common coaxial cable impedances and their main uses: 50 ohms:
50 ohms coaxial cable is very widely used with radio transmitter applications. It is used here
because it matches nicely to many common transmitter antenna types, can quite easily handle high transmitter power and is traditionally used in this type of applications. 60 Ohms:
Europe chose 60 ohms for radio applications around 1950s. It was used in both transmitting
applications and antenna networks. The use of this cable has been pretty much phased out, and nowadays RF system in Europe use either 50 ohms or 75 ohms cable depending on the application. 75 ohms:
The characteristic impedance 75 ohms is an international standard, based on optimizing the
design of long distance coaxial cables. 75 ohms video cable is the coaxial cable type widely used in video, audio and telecommunications applications 93 Ohms:
This is not much used nowadays. 93 ohms was once used for short runs such as the connection between computers and their monitors because of low capacitance per foot
which would reduce the loading on circuits and allow longer cable runs. In addition this was used in some digital communication systems (IBM 3270 terminal networks) and some |
