How to Split a Coaxial Cable (While Minimizing Signal Loss)

By Greg Martinez / October 19, 2022
how to use and install cable splitter

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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?

GE Digital 2-Way 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.

Alexis Lechuga - July 29, 2020

Hello Greg, Will a digital coaxial cable work as a replacement for a broken left surround sound speaker cable from a Vizio soundbar and subwoofer system? just wanted to make sure before I purchase one, Thanks!

joe - August 2, 2020

If I buy the 4way or 6way splitter, do I have to use all 4/6 out ports? thanks

Greg Martinez - August 3, 2020

Not at all—you don’t need to use all the ports, but don’t forget that all ports on the splitter will cause some signal leakage (but most likely not enough to affect your signal). So I’d try to get a splitter whose number of output ports matches exactly the number of TVs/devices you need to distribute signal to. If you already have a splitter and not all ports are being used, you can also separately purchase caps to put on the unused ports.

Saide Jerson - August 8, 2020

I would really like to hook up my TV to a receiver to play sound through. Can I just use this cable or do I need a digital to analog converter? thanks

Greg Martinez - August 9, 2020

If you mean a soundbar then your TV will need to support HDMI out (most don’t), so check with the manufacturer’s instructions. Otherwise look into getting a digital optical cable.

Phil - August 12, 2020

Is it possible to connect two or three antennas to one tv with this splitter? vice versa, can I connect 3 or two tvs to one antenna? Thanks!

Greg Martinez - August 13, 2020

Yes you could combine several antennas but I’m not sure a splitter would be the best device for this – you might want to use signal combiners (see my article on “Stacking TV Antennas” for details). Yes vice versa you can connect n TVs with one antenna using a splitter with n output ports.

A. ABONAR - September 3, 2020

Can i use a coaxial splitter for a car radio signal? or even wifi signal?

Greg Martinez - September 4, 2020

Car radio: not sure what you’re trying to do. Your WiFi router may have a coaxial F-connector and if so then yes you can divide the signal among other devices depending on the application.

Mindy Fisher - September 9, 2020

I have a lot of different cables here in our house, my question is, how can I identify a digital coax just by their appearance. Or what test should I do to determine the signals? I’m not good at tools so I don’t have any idea how to separate the best one (digital coax) to an ordinary coaxial cable.

Greg Martinez - September 10, 2020

Hi Mindy, it’s true this article doesn’t have pictures of coax cable. Check out my other article “The Best Coaxial Cable on the Market Today” for examples. Professionals generally use a multimeter to test TV signal strength on such a cable.

Greg Martinez - September 14, 2020

Hi Alexis, honestly not sure about that but check if it has an F-connector for coaxial cable on the back.

Bill - October 1, 2023

Should splitter be closer to antenna or tv’s or does it matter

Greg Martinez - October 1, 2023

Generally speaking it’s better to place it closer to the TV antenna, if you can.

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