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Thread: Introducing NBN HFC into existing cabling with Satelitte Foxtel and Free-to-Air (how)

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    Default Introducing NBN HFC into existing cabling with Satelitte Foxtel and Free-to-Air (how)

    We have a building that currently has Foxtel satellite and Free-to-air TV and are available for NBN HFC. It is a 4 storey building with an MDF in the basement and one unit per floor.

    The building coaxial cabling layout can be found here:


    Here is an edited copy showing more clearly what is in the MDF, what is in the hallway cupboard in each unit and what is at the outlet in each unit:


    All cabling from MDF splitters onwards is RG6.

    We would like to avoid installing a new cable from MDF to each unit for NBN HFC as it would be very costly. NBN will install HFC into the MDF then have advised its up to us to get it to each unit.

    So far my thinking is:
    Combine the FTA with the Sat-V at the MDF, after the FTA and Sat-V leave their respective amplifiers. Send the combined signal through the Sat-V splitter and cabling to each unit. We can then use the FTA RG6 (which is now not being used) to get NBN HFC from the MDF to the cupboard in each unit.

    If this is the case, it is when the signals get to the cupboard that Im not sure about. Can the combined signals (of Sat-V and FTA) go through the Multiswitch and then the FTA and Sat-V would arrive at each of the 3 x Sat-V outlets in the unit, and then we would need 3 x uncombiners in each of the units (1 in each room on the Sat-V outlet which the Sat-V and FTA cables would plug into the uncombiner). Also, if we do it this way, on the NBN HFC that has now arrived at the cupboard on the old FTA RG6, can we install a 3way splitter in the cupboard so the NBN HFC signal arrives at all 3 of the NBN HFC outlets (that were previously FTA). Obviously only one would be used at any time though would allow the customer in the unit to move the modem if they chose.

    If the combined FTA and Sat-V signal cant go through the multiswitch for any reason, I guess we would need to uncombine them in the cupboard before they go through the multiswitch. This would mean the FTA would then have to run to each of the 3 outlets on the current FTA RG6's and the NBN service (and the modem) would be stuck in the cupbaord) which is not preffered but if there is no way around it at least we have the NBN HFC service into the unit cupboard and we can go from there.

    Would love any thoughts or recommendations.



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    i wish you luck never seen this type of multiplexing and suspect that the cross mod will stuff the lot and nothing will be coaxial any more . the signal from the dish is not digital and the nbn is ??? therefore there is no way that they can be combined that i know off, never seen a uncombiner ????

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    I wouldn't have designed the existing distribution system that way to begin with.

    You haven't mentioned telephone cabling in the units, which will need to all connect to the NBN modem.

    The best method would have been to use cascadable mutiswitches which combine terrestrial and satellite signals, which then become available on all outlets.

    You then just use a sat/terrestrial diplexer in reverse at the unit wallplates (or on flyleads) to separate the bands and connect to the applicable devices.

    You could replace the existing mutiswitches with combining types, or you could combine FTA and satellite signals with diplexers, but only after the outputs of the existing satellite multiswitches.

    You most likely couldn't combine the bands prior to the input of the existing multiswitches, as they may only pass satellite frequencies.

    You haven't provided the specs on the multiswitches to give you a definitive answer, but I suspect they are satellite only.

    The same separation as you mentioned will then work, with a FTA/sat diplexer in reverse at the outlets.

    You have to be able to balance all signal levels of course.

    That will free up the existing terrestrial RG6 cable runs as you suggested, for exclusive NBN use.

    Yes, you could use an appropriate splitter in the units for the NBN.

    As I mentioned, you'll still need to connect any unit telephone cabling to the NBN modem.

    EDIT: Didn't look at the second diagram before, so the above won't work, because the multiswitches are in the units themselves.

    All you could possibly do with the current design is to combine the FTA onto one leg of the satellite with a diplexer at the MDF after the amps, as you mentioned, then separate the signals again prior to the multiswitch in each unit, assuming the multiswitches are for satellite only.

    The separated signals would then go to the multiswitch input for satellite and the FTA to the FTA splitter, with another diplexer on the output of the FTA splitter to re-combine the signals after the multiswitch onto one leg and separated again at the wall plates (or flylead).

    The result would be satellite H/V at the wallplates with one of those legs also carrying the FTA and the connection previously used for FTA would now be available for NBN.

    The problem is all that splitting, combining and separating may create significant system noise, level loss and increased BER.

    I cannot see any method of balancing signals in the current design to counter this, or even to balance levels over the various cable run lengths from ground to top floor.

    What are the present satellite and terrestrial levels, BER and MER currently reading at the launch amps, splitters and tap outputs at the MDF, inputs to the multiswitches and splitters in the units and at each of the wall outlets?
    Last edited by mtv; 29-05-18 at 11:03 PM. Reason: added info

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    gotta ask ? is it wired as per diagram if so then its got real grunty line amps in it .
    Have you physically checked the wiring your self ?

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