75 Ohm vs. 50 Ohm - Coaxial Comparison

September 21, 2017 at 8:00 AM

 

Ohm may look like something you’d say while meditating, but when it comes to coaxial cables, it is actually a unit of resistance. Ohms measure the impedance within the cable. Impedance is resistance to the flow of electrical current through a circuit.

 

A smaller Ohm measurement equals less impedance. This means that a 50 Ohm cable has less resistance to the electrical current than a 75 Ohm cable. Though there really isn’t a "good" or "bad" level of impedance, it just depends on what is right for your application.

 

75 Ohm cables are the standard coaxial cables used throughout the home, they are often pre-wired into many homes and businesses. The primary application for 75 Ohm cables is transmitting video and audio signals. They are used to connect televisions to cable and satellite receivers and internet routers. These cables are ideal for smaller applications where a signal is transmitted up to 50 feet before the signal is repeated by an active device.

 

50 Ohm coaxial cables are mainly utilized in wired and wireless networks to relay data signals. Low-loss 50 Ohm cables are used for transferring RF signals in wireless networks. For commercial installations, 50 Ohm cables typically have the advantage over 75 Ohm because they perform better (less attenuation than 75 Ohm) over longer distances of more than 100 feet and over larger areas. The disadvantage of 50 Ohm cables is that they are much thicker and use larger connectors. Typical applications for 50 Ohm cables include GPS, cellular and test and measurement applications.

 

To recap, for the lowest impedance of electrical current, 50 Ohm is the best bet. 75 Ohm cables lose almost two times the amount of dB gain every 10 feet when compared to 50 Ohm cables.

 

Also, keep in mind that the 50 Ohm and 75 Ohm ratings only refer to the cables themselves and they can be mixed and matched with cables and connectors in any other system.

 

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