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A bad cable splitter can cause a variety of symptoms, including:
  • Unusual noise from the wire, such as a faint buzzing sound
  • Complete loss of signal, which can lead to no picture or sound
  • Excessive attenuation of the signal, which can cause signal loss
  • Multiple reflections, which can cause ghosting (shadows on the picture)
  • Mismatch in impedance, which can result in reflections, poor communication on that signal line, and loss of signal
A splitter is a device that splits a cable signal between two or more devices. All cable splitters have some sort of signal loss.
Some common problems with coax splitters include:
  • Too much splitting
  • Connecting cable TV to cable internet modem
  • Improper cable/splitter choice
To address the loss of signal strength, you can try using an active splitter, which includes amplification.

Can a bad splitter cause internet issues?

A cable splitter can cause internet issues by weakening the signal level. This can cause intermittent loss of service or, in rare cases, service failure. Cable internet requires a strong signal to function correctly. Because the signal is being split, there may not be enough power to sustain a good connection.
A cable splitter is designed to split the signal without compromising the signal’s quality. However, the signal does get equally distributed among all output ports on the splitter.
If you have a very weak signal to begin with, you may see some issues. If you choose to use a splitter, make sure it’s rated at 3.5 dBmV.
If you need to connect your cable TV and internet only, you should use a 2-way splitter for optimal output.

How do you know if your cable splitter is bad?

Some signs that your cable splitter may be bad include:
  • Poor picture quality, such as pixelated images or lines across the screen
  • Substandard sound quality
  • Unexpected reflections on the COAX Trace
  • Ghosting, or multiple reflections or shadows on a picture
To test if your splitter is bad, you can try disconnecting the coaxial cables connected to the splitter and replacing them with new cables. If you still have a problem with your video, it may be the splitter that’s bad.
Splitters can go bad due to: Entropy, Corrosion, Manufacturing defects, Critters, Jiggling and vibration.
You can also test a splitter for through loss by:
  1. Measuring and recording the level of the signal source
  2. Terminating all but one of the output terminals of the splitter with a 75 ohm resistor
  3. Measuring the signal level at the unterminated output port with the Frequency Selective Voltmeter

How do you test a splitter?

To test a cable splitter for through loss, you can:
  1. Measure and record the level of the signal source.
  2. Terminate all but one of the output terminals of the splitter with a 75 ohm resistor.
  3. Measure the signal level at the unterminated output port with a Frequency Selective Voltmeter.
You can also test a cable splitter by simple substitution. Some splitters will show an open or a short between input and output terminals. Others will show an open or a short between signal terminal and the case.
You can also test a cable splitter by viewing the COAX Trace. If there is a good quality splitter in the circuit, there should be one and only one positive reflection corresponding to each un-terminated branch on the coax circuit.

How do you test a cable signal?

You can test a cable signal using a multimeter or a cable tester. A multimeter can verify the cable’s continuity and signal strength. A cable tester can notify you with a beep or green light if the cable is working properly.
You can also test a cable signal by plugging in a cable modem and checking its connection. If the modem connects like normal, that means a signal was detected.
Here are some other ways to test a cable signal:
  • Restart and reconnect your internet modem.
  • Check that the TV point in your room isn’t loose or wobbly.
  • Check that the splitter box is working fine.