EverFocus HD-CCTV EPHD08 - Manual (Page 17)

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Well known signal parts such as Sync, Burst and others do not exist here.
The high frequencies do not allow a signal evaluation by standard oscilloscopes or other standard video
measurement tools. Only quite expensive HD-SDI analyzers and upscale HF - oscilloscopes could be used
here. In most cases such equipment is not available at installation site.
For this reason a careful specification of the cable type is mandatory for system planning, especially in
applications with long cable distances.
2.1.3 Cable types
The short description of HD-SDI signals above explains, why high frequency attenuation of the used video
cable has a high influence on the achievable maximum cable length. Further on also the Return Loss of the
coaxial cable and plug influences signal stability.
The standard RG-59 cable types - the most common in the CCTV industry - are originally designed for
lower frequencies.
However, due to the new optimized receiver interfaces of EverFocus HD-CCTV equipment it is also
possible to use standard RG-59 cable for distances of over 100m.
High quality, low loss RG-59 cable types allow distances up to 160m.
Longer cable distances can be achieved with low loss RG-6 or RG-11 type coaxial cables.
Generally are cable types with 75 Ω impedance required.
Attenuation at 1 GHz: < 32 dB per 100m (328 feet)
Return Loss attenuation: > 20 dB
Impedance: 75 Ω
The table below gives an orientation for achievable cable distances:
Cable Type Attenuation in dB at 1
GHz per 100 m / 328 ft
Max. Cable distance in
m ft
RG-59 24 ~ 40 * 70 ~ 160 230~520
RG-6 15 ~ 35 * 100 ~ 190 330~620
RG-11, CATV-
lowloss cables
8 ~ 16 * 180 ~
<
250 590~<820
* Low quality cable may have higher attenuation