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Usually a single coaxial cable is all you need to send over-the-air (OTA) signals from your outdoor TV antenna to your television. Or to connect your home with internet from the cable company.
But what if you want to hook up your antenna to a second TV in another room? Then you can split the coaxial cable running from your antenna into two cables, one feeding each television.
You split a coaxial cable by using a passive device called a coaxial cable splitter. A splitter is designed to attach several cables together in order to provide multiple outlets for one signal.
In this scenario, you’ll insert one end of the antenna coax into the splitter’s input port, then attach two more coax cables to the splitter’s output ports, and run each of these cables to a TV set.
If it sounds like a simple solution that’s because it is. The only (small) caveat is to ensure your TV signal – or whichever signal you’re trying to split, like internet or satellite TV – doesn’t get overly weakened, for instance by splitting it too often.
Why would you lose signal strength with a splitter? Each time you attach the coax to any device, be it a splitter, a set-top box, or a TV, you’re connecting the end of the cable (terminated in an F connector) with the port socket of the device. At the very least, the signal will slightly lose energy at the port due to insertion loss.
What is a Coaxial Cable Splitter?
In simple terms, a coaxial cable splitter (like the GE splitter with 2 output ports above) is a device that’s designed and built for the purpose of providing multiple outlets for one signal.
Your typical coaxial splitter has one input port for your coaxial cable and multiple output ports for joining other coaxial cables.
It’s a so-called passive device, meaning it doesn’t run on electricity and you don’t need to plug it in (unless it’s actually a distribution amplifier).
As a passive device, this means the signal power coming in will necessarily exceed the signal power going out (OK, save this thought for later).
Typically, coaxial splitters have 2, 3, 4, and 6 output ports (or even more) and the best of them maintain the proper impedance environment at both ends (input and output ports), which means they avoid multipath interference.
How to Use a Cable Splitter
To use a splitter, you simply attach the end of each coaxial cable (which must terminate with an F connector) into each port of the splitter.
Make sure each connection is tight and keep in mind that splitter connections aren’t generally weatherproof, so you may want to take measures if the splitter is installed outdoors.
Use the Appropriate Splitter
Keep in mind that cable splitters vary in both quality and frequency range. Quality might affect how much signal loss occurs on the splitter, and frequency range should be matched to the types of signals you’re splitting.
For instance, over-the-air TV signals in the US generally vary between 41 MHz and 608 MHz, so if you use a splitter rated for OTA TV for signals from your satellite dish, it may not work since satellite TV ranges up to 2000 MHz.
Conversely though, you may use a splitter rated for satellite TV for signals from your OTA TV antenna. But in any case check the frequency range printed on the splitter’s label.
Ensure as well that the impedance of the splitter matches what you’re connecting it to. For example, televisions and the like are 75-ohm devices, so your splitter should be rated for this impedance.
Does a Coaxial Cable Splitter Cause Signal Loss?
As mentioned above, you’ll get slight insertion loss whenever you plug the coax cable into any device.
Additionally with a splitter, you’re effectively dividing the incoming signal into however many outgoing cables are attached to it.
So if you’re using a two-way splitter (which has two output ports), the incoming signal will generally be divided in two and each half sent down each outgoing cable.
In terms of signal loss, this is in addition to the slight insertion loss the input signal has when it enters the splitter’s input port.
The more output ports a splitter has, the more cumulative signal loss that occurs. Admittedly this isn’t much loss generally, but the higher the number of ports you’re using, the more your signal can be affected.
The table below estimates signal loss occurring on a two-way and four-way splitter, in addition to insertion loss. Keep in mind this table is only an estimate and you may find slightly different estimates elsewhere.
Description | Signal loss (decibels) |
|---|---|
2-way splitter | ~ 3.5 dB per output port (~7 dB total loss) |
4-way splitter | ~ 7 dB per output port (~28 dB total loss) |
F-type connector on a television set for the coaxial cable | ~ 0.5 dB per connector |
How to Overcome Signal Loss From a Splitter
Chances are that if your cable run from the source is up to 100 feet in length, and you’re using a splitter with a small number of ports, your receiving device will get the signal just fine.
But if you purchase a splitter with more output ports than you need (e.g., you get a six-way splitter when you only need to connect two TVs or devices to your antenna), or if the splitter is of cheap quality, then you may be losing more signal than you need to.
You should get a splitter whose number of output ports matches the number of devices you need to connect to, and no more. Make sure to cap any unused splitter ports to prevent excess signal loss.
If you feel that signal loss either at the splitter or somewhere else along the line is so great that it’s affecting signal quality, consider replacing the splitter with a distribution amplifier with the appropriate number of output ports.
How to Install a Cable Splitter
Below are general steps for setting up a coaxial cable splitter for your home.
Step 1: Get the Right Cable Splitter
You’ll want a coaxial cable splitter that’s designed for what you want to do:
- The splitter’s frequency range should match that of the type of signal you intend to split (i.e., OTA TV, cable TV, satellite TV, etc.)
- The splitter’s impedance should match the impedance of connected devices. For instance, for OTA TV, this is 75 ohms
- The splitter’s output ports should roughly match the number of cables going out
When you obtain new coaxial cable, you may consider getting modern RG 6, which has more shielding and insulation from interference than RG 59.
Step 2: Find the Main Coaxial Cable
Once you’ve bought the appropriate splitter, you’ll need to locate the main coaxial cable – the one whose signal you’ll be splitting.
Sometimes this is as easy as finding where it leads from your antenna into the home. Other times you may need to trace it through your attic and behind walls.
You’ll probably need to shorten the cable at the place you intend to set up the splitter, by cutting it in two and placing an F connector at the end of it, in order to plug it into the splitter.
My guide on extending a coaxial cable has a section on how to do this.
Step 3: Connect All the Appropriate Cables
Attach both the input cable and the output cables into the splitter, which is straightforward to do using the cables’ threaded F connectors.
Plug the other ends of the output cables into your devices. Some devices may not possess coaxial inputs but instead only use HDMI and USB, which you may need to convert as appropriate.
Step 4: Turn on the TV or Device
Once you’ve connected all the devices to the splitter, turn on the TV or whichever device you’ve connected to check the signal.
If you’re using a TV antenna, make sure to run a channel scan and note the indicated signal strength of each channel, which may point to the need for an amplifier.
Final Thoughts
Splitting or dividing a coaxial cable to provide signal to multiple devices is a straightforward task that mainly involves attaching your existing cable to a splitter device, and running separate coax cables from the splitter to receiving devices like your TV.
The main concern is potential signal loss due to setting up a splitter between the source and the receiving devices, but in the majority of installations this is of little concern.
Although above I frequently mention TV antennas as a signal source, the source could be anything that uses a coaxial cable.
