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Thread: Help: How to mix DTV signal with RF signal for TV reception

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    Default Help: How to mix DTV signal with RF signal for TV reception

    Does anyone know a mixer or a Two_In-One_out device that can input both digital tv (DTV) signal and RF signal then output for TV?

    I have an array of analogy modulars that convert satellite tv signals into RF channels. RF channels were then combined by a combiner (16 in 1 out) into one signal, amplified by an amplifier then sent to rooms for TV reception. I'd like to do this to my digital tv signal, however, when I connect DTV signal to the combiner, the DTV signal simply disappeared as it won't take by the combiner. The amplifier can take the DTV signal no problem. Hence, I need a combiner, or a mixer that can take both DTV and RF analogy signals. Can you help?

    Tez

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    What exactly are you trying do combine... Foxtel and terrestrial?

    From your description, your best solution would be to transcode the satellite receivers (AV... HDMI is best) into DVB-T, then using channel amps to balance all levels prior to the distribution amps.

    This is the basic method of SATV/MATV signal distribution systems.

    If you are distributing RF to ordinary TV's, it's false economy using analogue modulation, given that most manufacturers are ceasing building TV's with analogue tuners.

    You need to provide a distribution system design plan, noted with signal measurements at various distribution points etc.

    It's a complex balancing act and there's no single answer, without knowing specifics.

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    The source is from AsiaSat 7, which are decoded into AV signal then converted to RF signals. These RF signals are then combined into one single RF signal for amplifying. I'd like to combine this signal with DTV signal for TV receptions.
    Already have old tvs ready for use (decoding both DTV and RF), so I am not worried about reception end.
    The purpose to do this is to save set top boxes and RF modulars, and deliver 28 DTV programs in one go and at HD format. This compares with converting/modulating the channels one by one and at SD format.
    Last edited by tanshm; 10-04-18 at 07:27 PM.

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    Quote Originally Posted by tanshm View Post
    The purpose to do this is to save set top boxes and RF modulars, and deliver 28 DTV programs in one go and at HD format.
    Analogue is not capable of HD, so you'll have to convert to digital.

    As I mentioned, your best option is to either modulate HDMI output of the satellite decoders into DVB-T or better still, use transmodulators (no set top boxes required) to convert the satellite DVB-S/S2 signals to DVB-T.

    Use channel amps to balance and mix the FTA terrestrial and modulated/transmodulated DVB-S/S2 prior to the launch/distribution amps.

    There's a heap of equipment available to do this, but there's no such thing as 'plug 'n' play that you seem to be looking for.

    Plenty examples of the equipment you need to do the job right... but you'll still need instrumentation to adjust it all correctly.


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    As per my previous post:

    You need to provide a distribution system design plan, noted with signal measurements at various distribution points etc.

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    The distribution system, or routing was designed and set as all equal to each units then to 4 rooms in each unit. Don't know how to measure them, but I will see if there are any issues. I have two outputs from the amplifier to use, each at a different level, if the signal is too weak or too strong.

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    Quote Originally Posted by tanshm View Post
    Don't know how to measure them,...
    What you are trying to achieve is not that simple.

    Especially with digital signals, as it's very easy to upset BER/MER with other RF, so you must ensure all signal levels, BER/MER,C/N etc, are all within operating parameters.

    It really needs instrumentation so you can 'see' exactly what every individual and combined signal is doing.

    If you don't know how (and likely don't have the necessary equipment) to measure and balance signals, I highly recommend you engage someone with the knowledge, experience and equipment to do it for you.

    It's a lot more complex than just buying a particular combiner/mixer.

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    If there is no simple mixer can do this job, then it is a pity. Thanks anyway.

    Just can't imagine that, and tried it at home, the cable carried the combined RF signal is actually carried some weak DTV signal from the air and my home tv can actually scan about 10 digital signals, plus the RF channels. The natural can do it, but our human can't! And an old satellite receiver has an antenna in and out ports, can also transfer all DTV signal to TV, while send its own RF signal to TV at the same time. There should be an easy way to do this.
    Last edited by tanshm; 11-04-18 at 02:52 AM.

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    One on each end!


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    Quote Originally Posted by cmangle View Post
    One on each end!

    Incorrect.

    The OP is wanting to mix modulated AV signals from an 'array' of decoders with terrestrial RF... not mix satellite I.F. with DVB-T.

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    ah ok, mtv . . . something like this?




    Last edited by cmangle; 11-04-18 at 02:36 PM.

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    Quote Originally Posted by cmangle View Post
    ah ok, mtv . . . something like this?




    That device is for cable.

    Their description is also misleading. Composite video cannot carry HD.

    I don't think you are understanding the OP's requirement fully..... deliver 28 DTV programs in one go and at HD format.

    The OP hasn't provided a diagram of the distribution system, has not provided frequencies in use or intended to be used, or any signal measurements, so it's extremely difficult to give specific advice.

    With any MATV system, especially one that combines modulated AV, it's imperative to balance levels.

    The OP has stated they want HD distributed... so any modulators/transmodulators must be digital to achieve that.

    Mixing analogue AV modulators with DVB-T will not do what he is asking.

    I get the feeling the OP doesn't understand this either.

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    Default What inputs are here?

    What inputs are here?
    Quote Originally Posted by cmangle View Post
    ah ok, mtv . . . something like this?
    Last edited by tanshm; 11-04-18 at 07:56 PM.

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    I have used Channel Plus equipment to assign RF channels to AV sources and loop one right after the other from multiple sources.

    Lets say Terrestrial Antenna channels cease at ch 65 ( Vhf lo-hi 3, 6, 10 , 12, - UHF 17, 29 , 48 and 65)!

    You would use the Channels plus gizmos to assign upper channels to the various sources, say 84 86 88 92 96 etc! and they all would appear on one coax cable!
    Last edited by cmangle; 11-04-18 at 02:42 PM.

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    The RF signals are from S2=112MHz to Z65=823MHz but missing the DTV frequencies in between; RF using B/G system but channels jumping by two, e.g. S2, S4 and no S3 and S5. DTV signal is believed from 571 to 606MHz from the local TV transmitter. IN theory, they won't be at the same frequency for any two channels.

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    Where are you located?

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    Quote Originally Posted by mtv View Post
    Where are you located?
    In a remote area of WA.

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    Without the DTV signal, the system is as below:
    Satellite to 8 channel decoders*5; to 4 channels RF modulars *10; to 16 in 1 out combiner; to amplifier; to splitting network; to 40 rooms.
    Just want to add the DTV signal to the above system. Prefer at the front of the amplifier. But I can buy a second amplifier, if required. The alternative is to use a number of set top boxes; AV signal to RF modulars...but this is not ideal.
    Last edited by tanshm; 11-04-18 at 07:53 PM.

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    Quote Originally Posted by tanshm View Post
    Without the DTV signal, the system is as below:
    Satellite to 8 channel decoders*5; to 4 channels RF modulars *10; to 16 in 1 out combiner; to amplifier; to splitting network; to 40 rooms.
    Just want to add the DTV signal to the above system. Prefer at the front of the amplifier. But I can buy a second amplifier, if required. The alternative is to use a number of set top boxes; AV signal to RF modulars...but this is not ideal.
    How many rooms total are you trying to install this setup too ?

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    40 rooms, say it again here.

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