It can be quite confusing trying to work out the difference between a Tap, a Combiner, a Diplexer, and a Splitter because they all look very much the same. And just to make it more confusing, some splitters and diplexers are also combiners, and parts can be passive or active, powered, or unpowered.
Let us go through each part such as a splitter, tap, coupler to determine what it is used for.
A tap, which is a very general-purpose term, could be described as a special-purpose splitter. All the signals are equal in a normal splitter; however, the signals are not equal in a tap.
DIYers would rarely use taps in their installation.
In commercial installations, a tap is used to allow the trunk line, or main line, to have an exceptionally high signal strength, thus allowing for a long run without using an amplifier.
In traditional cable systems, when a house is being wired for Cable TV, a tap is used to transition from the master cable running through the neighborhood. While master lines are purposed for long runs from the cable head-end, a tap adjusts the line to make it more suitable for in-home use. A tap can completely alter the signal or the voltage.
The term "tap" is used by some people to describe a device that alters the signal from one type to another; however, this is not actually correct. For their home use, Verizon uses a device known as an ONT (Optical Network Terminal) to change to coaxial cable from fiber optic cable, and while installers refer to this as a tap, that is not the whole story.
The definition of a combiner could be the device used to combine different input signals with different frequencies into one single output to feed one antenna. Or - when two signals are put onto a single cable without any "translation", the device used is known as a combiner. Basically, a combiner takes all the signals and mixes them together, which works well when signals are meant to be combined.
Diplexers can easily be confused with combiners, and they basically do the same job. However, while a diplexer is just a fancy combiner, there's a lot more to it because it delivers more precision. A diplexer cleanly and carefully allows two separate sets of signals to survive on the same cable.
When two signals are taken from two different cables and logically put on the same cable, the device used is known as a diplexer. If you wanted to add an antenna signal to an existing cable, you would use a diplexer. Note that there are various types of diplexers.
A passive diplexer is more-or-less just a combiner. It takes two compatible signals and puts them on the same cable.
An active diplexer adds power to the line, ensuring limited loss when signals move through the system. A diplexer is also capable of shifting frequencies to make sure they work together. This type of diplexer is also known as a modulator.
More About Diplexers.
Cables can be complex, which is why you need diplexers. All you see when you look at a cable is a long line made of wire, but that wire can potentially carry several different frequencies, which explains why you can get many channels – they simply exist in different locations on the wire.
The FCC ensures there's no interference with broadcast signals, and satellite and cable companies ensure their channels are not on the same frequencies as each other.
Generally, satellite and cable signals are not on the same frequency as over-the-air antennas, so using diplexers is not a problem. DIRECTV, on the other hand, has its whole-home, on-demand information, and antenna signal in the same place, thus explaining why an antenna and whole-home can't be used on the same cable.
Diplexers are not typically found in in-home installations; however, apartment and commercial setups use diplexers to allow the same cable to be used for both internet and satellite TV.
You’ have probably noticed that diplexers and splitters look almost the same – both have one connection on one end and multiple connections on the other. The difference is that a splitter takes in one signal and makes two out, while a diplexer or combiner takes in two signals and makes one out.
Splitters are commonly used for adding a second television to an existing cable. If you already have an antenna, a splitter can be used to make that antenna service several television sets. With a satellite or cable system, a splitter could be used to add TV to a separate room. This is how most of today's modern systems use splitters, however with older systems a separate line would need to be run from a central switch to each TV. You need to know up-front if yours is a splitable system.
While splitting might sound like the ideal way to add additional outlets, keep in mind that every time a signal is split, its strength is halved. You're sending half as much signal through each line when you split out the signal. You may feel that you have good quality signal now, but it won't get the job done if you split it too many times. You should carefully consider if you have a strong enough signal before you decide to split the signal. In areas where the signal is exceptionally low it is often advised that two antennas be used instead of a splitter. Whether two devices are connected to the splitter or not, the signal will always be divided. Learn how splitters versus taps differ.
Explaining Multipurpose Devices.
Don't be taken in by inexpensive devices that are advertised as a combination splitter/diplexer. They probably won't be very effective at either.
We strongly suggest you find a product such as splitter, tap, filter that serves your precise purpose. As the cell booster parts & accessories become more expensive, a single device will more likely have the required electronics to serve both purposes. When it comes to multi-switches, modulators, and other specialized devices, splitting and diplexing are just part of the key functions they need to operate.
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