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Thread: Best Pre-amplifier level for Kingray DW42

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    Default Best Pre-amplifier level for Kingray DW42

    Hi all,
    I am new to this forum and would appreciate help with using Kingray DW42 (Specs below)
    I am using a reverse splitter arrangment to combine:
    FTA - typically 35-40dBuV
    2 x 2 Ch HDMI>RF modulator set to about 40dBuV
    Sky Decoder 80dBuV (fixed) attenuated to 40dBuV



    With the UHF gain of the DW42 set to minimum, the output levels on the output of an 8 way splitter (after the amp) are above 75dBbuV but are further split so would fall in range at the TV's (in fact end up around 55dBuV).
    My question is , what is the best level to achieve pre-apmlifier based on the specs below, and if it is to be attenuated, would it be prefereable to
    attenuate before or after the DW42?
    Aprreciate any helf here?

    Frequency Range
    VHF Low: 40-144 MHz, VHF High: 174 - 300 MHz, UHF: 470 - 860 MHz

    Maximum Gain
    VHF Low: 35 dB, VHF High: 37 dB, UHF: 40 dB

    Gain Control Range
    VHF Low: 20 dB, VHF High: 20 dB, UHF: 20 dB

    Maximum Output Level
    118 dBμV @ - 60 dB IMR (DIN45004B)

    Noise Figure
    < 6 dB



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    Default

    You haven't mentioned if you actually have a signal problem or not with the configuration, however, the quoted FTA signal level of 35-40dBuV is too low. Why?

    All input levels to the distribution amp should ideally be around 65 dBuV and arriving at the outlets around the same level, so you really need an individual channel amp headend/combiner to balance all input levels prior to the distribution/launch amp.

    You should only attenuate signals at the input of a distribution amp if they are too high, (causing over-saturation etc). Adjust the amp output/splitter/tap cabling configuration to obtain the desired level at the furthest outlet point and (if required) attenuate others to match.

    What are the BER/MER figures at each stage of distribution?

    If you are having signal issues at the outlets, a diagram of the distribution chain, noting signal levels and BER/MER measurements at each stage would be helpful.

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    Thanks mtv,

    I've used the (analogue) modulator combiner before (Kingray) comes in 6 and 8 channel.

    So I need to present at the amp @ 65dBuV, that's the answer I needed.

    i didn't think the 65dBuV was essential before the amp.

    I will try an active combiner first, or get the FTA antennae upgraded as it's fringe area and possibly need a higher gain FTA Antennae.

    BER/MER levels are in range and all FTA channels are fine.

    I have an issue with a SKY T-MOD decoder dropping its SD channels 600-603 but maintains it's HD channels 350-360. (strange, usually HD would fail first?)
    I have no LCN conflicts and I think it's a subscriber issue on the sky decoder than anything else.

    I just have a tech coming from Sky and I don't want to be embarrassed by poor levels.

    A renovation is eminent , so everything will be done from scratch, and I can balance splitters properly.

    I know they're all over the place now :-)

    Thanks again for your input!

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    BTW,

    Sky got into the decoder and fixed it remotely ... so it was a subscriber issue!

    I will balance the system properly moving forward. Regards

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    Hard to advise without seeing a complete setup including cable type, distances etc.

    Ideally though. You want to get all the input levels fairly even before you launch, otherwise your modulated signal can affect the signal quality
    on your FTA.

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