How to Build a Coaxial Cable Signal Strength Meter
Durable and reliable, coaxial cable has been the mainstay for providing homes with cable television since the mid-twentieth century. In today's world of digital television, coaxial cable now sees more use in connecting homes with high-speed cable Internet. These cables are made up of a wound copper core covered by a thick layer of insulation, terminating in a screw-on pin that connects to the female coaxial input on your device. When you have trouble with the cables, the best way to check them is with a signal meter, which is a simple device that you can build at home -- as long as you have some knowledge of electronics.
Warm your soldering iron by plugging it in and waiting a few minutes.
Lay out the circuit as depicted in the schematic in the References section. As you can see, the circuit requires three capacitors, two op-amps, two resistors, an integrated chip (74HC4040) and 16-gauge wire to connect all the components.
Solder all the components together as depicted in the schematic. It is easy to install the components on a bread-board to keep them from shitting and possibly shorting when you move the device.
Attach the completed tester to a BNC tee, which will allow you to connect the device to the other components.
Connect your oscilloscope to one arm of the BNC tee.
Attach the cable under test to the other arm of the BNC tee.
Look at the oscilloscope reading. If you see a square waveform, the cable is shorted. If you see a waveform with multiple steps to it, the cable is functioning properly. Refer to the schematic in the References section to see examples of these wave forms.