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Thread: Triax DDU 333112 Domestic Distribution Unit

  1. #1
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    Dec 2015

    Default Triax DDU 333112 Domestic Distribution Unit

    Triax DDU 333112 Domestic Distribution Unit

    These units have a few oddities so I thought a review would help.
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    The first one is that the signal from the UHF inputs, the TV signal from the areal, ONLY goes to the "Down Link".

    I set up the unit and did not get the TV signal from the "R/TV IR-LINK" or the R/TV SAT outputs.
    Connecting the TV areal to the "UP Link" input/output does send the signal to the outputs.

    NOTE: the "UHF 1" input sends out 12 Volts DC for the masthead amplifier to use. The "UHF 2" input does NOT have a DC voltage.

    It seams the unit is set up for all the input signals to go to the "Down Link" and be used there for redistribution back up the "Up Link".

    NOTE: The R/TV IR-LINK" outputs also output a DC voltage for the remote control inputs to use.
    These outputs are designed to have a IR sensor for each TV to control the master unit at the "Down Link".
    To use these outputs for a standard TV you will need to add a DC blocker on each port to stop the DC voltage from reaching the TV.

    The "SAT 1" "SAT 2" "SAT 3" and "Sat 4" inputs pass through the unit directly, ie "Sat 3" outputs to "R/TV7 SAT 3".
    You connect the dish to "Sat 3" and the set top box to "R/TV7 SAT 3".
    These input / outputs are NOT switched, like a DiSEqC switch, they just pass through.
    As the satellite signals and LNB voltage pass through the other signals are added to the cable.
    This means you can use a signal splitter at the STB to split out the UHF TV signal from the same cable.

    Traix make wall flush plates for this purpose.
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    This wall plate has two cables attached, one from the "Down Link" and the other from the "UP LINK IR-SAT 2".
    The UHF TV signal is on the TV output and I looped that through a splitter to the "Return" to feed the UHF TV signals to the other outlets on the DDU.
    The "SAT 1" and "SAT 2" outputs are connected through the DDU to the LNB / Dish connected to the DDU inputs "Sat 1" and "Sat 2".

    So with the new DVB-T sender I have, I feed an extra DVB-T channel into the house TV areal cable network and a separate feed to the sleep out.
    I also use the same cables for UHF TV and satellite.


    PS: I have 3 of these and only use one.

    30 July 2017:
    I removed this DDU unit.
    I found that different satellite boxes were interfering with each other through the DDU.
    With one sat unit / LNB circuit passing through the DDU, the frequencies at the 950MHz end are passed to the other satellite / LNB circuits.
    This means I could scan in the BBC TP (4161 V) off of Intelsat 19C Band with the other sat unit, if that I19C LNB circuit was powered on.
    Any common frequencies then clashed and went "No Signal"

    This shows the frequency separation that the unit is listed to provide between Terrestrial and satellite overlaps and the satellite frequencies are passed from one satellite circuit to the next via the terrestrial circuits.
    The top frequency for terrestrial is 850MHz and the lowest for satellite is 950MHz.

    I ran more cable for a separate UHF Terrestrial circuit.

    The DDU would work fine if all the satellite feeds (all four) were from the same satellite. I think this is what it is made for.
    Frankly a few signal splitters to combine DVB-T and DVB-S signals down the same cable would be a lot less hassle.
    It is possible that the unit I was using got zapped by the electric fence earth currents that occasionally kill my switches.
    It did this cross over interference from day one after I installed it.

    Last edited by Feralkiwi; 30-07-2017 at 02:51 PM. Reason: Added info

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