Components
An
RG-59 cable is made of four components. The outer plastic sheath
provides outer protection. Underneath that is a copper-braided
shield, to provide further protection. An inner dielectric insulator
insulates the cable. The final piece is the copper-plated core,
which lies underneath all of the other components.
Frequency
The
cable operates at a characteristic impedance of 75 ohms. The cable
is typically used for base band frequencies. Base band frequencies
are signals whose frequencies start at zero. Composite video, a
popular signal used in televisions, is a base band frequency. The
RG-59 can also transmit high frequencies, such as broadcast
frequencies, although not as well.
Distances
RG-59
cables are only effect at short distances. Over longer distances,
they have a high-frequency power loss that makes them makes them
less than an ideal choice for transmitting high frequencies. They
are effective at short distances, which is why they are commonly
used for connecting devices within 5 or 6 feet.
Common Devices
RG-59
cables are frequently packaged with devices such as VCRs and cable
boxes, due to the fact that they are more effective at short ranges.
Since these devices are usually within a couple of feet of the
television they are connected to, RG-59 cables are the ideal choice
to transmit the composite video signal.
Similar Cables
Where
RG-59 cables are ineffective at long ranges, RG-6 and RG-11 cable
take over. These cables are similar in design and function, but they
do not have the high frequency power loss that the RG-59 does and
are more useful for doing the same job at longer distances.
Fiber-optic cables are even more effective, and many cable companies
have begun the switch to implementing fiber optics into their cable
networks.
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