Start by inspecting both ends of the coaxial cable for any loose or improperly connected plugs or adapters. Coaxial cable connections, whether threaded or push-and-twist, should be tightly secured. Loose connections are a leading cause of intermittent or no signal. Ensure that the coaxial connectors are fully seated in the input/output ports of both the CCTV camera and the DVR or monitor. If connectors are not aligned or are loosely attached, reattach them securely. Inspect the connectors for corrosion, which can affect the integrity of the signal.

Visually inspect the entire length of the coaxial cable for any obvious signs of wear, damage, or physical stress, such as cuts, abrasions, crushing, or punctures. Coaxial cables are designed with layers of protection, including an insulating layer and a shield to prevent signal interference, but damage to the cable can compromise its performance. Even minor cuts can result in significant signal degradation or total loss of video feed. If any damage is identified, replace the affected section or the entire cable, depending on the extent of the damage.

Coaxial cables are particularly susceptible to signal loss when bent at sharp angles. Over time, excessive bending can damage the internal wire and cause signal attenuation, resulting in a degraded video feed. Inspect the cable for any tight bends, kinks, or areas where the cable might be pinched or folded. These issues can break the copper core or disrupt the shielding, leading to poor signal transmission. Gently straighten any minor bends, and if the cable has been damaged severely, replace it. Proper cable management practices can prevent this type of damage.

Using a CCTV tester or a digital multimeter with video signal testing capabilities, you can verify the strength and integrity of the video signal passing through the coaxial cable. If the cable is intact but the video feed is still poor, there may be signal degradation or attenuation. Test the signal at both the camera and the DVR (or monitor) end. If the signal is weak or shows a lot of noise, the cable might need to be replaced, or you may need to shorten the cable run if it exceeds recommended lengths. Ensure that the signal strength is within the acceptable range for optimal performance.

If you're using a power-over-coaxial (PoC) cable system, where both video and power are transmitted via the same cable, ensure that the power supply is functioning properly. A malfunctioning power supply can result in the camera failing to operate, or in reduced video quality or a complete lack of video output. Test the power at the camera's end to ensure that the correct voltage is being supplied. If you notice any inconsistencies or if the camera doesn’t power up at all, the issue could be with the power supply unit or the coaxial cable's power-conducting capabilities.

Longer cable runs can introduce signal attenuation, which results in lower video quality, particularly for high-definition video signals. Every coaxial cable has a limit to how far it can carry a signal without noticeable degradation. Typically, RG59 cables can transmit video reliably up to 300 feet, while RG6 cables can handle up to 500 feet. If your cable exceeds these lengths, consider using a signal amplifier or booster to restore the signal. If there is a noticeable drop in video quality or resolution at longer distances, reducing the cable length or adding a booster could solve the issue.