+1 vote
How does a coaxial feeder attenuate signal frequencies ?
related to an answer for: Antenna used in satelite tv broadcasting
asked Dec 1, 2015 in Electro-Communication by ppk | 60 views

1 Answer

+2 votes

Attenuation (or loss) is a key specification of coaxial cables.The function of coaxial cable is to transfer radio frequency power from one point to another. In doing so, some power is lost along the length of the cable. This is called attenutation. Its unit is decibels per unit length. This loss depends on the length of the cable and also on frequency of signal. There are mainly 3 types of attentuation in coaxial cables.

  • Resistive loss -  This occurs due to resistance of the conductors. Current flowing through these conductors thus dissipate heat and thus power loss occurs.
  • Dielectric loss –  Coaxial cables require an internal structure of an insulating (dielectric) material to maintain the spacing between the center conductor and shield.The dielectric insulator also contributes to frequency dependent power loss occurs, as heat is dissipated.
  • Radiated loss – A small amount of power is radiated from the cable and this loss is the least important as it is small.
answered Jan 11, 2016 by Neethusha