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TV antenna amplifier power injector

Discussion in 'Electronic Basics' started by eug k, Jun 17, 2006.

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  1. eug k

    eug k Guest


    I'm trying to hook up an active antenna that needs 5V at 30ma to be fed
    thru the coax, to a tuner that doesn't provide that power. I'm
    assuming I would be able to just hook up a 5V supply (from a USB
    socket in this case) to the coax, with a capacitor between the centre
    conductor and the tuner input.

    Will this affect anything adversely? Is there a better way to do it?
    I wouldn't expect the weak RF signal to affect the computer much, but
    who knows. :)

    The antenna will be mounted indoors near a window so lightning or
    surges shouldn't be too much of a problem.

    I thought of modifying a 2-way passive splitter for this purpose.
    What cap should I use?>

    I'd like to receive VHF and UHF, from 170-230MHz and 500-600MHz.
    It's a digital TV receiver if that makes a difference.

  2. Phil Allison

    Phil Allison Guest

    "eug k

    ** The 5 volt DC power MUST be fed onto the co-ax via an RF inductor.

    This is to isolate the PSU from the RF signal.

    A value of 5uH should be OK.

    ......... Phil
  3. eug k

    eug k Guest

    OK.. what about the capacitor?

  4. Phil Allison

    Phil Allison Guest

    "eug k

    ** Use any 1nF cap that fits.

    ...... Phil
  5. Guest


    Keep the inductor lead which connects to the RF path very short.

    steve balstone
    stephen balstone
  6. ehsjr

    ehsjr Guest

    What inductor? Why keep the inductor lead short?
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