How does coaxial cable transmit power?

There isn't or shouldn't be any power in coaxial cable. It is just for the TV or computer hook up. Just so you can receive the signal from the broadcaster or Internet.

In several ways the previous answer is wrong.

Firstly coaxial cable is exactly like normal 2 wire cable (fig8 cable) except that instead of two separate wires running side by side separated by insulation) one wire is inside the other (again separated by insulation). There are many different types of coax (probably hundreds eg one i use is rg-58 which is for two way radios, another is rg-6 which is used for tv coax)

secondly- if any signal is to be passed through a cable- there has to be power flowing through it- it may be incredibly small (microvolts like from your tv antenna) or very large (hundreds of volts like in a high powered radio transmitter)

Even in a tv coax, if you have a `masthead amplifier' that only has 1 cable running up to the antenna and a funny box behind the tv that has 2 coax leads running into it and a plug-pack from a PowerPoint going into it as well- you would find that you are actually passing power up the coax from the PowerPoint plug-pack to the electronics up on top of the tv mast - power going up and tv signal coming down the same coax at the same time- saves on another two wires having to be run!!!

Many `cable' tv or internet cables have a similar `power over coax' arrangement for powering amplifiers on long cable runs, this is normally stopped by a filter before the end users outlet however (if the filter is faulty this can be the `tingle or zap' that you sometimes get when touching the outer screw connector of the coax plug)