RG6 Aluminum Braiding with Aluminum Foil

[sexydadee 0]

Please explain to me the immediate and longterm consequences of using this cable for CCTV, because I cannot understand how this one installer is getting away with installing this cable, even on long runs (300meters) and still get a decent video. I forgot to mention that it is a copper-clad steel conductor

[survtech 0]

The primary problem will be the DC resistance of the cable. Comparing two Belden RG59/U cables, for instance:

Belden 1426A and 8212 have very similar specs except the 1426A has a pure copper center conductor while the 8212 has a copper-clad steel center conductor. The DC resistance of the 1426A is 10 ohms per 1000 feet while the DC resistance of the 8212 is 44.5 ohms per 1000 feet. This will cause the video signal to attenuate faster in copper-clad steel cable, reducing the length you can run before the picture is affected.

 

When you add the factor of "skin effect", where low frequencies travel in the center of a conductor but higher frequencies tend to travel in the outer area, the result of using a copper-clad steel cable will be a higher attenuation of the low frequency components of the video. This can cause poor sync stability and exaggerated high frequencies which usually affects the color signal.

 

Both of the above examples have woven copper shields. The DC resistance of the copper shield material is 2.6 ohms per 1000 feet. Belden 1186A is similar to 8212 except it has an aluminum shield. Its shield's DC resistance is 7 ohms. This will even further limit distance capabilities.

 

While RG6/U would experience less loss overall due to its larger center conductor (18 gauge versus 20 gauge), it will still attenuate the signal faster than copper/copper RG59/U. An example would be Belden 1189A, which has 18 gauge copper-clad steel center conductor and aluminum foil shielding. The center conductor is 28 ohms per 1000 feet and the shield is 4.8 ohms per 1000 feet; not nearly as good as the 1426A RG59/U.

[sexydadee 0]

basically, i will be seeing washed out colored video?

[survtech 0]

It could be, but you also may see the video jitter and/or lose sync. It depends on a number of factors: the length of the coax, the output of the camera, the sensitivity of the monitor or DVR, etc. In some instances, it may not be very noticeable unless you A-B compare the camera with a short run or the correct cable type versus a the same camera with a long run of incorrect cable.

[hardwired 0]

Foil shield cable is also more likely to pick up interference from low frequency interference (60Hz from lights/transformers/running parallel with high voltage wires, etc.) than copper braid cable.

 

RF signals that are normally carried on foil cable are not usually affected by that type of interference, it is easily filtered in RF equipment, but baseband video (DC-15Mhz or so) will be affected.