Can you explain what that means?
This question about 0.14db loss in coax Firstborn....
The loss in RF coaxial cable is quoted in dB of signal per length usually 100 meters or 100ft (30m).
The higher the figure of loss the lower the amount of signal will pass from one end to the other.
In WiFi systems the power at the antenna socket is approx 60-100milliwatts of RF power, now every 3dB of loss that the coax has, you lose half the power in the effect the cable has on the signal. This is all to do with the way the RF travels through the cable.
Better cables use a high spec foam that doesn't have has large a detrimental effect on the RF signal. Also the centre conductor plays a large part too it has to as it is this that carries the RF energy. The conductor like all things has a resistance that is measured in OHM's this is not to be confused with the impedance of the cable, all cables used in WiFi are 50 Ohms impedance. So with resistance comes heat because you cannot have voltage and current flowing through a conductor which has resistance without generating heat physics 101!!
The other part is the way the centre conductor actually passed the RF energy along its length. Because any round conductor has what is called Inductance with RF energy you have something called Skin Effect. This is because as the frequency increases that the RF energy is at then the more this causes the RF energy to only be conducted on the very outer skin on the wire and we are talking micro millimetres here hence the name Skin Effect, it is also known as current density in electrical distribution systems
The effect the screening has also helps to reduce loss in coax because if the screen is poor then the RF energy leeks out of the cable into the surrounding materials. Be it other cables or just the air, this is how leaky feeders work!!! So the better the screening the better the performance of the cable hence why the better cables have either a Aluminium foil or copper foil with a second layer of braided wire over this hence the name double screened coax.
Also the diameter of the outer conductor reduces loss in the current density because the current carried on the outer is spread over a much larger area of conductor compared to the relatively small diameter of the centre conductor.
The reasons all this happens is the fact that the RF Energy is an EM field, or Electro Magnetic Field. This is also the reason why when making Earth connections for Lightning conductors they use a flat copper strap rather than wire because Lightning has the same characteristics as RF energy!!!
In a flat wide conductor the current density is dissipated across a much larger area than that of a round conductor. But you can not use a flat conductor in coax other wise the RF impedance would not be constant due to the difference in the thickness of the conductor at the edge compared to the width. This is why coax is round and not flat.
So coax is just not something that you take with a pinch of salt because it makes ALL the difference and the higher in frequency you go the more and more important the quality and characteristics of the coax becomes.
Hope this explains it in enough detail but without causing too much of a headache
