How To Test Coax Cable Without Multimeter

Watching your best TV shows or browsing through your favorite internet platform at home are certain things we love and don’t tolerate interruptions with. 

However, that “no signal” or “no internet connection” error comes up, and we have to make fixes fast. The coax cable is a component that is directly responsible for the supply of your signal, but many people don’t know how to diagnose it for issues. 

This article presents you with all you need to know about testing the cable, especially if you don’t have a multimeter by your side and need accurate reliable results. Let’s get right in.

how to test coax cable without multimeter

What Is A Coax Cable?

A coaxial or coax cable is a copper cable used to transmit a satellite antenna, television and radio signal, and ethernet connectivity between a company and its end user. 

It is made up of a primary copper cable that is initially surrounded by one layer of insulation (dielectric layer), and this insulation is surrounded by a metal mesh or foil used as grounding attached to the coax cable connector. Another layer of insulation then coats the metal mesh. 

This bulky layer of components helps to prevent electricity from interfering with the signal in the coax cable, given the amount of data transferred through it.

There are different coaxial cables and connectors, but all these work and may be diagnosed the same way. When they develop faults, you experience bad signals on your cable TV, radio, or internet modem. 

coax cable

You may use a multimeter to diagnose a coaxial cable for faults by testing out its impedance. However, the multimeter test isn’t comprehensive enough to give you an idea of whether the cable possesses connectivity.

For example, a multimeter may indicate that the cable has the right impedance even when there is a signal leak due to loopholes in its insulation. This is where other testing methods come in.

Tools Required To Test Coax Cable Without Multimeter

Some of the tools you need to test a coaxial cable in your home include 

  • A compatible modem
  • A coax cable tester, particularly the DSS – 01

How To Test Coax Cable Without Multimeter

To test a coax cable without a multimeter, you use a coax cable tester to check for signals within the cable or insert it into a modem to test its connectivity. The coax cable tester is the easiest and fastest testing method for faults within a coax cable.

We will dive further into each of these steps.

  1. Get A DSS-01 Tester

Using a coaxial cable tester is the fastest and most reliable method of checking whether your coax cable carries connectivity. Out of the multiple options in the market, the DSS-01 provides you with the best and most accurate results.

Cable TV companies apply a particular signal frequency to transmit data to your home or office. The DSS – 01 device utilizes patented technology to identify this specific signal frequency and determines whether the cable is live with the right amount of connectivity. 

Unlike the multimeter, a coaxial cable tester gives you results that allow you to diagnose faults in the protective insulation accurately. You get this device from one of the stores close to you before taking the next steps.

  1. Insert Coax Cable Into The Cable Tester

Once you have the coax cable tester, you insert the coax cable into the port provided. You connect the coax cable the same way you connect it to the back of your modem or television, either by screwing or shoving it in.

Ensure the cable sits firmly in place and makes proper contact with the ports of the coax cable tester so it reads accurately. Poor connection between the cable and tester interferes with the diagnosis process, as the coax cable tester doesn’t receive full signal frequency.

If the connection seems shaky, adjust it till it is sturdy, then proceed to the next step.

  1. Turn On The Coax Cable Tester

For the next step, you turn on the coax cable tester and wait about 10 seconds for it to give a result, as simple as that.

  1. Evaluating Coax Cable Tester Results

Now, the coaxial cable tester you choose determines how you interpret results. The DSS-01 gives you a green light if the cable is okay and supplies the right signal frequency.

If you have a flashing red light, the cable is either bad or the signal within it is too poor to supply cable TV, internet, or radio connectivity effectively. 

Some coax cable testers additionally work with beeps. They usually illuminate a light to represent that there is continuity within the wire and then beep to show that there is a proper level of signal frequency within the cable. 

You replace the coax cable if you don’t get the right indication from the tester you use. If you still don’t get an appropriate result from your new coax cable, you may then check out your antenna outside the house if you have one or contact your TV or internet service supplier.

Using the DSS-01 coax cable tester helps you save time. If you don’t have one, however, you may also use your modem.

Testing A Coax Cable With A Modem

The modem test is only great if your coax cable supplies internet connectivity, as a wireless router is more portable than a TV. In this test, you move the router to all the cables you wish to test and see if you get an internet connection from the router.

Just like in the previous test, you connect the coax cable to the modem the same way you connect it to any other device, which is by screwing or shoving it into the appropriate port. 

Once your coax cable makes the right connection with the modem, you then connect to it to test out its internet connectivity. If you get internet access through the modem, then you know the coax cable is working properly. 

testing a coax cable with a modem

On the other hand, if you don’t receive internet connectivity, then the coax cable may be bad and needs to be changed.

One thing to note when testing multiple coax cables using the same modem. If all the coax cable tests present you with no internet connection, the problem may be with the modem itself and not the coax cables. Check it for faults.

If your coaxial cable works with cable TV, you simply plug it into our decoder and check whether you get a signal. Of course, you know you have a signal when your video starts playing smoothly.


Diagnosing your coaxial cable for faults at home doesn’t require you to take up multiple complicated steps and procedures. You simply utilize a dedicated coax cable tester or your decoder/modem to find faults.

The modem test takes some time to complete and is visibly more stressful than the test using a coax cable tester.

Frequently Asked Questions

How Do I Know If My Coax Cable Is Active?

You insert your cable into the DSS-01 coax cable tester and check whether you get a green light. A red light means the cable is not active. Some testers opt for beeps to show if the cable is active or not.

How Do I Find A Break In A Coaxial Cable?

A multimeter allows you to accurately find breaks in coax cables. You set the multimeter to measure capacitance or impedance and apply its probes to get a value from the cable.

Should There Be Voltage On Coax Cable?

A coaxial cable isn’t expected to hold any amount of voltage. If you get a voltage reading exceeding 50 AC volts from the cable, then there may be interference with its signal frequency.

Alex Klein Author


Alex Klein is an electrical engineer with more than 15 years of expertise. He is the host of the Electro University YouTube channel, which has thousands of subscribers.