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Digital vs analogue antenna for FM radio

Discussion in 'Hobby Electronics' started by L.A.T., Jul 25, 2007.

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  1. L.A.T.

    L.A.T. Guest

    We live in the bush, and digital broadcasting is new. For years we have had
    satisfactory VHF and UHF TV reception from a two-piece antenna ( a wide one
    and a skinny one connected via a junction box.). The FM receiver is also
    connected to this antenna and is satisfactory as well, even though the VHF
    part of the antenna is looking a bit droopy.
    When we connected a STB to one TV and bought a TV with its own digital
    tuner, they both worked spectacularly well connected to the existing
    antenna. Now that we don't have any analogue TVs, we are thinking of
    replacing the drooping antenna with what we are told is all we need for
    digital reception, a very small thing that looks like a grill . If we have
    to do this, is its construction such that it will give us FM as good as we
    are getting now? I wish we could take the installer's word for it, but I
    don't really think he knows much more than I do.
     
  2. If the present one works I would seriously consider refurbishing it.
    Antennas have a "catchment" area. And generally, smaller antennas have a
    smaller "catchment". A standard beam antenna with correct element size
    is probably the way to go. I'm a bit doubtful about the FM receiver
    getting good reception off a UHF antenna, since FM radio is in the VHF band.

    Dorfus
     
  3. Phil Allison

    Phil Allison Guest

    "L.A.T."

    ** Beware - all claims made by some turd trying to sell you something.


    ** No way - not at all - no chance.


    ** Why ?

    You in love with the turd?


    ** Get him to put the " grill" thing up - at his trouble and expense.

    If it ain't 100% satisfactory

    - DO NOT PAY ONE DIME.

    Tell him THAT is the deal !!!!!!!!!

    See the little shit slink off .............




    ........ Phil
     
  4. a t e c 7 7

    a t e c 7 7 Guest

    Fact is that "grill" will not on it's own provide similar performance ,
    if you have good reception clean the old unit up and keep using it .
    where are you located ?
    If you want a change for changes sake there may be something specific
    to your area as per recommendation
     
  5. L.A.T.

    L.A.T. Guest

    Thanks for you replies.
    One of the reasons for the change is that we are about to instal rain-water
    tanks. The birds perch on the antenna and crap on the roof. We will move it
    to a different part of the roof where birdcrap won't fall onto the
    catchment, and I thought that we might replace the antenna at the same time.
    Between you all, you have pretty well convinced me to stick with the
    existing antenna.
    There was a story in Radio and Hobbies when TV first appeared (1956?) about
    the rumours and fears about TV. The waves went through you and fried your
    brains. The waves confused the cows and made them give less milk. The waves
    disoriented the ducks and they lost their way. And so on. Then there was the
    chap that insisted that the TV "made the water taste funny." And yes, he had
    installed the antenna above his water tank, and the birds congregated on
    the antenna and crapped directly into the tank
     
  6. Phil Allison

    Phil Allison Guest

    "L.A.T."


    ** ROTFLMAO !!!!!!!!!!!!!

    Love it.

    Best antenna story on this NG in yonks !!!


    ....... Phil


    ( who grew up in Shepparton were the family had a 70 foot high, stacked
    Yagi antenna facing south - to pick up the Melbourne Olympics in
    956 )
     
  7. Pete

    Pete Guest

    Let me get this straight - it's working spectacularly well, and you're
    going to change it? Whatever for? What could you possibly be hoping to
    achieve?

    Peter
     
  8. My new digital TV antenna gives awful FM reception, practically non-
    existent, compared to my previous analog one.

    If your system is working spectacularly well, why change it?

    Dave.
     
  9. Why do they call it a digital antenna anyway?
    Radio signals haven't changed since Marconi and they're still analogue
    by nature. Maybe the bandwidth is different but it's still not digital.

    Anyone?





    Dorfus
     
  10. Phil Allison

    Phil Allison Guest

    "David L. Jones"
    "L.A.T."


    ** DLJ lives in Sydney where DTV in mostly on VHF, unlike rural areas.

    Capital city DTV antennas are sized to suit VHF channels 6 through 12 (ie
    174 to 230 MHz ) plus UHF - hence, they lack response to the 88 to 108
    MHz FM broadcast band on VHF channels 3, 4 and 5.

    Rural area DVT antennas are UHF only - some are " ...a very small thing
    that looks like a grille " - these only cover from 520 MHz upwards.

    So no FM band response whatsoever.....

    But you can get " Dig " and " Dig Jazz " stereo music from the ABC's
    digital TV signal.




    ........ Phil
     
  11. Phil Allison

    Phil Allison Guest

    "Dorfus Dippintush"

    ** Means built to suit just the digital TV broadcast frequencies - plus
    generally they are of lower gain, as DTV works OK with far lower received
    RF levels than analogue TV.


    ** The MPEG compressed video and audio data is modulated onto multiple (
    many hundreds) of close spaced RF carriers such that the result has the
    characteristics of random noise. Bit like when you hear the data stream
    coming from a 56 kb/s dial up modem.

    This makes the pic it immune to ghosting, most interference sources,
    adjacent channel interference problems and noise ( aka "snow" when the
    signal strength gets a bit weak.

    The biggest plus is the dramatic increase in the number of available
    channels at any one location. Each 7 MHz wide analogue channel space now
    accommodates 3 digital pictures and there is no need for channels to be left
    vacant on either side of an occupied one.




    ........ Phil
     
  12. It's called a "digital" antenna because it's designed only for the
    frequency range used by the digital TV stations in your particular
    area, as Phil said.

    You can find out more info about the channels used here:
    http://www.dba.org.au/

    Also, my "digital" antenna is a log-periodic type, like this one:
    http://www.australiandigitaltv.com/accessories/digitalantenna.htm

    Dave.
     
  13. JimW52

    JimW52 Guest

    IIRC the Vikings won most of the gold medals that time around.

    Jim
     
  14. Brad

    Brad Guest

    Same as when colour tv was introduced and the manufacturers sold
    colour antennas. By then the old aluminium was probably 20 years old
    and fed with worn out old 300 ohm ribbon.

    Now, since Digital tv does not operate on Band I or II or 5A, a
    'digital' antenna needs only cover from Ch6 upwards, and also have a
    flatter frequency response from ch6 to ch11A and also therefore has
    poor FM coverage. And once again, it's probably time you replaced the
    old corroded lump that's waving about up on the roof.

    But of course you already knew this and you were being pedantic about
    semantics. Does "digital tv antenna" mean digital "tv antenna" or
    "digital tv" antenna?

    Brad.
     
  15. Brad

    Brad Guest

    Oh, and YES, they have changed since Marconi, especially since he was
    transmitting his first signals using spark. Nothing analog about that!

    Brad.
     
  16. Phil Allison

    Phil Allison Guest

    "JimW52"


    ** Well, they certainly cleaned up all the rowing events.





    ....... Phil
     
  17. Phil Allison

    Phil Allison Guest

    "Brad"

    ** Plus Marconi used Morse code for his radio messages.

    Clearly an early form of digital data.





    ....... Phil
     
  18. LOL!!

    Dave
     
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