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What’s the Difference Between 50 Ohm and 75 Ohm Coaxial Cable?

First, let’s look at 50 Ohm Coaxial Cables. Experimentation in the early 20th century determined that the best POWER HANDLING capability could be achieved by using 30 Ohm Coaxial Cable, whereas the lowest signal ATTENUATION (LOSS) could be achieved by using 77 Ohm Coaxial Cable. However, there are few dielectric materials suitable for use in a coaxial cable to support 30 Ohm impedance. Thus, 50 Ohm Coaxial Cable was selected as the ideal compromise; offering high power handling AND low attenuation characteristics.   With 50 Ohm Coaxial Cables being the best compromise solution, practically any application that demands high power handling capacity, i.e. 100 watts or more, will use 50 Ohm Coaxial Cable. A good rule of thumb is that any device that functions as a transmitter or transceiver tends to use 50 Ohm Coaxial Cable. This includes devices such as CB/Ham Radios, Broadcast Radio/TV Transmitters, Wi-Fi and Cellular Phone Repeaters and 2-Way Radios.   RG-58 Coaxial Cable is perhaps our most popular “gold standard” 50 Ohm Coaxial Cable product, because it provides acceptable performance for most applications at a very low price. Our next most popular is RG-174 Coaxial Cable. RG174 is great because it is so thin, i.e. 1/8th of an inch, allowing it to be used in real tight spaces such as feeding a GPS navigation antenna into a vehicle. For customers that want the absolute highest power handling capacity (1000 watts or greater), RG-213 Coaxial Cable is the way to go. RG213 is our thickest coaxial cable at nearly half an inch. However, not every case warrants high power handling, so 50 Ohm Coaxial Cable is not appropriate for every application. When the objective is to ensure that the signal gets through the cable in the most efficient way possible, losing very little signal strength in the process, 75 Ohm Coaxial Cable is the way to go. A good rule of thumb is that if the device being connected via coaxial cable is a receiver of some kind, 75 Ohm Coax is ideal. This includes devices such as Satellite and Cable TV Receiver Boxes, High Definition Televisions, AM/FM Radio Receivers and Police Scanners.   Another interesting application for 75 Ohm Coaxial Cable isCoaxial Digital Audio. This is the orange or black colored RCA jack commonly seen on HDTV’s, BluRay Disc Players and other Home Theater Gear. It is sometimes labeled as S/PDIF Out. It transfers the 5.1 Channel Dolby Digital Surround Sound signal to the home theater system for decoding and playback into the various speakers. Digital signals generally look like a square wave instead of the typical sine wave seen with analog signals like AC power or analog radio/TV.   The so-called “enemy” of a square wave digital signal is capacitance (remember this one?). This is because increased capacitance tends to “store” the peaks of the square waves, skewing the shape of the square to look more like a straight line. When this happens, the receiver has trouble reconstructing the signal after it has traveled down the coax. Technically 93 Ohm Coaxial Cable has the lowest capacitance of any type, but 93 Ohm Coax is rare and expensive. Thus, 75 Ohm Coax is the closest fit, offering not only low signal attenuation (loss), but also relatively low capacitance.   This combination of low attenuation and capacitance effectively make 75 Ohm Coaxial Cable the cable of choice for practically all types of digital audio, digital video and data signals. This is why every cable TV company uses 75 Ohm coax for distributing its digital video channels as well as its broadband internet data signals. Direct broadcast satellite dishes and over-the-air HDTV antennas also require 75 Ohm Coaxial Cable to ensure that all of the digital channels transfer down the cable with the lowest loss and distortion possible.   We do offer the typical RG-6 Coaxial Cable with Type F Connectors used for cable and satellite TV applications, and RG59 Coaxial Cables with BNC Connectors for other analog and digital video applications. We sell a lot of these cables to radio and television broadcasters and production companies to interlink their equipment. Older analog TV cameras and monitors in the studio will use RG-59 Coaxial Cables and newer digital TV cameras and monitors will use RG-59 as well for a high-quality digital video signal type known as the Serial Digital Interface (SDI). Finally, one last crucial point in regards to coaxial cables. The Impedance of the various devices being connected as well as the Coaxial Cable itself must match. So if you are, for instance, connecting a 75 Ohm video camera connection to a studio monitor, the coaxial cable must also be 75 Ohm AND the connectors on the coaxial cable (i.e. BNC connectors) must be 75 Ohm in Impedance. Every single time you have a mismatch in impedance, say between a 50 Ohm Coaxial Cable and a 75 Ohm Coaxial Connector (i.e. BNC), a standing wave develops.   A standing wave is a signal reflection that is essentially wasted. Every time a 50 and 75 Ohm Impedance mismatch occurs, about 5% of the signal is lost. These losses add up and can eventually degrade the signal to the point that it is unrecoverable or distorted. Some coaxial cable manufacturers will cut corners in this regard. The BNC connector, pictured above, was invented by our parent company, Amphenol, before World War 2. It is extremely popular, but most people don’t realize that they come in two versions: 50 Ohm and 75 Ohm. All of our coaxial cables at Cables on Demand always have the proper impedance matched connectors to line up with the coaxial cable being used.   One can view our entire selection of Coaxial Cable products at Cables on Demand by visiting our website ( I hope this blog post helped clarify any questions you may have regarding coaxial cable impedance and types. If you have any further questions, please don’t hesitate to contact us at:, Mob.: +86 13616872763



Whats is the Best Coax Cable for CCTV Camera Installations?

Whats is the Best Coax Cable for CCTV Camera Installations? Not all coaxial cable should be used for CCTV camera installations. RG59 coax cable is the industry standard and best choice for CCTV systems and HD over coax systems, however, not all RG59 is created equal. Be sure to read the spec before you buy.   This is what you need to know. Be sure to select RG59 cable with a solid copper core or CCS/ inner conductor and 95% copper or CCA braiding. Look at the specification in the website pages. These two elements are highlighted and the arrows point to the parts of the cable they refer to.   The impedance of CCTV cameras is 75 ohms. In order to have minimum video loss, you should use coax cable that also has an impedance of 75 ohms. Coax cable is also available in 50 ohm and 93 ohm. Do not use these for CCTV installation. Use ONLY 75 ohm cable.   Similar to RG-6, the RG-59 refers to ‘Radio Guide’ while 59 refers to the diameter size, i.e., .059 and uses a copper plate. This type of cable is recommended for a lower bandwidth, therefore, it’s ideal for CCTV installations particularly suitable for flats, apartments, societies, hotels and other interior, relatively smaller places. Hangzhou Aite RG59 coaxial cable is a foaming-based dielectric system. With a super gas injected from the foam insulation, the cable thus helps in providing a better quality signal which eventually helps for better surveillance.   RG6 can also be used for CCTV. It is also available with a solid copper core or CCS/ inner conductor and 95% AL-M or CCA braiding. RG6 can be run farther distances than RG59 without video loss, however, RG6 is a thicker, more rigid cable which is not as convenient to work with (especially around corners). RG59 is rated at 700 feet and RG6 is rated at 1000 feet for analog CCTV. RG59 is more typically used. Can I use CATV Coax Cable for CCTV? Like CCTV, cable television (CATV) is also typically wired using RG59 or RG6 coax cable, however it is not the same type of RG59 or RG6 that is used for CCTV installations. The difference is that the center conductor / inner conductor of CATV grade cable is made of steel or copper plated steel instead of copper. Steel has a much higher resistance than pure copper which leads to video loss at low frequency. Steel costs less than copper, which makes CATV cable cheaper than CCTV. CATV systems are able to use cable with a steel center because cable TV video uses much higher video frequencies than CCTV. The copper plating of clad cable is thick enough so that none of the radio frequency energy penetrates into the steel core to induce loss. CCTV video uses much lower frequencies which are lost or dropped when using steel or steel clad cable. To identify RG59 or RG6 for CATV, check the product specification and be on the lookup for terms such as “copper clad steel”, “aluminum foil inner shield”, “aluminum braid shield”. These are all characteristics coax cable that is used for CATV cable and should not be used for CCTV.   What is the Max Distance for CCTV Cable? What is the max distance that installers can run CCTV cable for video and power? Here is a question that I received from a customer recently. Hi Thomas, can you please assist. Is it possible to run power cable together with the video on RG59 Cable for a distance of 250 meters. I am a new CCTV technician who has just faced a challenge on an old installation which is not working properly. Here is the information that I provided. Analog CCTV camera video transmission is limited to 213 meters or 700 feet using RG59 coaxial cable, unless you use a video amplifier like this one Using this amp, you can run CCTV video up to 1000 meters / 3000 feet with RG59. The max distance that you can run power cable to the camera without voltage drop depends on the voltage, amount of power the camera draws in amps, and the gauge of the cable that you are using. You can use this voltage drop calculator and voltage drop chart. Can I use rg58 for video? A: RG-58 is 50-ohm coaxial cable and is typically used for radio communications and thin Ethernet networks. RG-59 is 75-ohm coaxial cable for CCTV and cable TV. Some also use RG-6 for video connections. The difference between RG-58 and RG-59; Covering up wood splints, scratches Q: What is the difference between RG-58 and RG-59 coaxial cable? A: RG-58 is 50-ohm coaxial cable and is typically used for radio communications and thin Ethernet networks. RG-59 is 75-ohm coaxial cable for CCTV and cable TV. Some also use RG-6 for video connections. The RG stands for Radio Guide. Remember that a coax cable is a radio frequency waveguide and the outer radius should not be distorted.   Q:Every once in a while I have a technician who will splinter or scratch a piece of wood or molding when drilling or installing contacts. It can get pretty expensive having a professional carpenter repair these mistakes. Do you have any suggestions on saving some money here? A: First, make sure your techs are using sharp bits for clean cutting holes. This will reduce the number of splinters. Second, make yourself some wood and furniture repair kits.   This saved me one time when a tech came out of a wall in the wrong place and started to drill a wood dresser. I used to call them “bo bo” kits. This can simply be a box of kids’ wax crayons. There are also professional restoration crayon kits. A little more money, but a better quality of crayons. Make sure to have plenty of earth and wood tone colors. Check with your local distributor for these kits. If you have any tips to share or have questions about installations or troubleshooting,