Completed coaxial TV cable join

How to Rejoin a Cut Coaxial TV Cable

Here’s what to do when you’ve accidentally cut an RG6 or RG59 coaxial TV cable in your roof or wall. This how to guide will show you how to join the cable so that your Digital TV will work again.

This procedure is mainly aimed at installed coaxial cables. If you accidentally cut or break a fly lead that goes from the wall to the back of your TV it’s best to replace it.

A Bad Joint
A Bad Joint – someone has simply twisted together the central conductor and shields. Why can’t you join a cable like this?

The end result is a cable that works nearly as well as if you hadn’t broken it in the first place. You will have some loss of signal from the connectors and joiner, but it’s much better than doing any other kind of joint without the proper connectors and joiner.

Parts and Tools

To do this, you’ll need to the following parts(links go to RG6 parts, but if using RG59 cable, change your search appropriately):

You’ll also need these tools:


  1. Try to pull some slack cable so you have at least 10 centimetres of overlap. If the cable is tight it can be hard to do the terminations(putting ends on the cable) and joint the cable.
  2. Cut the damaged ends off the cable with a pair of cutters. This will give you a clean cut end to work with.

    Cutting the damaged end of the cable off
    Cutting the damaged end of the cable off
  3. Strip the two cable ends with a rotary stripper. You can also strip the cable with a pair of cutters, but it’s harder.
  4. Terminate the cables with F connectors. You can use crimp or compression F connectors, but I recommend compression. Twist-on F connectors are also available, but I don’t recommend them.

    Terminated ends of the cable ready to be re-joined
    Terminated ends of the cable ready to be re-joined
  5. Screw both ends of the cable into either end of an F to F female adaptor(find them on eBay by searching F-type female joiner). They need to be firmly finger tight. It doesn’t matter which way around you put the two ends in.

    Completed coaxial TV cable join
    Completed coaxial TV cable join

Why fix bad joints? Why can’t you just twist the wires together?

Electrically, twisting the conductors together is fine. Twisted connections like this would barely introduce a few ohms resistance if that, particularly if done well. Electricity would flow along the cable without a real issue. The problem is radio frequency signals are not just electricity.

Electricity is delivered as either Direct Current(DC) or low frequency. The standard AC(alternating current) electrical feed in Australia is just 50hz. In the USA it’s 60hz. That means the voltage undulates from one peak to another 50 or 60 times per second. At that frequency or no frequency(DC) a good connection between any two pieces of metal will work just fine. Digital TV works on frequencies beginning at around 196000000hz. That’s 196000000 signal undulations per second.

The higher a frequency gets the more and more that signal begins to behave like light. Sharp bends in the medium carrying the signal can create a reflection, much like a mirror. The reflected signal can interfere with the incoming signal. Lots of other interesting effects also begin to occur.

Another big issue with the reception of Digital TV signals, particularly when the signal is weak, is noise. Noise is just a natural by-product of the big bang(which accounts of about 10% of the fuzzy signal you’ll see on an blank TV channel in analogue mode), stars, Jupiter, the Sun and all the other electronic devices that exist all around this planet. Noise of particularly close high power devices like microwaves, computers and mobile phones will be picked up by any metal object, like a cable.

Normally the shield mesh of a cable intercepts that noise and prevents it from getting to the central core of your TV cable which carries the signal. If you have an unshielded join in your cable, like the one shown above, the noise can directly enter the cable via the exposed central conductor.

If you have a weak signal in your area it probably will be overwhelmed by the noise and reflections caused by the bad joint. Even if it does work normally on any given day, it will be unreliable. All it may take is someone to use a mobile phone near by, or to start their microwave or to use a computer. That may be enough to knock out one or two channels for a period of time while the device is in use.

So in conclusion, if there’s any bad joints in your house’s TV cabling or your TV fly lead, I strongly suggest replacing that cable with good quality RG6 Quad Shield cable. If you can’t replace it with an unjoined cable, use the procedure above to properly join the cable.

Even if it works now on all channels, consider replacing it before you have a problem.