Maximum transmission distances for digital video cables

The serial digital interconnect standards are designed to operate where the signal loss at half the clock frequency does not exceed the approximate loss values:

These differing standards explain why the maximum transmission length at 6G (UHD 4K dual link) is greater than for 3G.

This provides a method of defining the maximum calculated length of cable for satisfactory signal transmission. Interfaces such as connectors and patching may alter the overall "end-to-end" parameters as the cable is only one part of a signal path, and this also assumes installation of cables within their minimum bending radius limits and without crush effects of tie-wraps and other cable bindings that locally distort the construction profile. Having mentioned "the disclaimers", the values shown below are a reasonable guide to what might realistically be expected in a typical professional installation.

However, these figures are the minimum distances, according to the relevant SMPTE standard. In practice, particularly with 12G, newer receiver equalisers can recover signals below the minimum levels defined in the standard, and thus enable longer run lengths. This will vary from device to device connected, and so cannot be quoted here. The bit error rate (BER) can vary dramatically as the calculated distances are approached. The BER is dependent on the receiver design and the losses in the actual coaxial cable used. Where applications are near the maximum distances shown in the table, it is recommended that distribution and routing equipment manufacturers should be contacted to verify the maximum recommended transmission distances.