Which is Better: 50 Ohm or 75 Ohm Cables & Signal Amplifiers?
Mar 19, 2018
100 feet 50 ohm cable
100 feet 75 ohm cable
Understanding the Difference between 50-Ohm and 75-Ohm Coaxial Cables, And Knowing Which One to Choose.
Wilson Electronics, weBoost, SureCall, etc. typically use either a 50-Ohm Wilson400, SureCall400, or equivalent LMR-400 coaxial cable with N-connectors or a 75-Ohm RG-6 coaxial cable with F-connectors for installing their home and commercial cell phone signal boosters. "Ohm" refers to unit of cable impedance measurement.
In this post we will explain the major differences according to certified installers between these two coaxial cable types.
What Is "Impedance"?
Impedance is how cables are measured. It refers to the amount of resistance compared to the flow of electrical energy. A 50-Ohm cable will provide a better result than a 75-Ohm cable. This means that you will achieve better performance from your installs with a lesser Ohm "number".
About 75-Ohm Coaxial Cable.
Why would an installer install 75-Ohm if one can achieve a better result with a 50-Ohm cable? The answer is simple. We already have 75-Ohm coaxial cables right throughout many of our buildings. They are often pre-wired into businesses and homes. You will find them at the back of your television set. You will find them in the back of your Internet router as well as satellite and cable TV boxes. 75-Ohm coaxial cable is primarily used for audio and video. This is the reason why it is used so widely throughout our homes and business premises. Therefore, it saves on cable costs and their labor-intensive re-installation process which is explained below in "About 50-Ohm Coaxial Cable" section.
For smaller dwelling applications 75-Ohm has become the norm in America because it more than adequately transmits signal up to 50 feet of cable. Home installation with 75-Ohm is maximized at 5,000 square ft.
About 50-Ohm Coaxial Cable.
50-Ohm coaxial cable is the perfect choice for commercial installations when the building coverage ranges between 7,500 and 100,000 square ft. and the cable runs for 100+ feet. 50-Ohm coaxial cable is typically used for data, which is why it is the preferred cable for cell phone boosters.
The trade-off with 50-Ohm cabling is larger connectors and thicker cable housing. The 50 Ohm cabling is quite noticeably bigger than 75-Ohm cabling. Another thing to note: 50-Ohm cabling is not as common as 75-Ohm cabling. Therefore, if your building has not been prewired for this type of cabling - it can be much more difficult to run the cable.
Our Suggestion.
We suggest 75-Ohm coaxial cabling for any building with a coverage under 7,500 square ft. if 75 Ohm cables are pre-installed. However, if you’re looking for the very best, then we suggest you go with 50-Ohm coaxial cable.
Which Impedance Signal Booster System is Best: 50 Ohm or 75 Ohm?
Based on information above, and the choice made for the cables, the respective Ohm cell phone signal booster system can be installed. The same goes with signal booster antennas because they have built-in connectors that accomodate respective type cable connectors. Keep in mind that the terms 50-Ohm and 75-Ohm only refer to the cables themselves – they do not refer to cell phone signal boosting systems. Yes, you can use different cables and connectors with any system. However, doing this can lead to increased decibel loss. Remember that the longer the cable, the farther the data must travel, potentially resulting in additional loss.
For every 10 feet, 75-Ohm loses approximately twice the amount of dB gain when compared to 50-Ohm. Therefore, at 50 feet of cable - you have potentially lost -2 dB gain. This means that, when referring to maintaining signal derived from the same source, 50-Ohm is approximately 1.6 times more powerful than 75-Ohm.
If you would like to learn more about boosting your cellular signal and help with cell phone signal booster installation, why not check out our guide on cell phone signal boosters?
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7 comments
50 Ohm cables sound better, but I’ll leave the installation specifics to a professional installer. I don’t understand all the details and I wouldn’t want to have a good signal amplifier do less than a perfect job because I put the wrong cable in. I’ll leave it to the professionals.
50 Ohm cables are usually used in two way radio equipment and broadcast equipment (tv and radio, where delivery of signal power is the objective). 75 Ohm cables are used in video equipment (transmission of the signal not power). The DC resistance of 100 ft 50 Ohm and 75 Ohm cables are about the same (a few Ohms) as measured with a multimeter. The impedance is determined by the distance between the outer diameter of the inner conductor and the inner diameter of the outer shielding conductor and the dielectric property of the insulating material between them.
The comment left by Marianne Oelund on Apr 29, 2020 is correct.
The article is not accurately addressing coax cable attributes. Impedance, particularly at high frequencies, is not directly related to cable resistance; they are different attributes, and are often confusing to users.
While coax impedance for recieving signals is more forgiving, coax applications for transmission can be critical. Matching transmitter final-stage output to transmission line plus antenna loading and tuning are important and must be optimized.
For recieving, it doesn’t matter too much.
For transmitting, it can be very important.
If a device is transmitting HF, VHF, UHF, and specifies 50 ohm, then use 50 ohm cable and 50 ohm connectors.
This is a technically poor and misleading article. Choice of cable is driven by the termination impedance of the equipment that it interconnects. If your equipment is designed for 75 ohm cable, that is what you must use. If your equipment is designed for 50 ohm cable, then it is necessary to use that impedance. Mixing cable impedance with equipment designed for a different impedance causes signal reflections that produce ghosting in analog systems, or bit errors in digital systems.
Regarding transmission distance, there are several choices for a given impedance. For example at 75 ohms, you can use RG59, RG6 or RG11. For shorter runs, RG59 is fine, but for longer runs, RG11 may be required.
I’ve never given much thought to the support equipment for cell phone boosters but things like coaxial cable for cell phone boosters makes sense. Coaxial cable is used for many electronics so I guess you should know the difference between 50 Ohm coaxial cable and 75 Ohm coaxial cable, especially for something sensitive like your cell phone signal. I’m going to have to read this a couple times to get a good feel for it.
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I wasn’t sure where to start but this website seems to have a lot of tech stuff. What are the best car gadgets in 2018? Is there anything here you can direct me to?