Page 1047 - 5G Basics - Core Network Aspects

Transport aspects 2

Both diplexers have identical characteristics. There are typically no splitters or bridged taps in the G.fast
path. There are no in-line amplification devices in the G.fast or satellite signal path. The signals at the
Satellite port reside at 2.3 MHz and 950 to 2150 MHz.
Typical diplexer characteristics from G.fast port to Common port:

Passband: 0-0.5 and 5-806 MHz
Insertion loss: 5 dB from 30 kHz to 500 kHz
4 dB from 4 to 5 MHz

2 dB from 6 to 7 MHz
1.5 dB from 6 to 212 MHz

2.5 dB 212 to 806 MHz
>40 dB out of band
Return loss with all ports terminated with 75 Ohms: 10 dB

The coaxial cable signal loss characteristics in dB per 100 m are shown in Table X.19.

Table X.19 – Insertion loss characteristic of coaxial
cable types [b-Freeman].

RG-59 RG-6 RG-11
1 MHz 1.31 0.66 0.66

10 MHz 4.59 1.97 1.31
50 MHz 5.90 4.59 3.28
100 MHz 8.86 6.56 5.25

200 MHz 11.81 9.18 7.54
400 MHz 16.07 14.10 11.48
700 MHz 22.63 18.37 15.42
900 MHz 25.58 19.68 17.71

1000 MHz 27.22 20.00 18.37
2150 MHz 39.69 32.47 21.65

IL (dB)/ 100 m
The maximum distance of the deployment is modelled by RG-6 coaxial cable as shown in Figure X.5. A
longer deployment distance is possible by utilizing the lower loss RG-11 coaxial cable. Conversely, the
maximum distance could be reduced with RG-59 coaxial cable to the equivalent loss distance of the RG-6
coaxial cable.
In order to assist the simulation and modelling of the coaxial cable insertion loss characteristics for typical
DMT frequency grid, the exponential approximation formula is provided below.
f = frequency in MHz
b
IL = a×f + c×f + d (dB/100 m)

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