Coax Cable for CCTV Distance: The Limit Is Equalisation, Not Cable
Quick answer / TL;DR: Short answer: analogue video over RG59 is typically practical to a few hundred metres and RG6 goes further, but the real limit is whether the recorder can equalise the high-frequency loss. Beyond coax's practical range, use a video balun over twisted pair or move to IP. A ground loop between buildings mimics distance loss and must be ruled out first.
The 100-metre wall is a standard, not a suggestion: three legitimate ways past it.Analogue CCTV over coax has a distance limit that is often quoted as a single number and is really a range, because the limit depends on the cable, the camera and the recorder's ability to compensate.
The compensation matters as much as the loss. A recorder that can equalise a long run extends the practical distance considerably, and one that cannot stops much earlier.
This article covers the ranges, the alternatives beyond them, and the fault that looks like distance but is not.
An analogue video signal carries most of its detail at the higher frequencies, and coax attenuates those more than the low frequencies. The result is a picture that softens before it fails.
Equalisation applies the inverse curve at the recorder. Its range setting is what actually determines whether a long run produces a usable image.
Practical Ranges
| Cable | Typical practical range | Notes |
|---|
| RG59 | Shorter runs | Thinner, higher loss per metre |
| RG6 | Considerably further than RG59 | Better choice for any long run |
| RG11 | Longest coax option | Stiffer, harder to route |
| Twisted pair with baluns | Often further than coax | Cheaper cable, needs a pair |
| Fiber | Beyond all copper options | Requires power at the camera |
The ranges in the table are indicative. The recorder's equaliser, the camera's output level and the number of connectors all move the figure.
The Fault That Looks Like Distance
- A ground potential difference between buildings appears as hum bars or a rolling image, not as loss
- A damaged connector appears as a sharp degradation at one point in the run
- A cable that was kinked shows reflection, which softens the image like loss does
- Water in an outdoor connector degrades gradually and worsens with weather
- Test with a known-good camera and a known-good monitor before condemning the cable
Real-World Applications
A perimeter camera at two hundred metres on RG59 shows a soft image. Replacing the last section with RG6 and setting the recorder's equaliser correctly restores it.
A camera on an outbuilding shows hum bars. The cause is a ground potential difference, and a balun pair or fiber resolves it where cable changes do not.
A car park installation uses twisted pair with baluns because the cable was already in the ground, and the range is adequate for the camera's resolution.
A site migration moves from analogue to IP, and the existing coax is reused with media converters where the distance allows.
Standards and Verification
Analogue video levels and impedance are defined by the video standards applicable to the equipment, and coax performance by the cable manufacturer. Recorder equalisation capability is specified by the recorder manufacturer and is the figure that matters at the limit.
Verification is a visual assessment on the actual recorder plus a signal level measurement where a meter is available. Judging from a laptop capture at the camera end tests the wrong link.
Rule out the ground loop before replacing cable. It is the most common misdiagnosis at distance, and no amount of better cable fixes it.
The Conversion Option
Where the distance exceeds what coax and the recorder can handle together, a video balun pair converts the signal to twisted pair and back, which often extends the range on cheaper cable.
The trade is that a balun pair introduces its own loss and requires the pair to be of reasonable quality, and the baluns must match each other.
For new installations at long distance, IP cameras over Ethernet or fiber are usually the simpler answer, because the distance question is resolved by the network rather than by the video signal.
Documenting the Limit
Record the recorder's equalisation setting for each channel at commissioning. It is a number that changes and, when it does, it indicates degradation in the run.
A setting that creeps upward over months is tracking a cable that is slowly failing, usually through moisture at a connector.
That record turns a subjective judgement about picture quality into a trend that can be acted on before the camera drops out entirely.
Photograph the equalisation screen at commissioning and keep it with the camera schedule, which is where someone will look when a channel is questioned.
Where a channel is marginal, test it with the camera on a short lead first. That single step separates a camera fault from a cable fault in minutes.
Related reading: Coax cable signal loss — blogs/news/coax-cable-signal-loss
Related reading: Siamese coax cable — blogs/news/siamese-coax-cable
Related reading: Coax cable vs fiber — blogs/news/coax-cable-vs-fiber
A hum bar is not a distance problem. It is a ground potential difference, and better cable will not remove it.
Frequently Asked Questions
How far can analogue CCTV run on coax?
Typically a few hundred metres on RG59 and further on RG6, but the recorder's equalisation capability is the real limit.
Is RG6 better than RG59 for CCTV?
Yes for longer runs, because its lower loss preserves the higher video frequencies that carry detail.
Why does my long run show hum bars?
That is a ground potential difference between buildings, not cable loss. Use a balun pair or fiber to break the loop.
When should I stop using coax for CCTV?
When the required distance exceeds what the recorder can equalise, or when the camera resolution justifies moving to IP.
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