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:

SMPTE 259M (PAL, widescreen): Maximum length = 30dB loss at half the clock frequency
SMPTE 292M (HD-SDI 1080i): Maximum length = 20dB loss at half the clock frequency
SMPTE 424M (HD-SDI 1080p): Maximum length = 20dB loss at half the clock frequency
SMPTE 2081 (UHD 4K dual link): Maximum length = 40dB loss at half the clock frequency
SMPTE 2082 (UHD 4K single link): Maximum length = 40dB loss at half the clock frequency

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.

Data rate: 270Mb/s 1.5Gb/s 3Gb/s 6Gb/s 12Gb/s Construction (1,2)
Specification: SMPTE 259M SMPTE 292M SMPTE 424M SMPTE 2081 SMPTE 2082
Application: Component 4:3 1080i HDTV 1080p HDTV 2160p30 2160p60
Max. attenuation (4): 30dB 20dB 20dB 40dB 40dB
Belden 1505F 263m 68m 46m 60m 0.8L/3.7 flex
Canford SDV-F 285m 80m 51m 61m 43m 1.0L/4.8 flex
Canford SDV-F-R 285m 80m 51m 61m 43m 1.0L/4.8 flex
Canford SDV-XF 285m 80m 51m 61m 43m 1.0L/4.8 flex
Belden 1694F 319m 85m 57m 69m 1.0L/4.6 flex
Canford SDV-F-HD 323m 94m 63m 74m 50m 1.2L/4.8 flex
Belden 4694F 373m 96m 65m 87m 56m 1.0/4.6 flex
Belden 179DT 127m 36m 25m 35m 0.3/1.4
Canford SDV-M 127m 44m 33m 45m 31m 0.41/1.9
Canare L-3CFB 257m 68m 46m 42m 0.65/3.1
Belden 1855A 236m 66m 46m 63m 0.585/2.59
Belden 1855ENH 261m 74m 52m 71m 0.6/2.8
Belden 4855ENH 272m 76m 54m 75m 51m 0.6/2.8
Canford SDV 227m 66m 47m 65m 45m 0.6/2.8
Canford SDV-LFH 227m 66m 47m 65m 45m 0.6/2.8
Canford SDV-X-LFH 258m 70m 51m 66m 46m 0.6/2.8
Canford SDV-LFH-Cca 258m 70m 49m 66m 46m 0.65/2.8
Canford SDV-UHD-LFH 258m 74m 50m 72m 49m 0.7/2.9
Canare L-4CFB 310m 82m 55m 52m 0.8/3.7
Belden 1505A 330m 92m 64m 87m 0.8/3.7
Belden 1505ANH 330m 92m 64m 87m 0.8/3.7
Canford SDV-I-X-LFH 327m 90m 64m 86m 56m 0.8/3.7
Belden 1694A 408m 113m 78m 105m 1.0/4.6
Belden 1694ANH 408m 113m 78m 105m 1.0/4.6
Belden 4694ANH 426m 118m 82m 114m 79m 1.0/4.6
Canford SDV-L 386m 109m 75m 104m 70m 1.0/4.8
Canford SDV-L-LFH 386m 109m 75m 104m 70m 1.0/4.8
Canford SDV-L-LFH-Cca 404m 111m 76m 104m 70m 1.0/4.8
Canare L-5CFB 420m 112m 76m 68m 1.05/5.0
Canford SDV-L-X-LFH 424m 115m 80m 107m 71m 1.0/4.8
Canford SDV-L-UHD-LFH 487m 127m 91m 129m 87m 1.2/4.9
Belden 7731A 637m 177m 119m 161m 1.6/7.2
Belden 7731ANH 637m 177m 119m 161m 1.6/7.2
Belden 4731ANH 649m 182m 126m 173m 117m 1.6/7.2
Canford SDV-HD 662m 175m 118m 152m 107m 1.6/7.3
Canford SDV-HD-LFH 662m 175m 118m 152m 107m 1.6/7.3

Notes

  1. This is of the format: Centre wire diameter (mm) / Dielectric diameter (mm). Note that ‘L’ denotes a stranded centre wire.
  2. For stranded centre wire designs for flexible applications, there will be less copper cross-sectional area than a solid conductor of the same diameter. The centre wire or bunch diameter is relevant for connector choice. Less copper means a greater signal attenuation and hence shorter transmission distances.
  3. Belden do not publish maximum transmission distances at 12G for legacy digital cables. They only recommend the newer 4xxx series for 12G. Canare do not provide data for 6G.
  4. There may be small variations in attenuation figures between manufacturers due to the testing equipment used, particularly at the higher frequencies. This means that there can be small variations in the maximum transmission distances quoted, which are derived from the attenuation figures.

The above information has been provided by Belden Europe, Canare and Draka-Prysmian (manufacturers of the Canford SDV series cables).

SDV™ and LFH™ are registered trademarks of Canford Audio Limited.