Coaxial cable

 

Coaxial cable


Coaxial cable definition -

Coaxial cables are the guided media that carnes the signal of upper frequency range compared to twisted pair cable. Coaxial cables also are called coax. (short form).


Coaxial cable is named "coaxial" because it includes one physical channel that carries the signal surrounded (after a layer of insulation) by another concentric physical channel, both running along the identical axis.


A coax cable, sometimes called a transmission line, provides an interference-free transmission path for high-frequency electrical signals.

Coaxial cable


Coax cables have concentric layers of electrical conductors and insulant. This construction ensures that signals are enclosed within the cable and prevents electrical noise from interfering with the signal. It also yields the name "coaxial," relating its two physical channels running along the identical axis.


The center layer could be a thin conductor, generally manufactured from copper. A dielectric layer, made of an building material with very well-defined electrical characteristics, surrounds the wire. A shield layer then surrounds the dielectric layer with metal foil or copper mesh. the entire assembly is wrapped in an insulating jacket. The outer metal shield layer of the line is usually grounded within the connectors at both ends to shield the signals, and as an area for stray interference signals to dissipate(disappear).



Types of Coaxial Cables

There are two types of coaxial cables:

Types of Coaxial cable


Baseband coaxial cable -


  • A baseband coax cable transmits one signal at a time at very high speed.
  • Baseband coax cable supports frequency range upto 4kHz.
  • Used for transmitting digital signals.
  • Baseband coaxial cables are 50 ohm cables.
  • The baseband co-axial cable was originally used for the Ethernet system that operates at 10 Mbps.



Broadband coaxial cable -


  • A broadband coax cable can transmit many simultaneous signals using different frequencies.
  • Broadband coax cable supports the frequency range above 4kHz.
  • Used for transmitting analog signals, so it must be used with a modem.
  • Baseband coaxial cables are 75 ohm cables.



Advantages of Coaxial Cables -

1. It will be used for both analog and digital transmission.

2. It offers higher bandwidth as compared to twisted pair cable and may span longer distances.

3. thanks to better shielding in transmission line, loss of signal or attenuation is a smaller amount.

4. Better shielding also offers good noise immunity.

5. it's relatively inexpensive as compared to optical fibers.

6. it's lower error rates as compared to twisted pair.

7. it's not as easy to tap as twisted pair because copper wire is contained in plastic jacket.



Disadvantages of Coaxial Cables -


1. it's usually costlier than twisted pair.

2. High maintenance cost.

3. It also has high attenuation, needs repeaters.



Applications of Co-axial Cables:

1. Analog telephone networks.

2. Digital telephone network.

3. Cable TV

4. Traditional Ethernet LANs

5. Digital transmission



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