can digital get picture if analog TV is weak?

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I have analogue telly at the moment. I use three
antennae for VHF low, VHF high, and UHF going
into a triplexer. Thus I can adjust each one
separately.  The VHF high  (for 7, 9, and 10)
is the problem, probably because the channel 10
transmitter is in a different direction to 7 and 9.
I have moved the antenna all over the place, but
can't get a good picture on all three. After
last attempt I have channel 7 the noisiest, and
if it rains, the picture drops back to black and
white. I can't raise the anntenna any higher.
So I wonder will going digital help?
If the signal is weak and borderline for analogue
TV, will a digital box pull out anything?


Re: can digital get picture if analog TV is weak?


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Impossible to say, it's always a case-by-case basis. But generally you
need a decent analog reception to get digital on your existing
antenna.
Look here to see where your digital transmitters are located:
http://www.dba.org.au/index.asp?sectionID22 %

Sounds like it's time you upgraded your antenna and system
installation anyway. You might even be able to get away with a single
digital antenna.

Once you get digital you won't go back.

Dave.


Re: can digital get picture if analog TV is weak?



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***  that's because  7 & 9  are  UHF

 probably because the channel 10
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***  It  does  not  follow,  that simply  because  you have  a  lousy
analogue  signal, that  a  digital  signal will  be the  same.  In  some
cases  a  non-existant  analogue  signal    will result  in a    digital
signal.
  With  digital there  is  no  such  thing a s good or  bad,  You  ether
have a  signal or  you  don't.

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 *** Define  "Digital"  antenna.  They  don't  exist..
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   ***   why  would  you want  too  ??????



Re: can digital get picture if analog TV is weak?



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  Not quite true.

  It is correct that a "weaker" digital signal will result in intermittant or
sometimes non-existant viewing.

  However a too strong signal can also cause reception problems.  Of course,
this doesn't happen very often, but it certainly has happened here in
Australia when people are close to the transmitters and still insist on using
high gain antennas.

  I'm guessing it comes down to the AGC range of the receiver at the high end
of the scale, likely their analogue receiver was obviously better at handling
high signals than their set top box or whatever.

--
Linux Registered User # 302622
<http://counter.li.org

Re: can digital get picture if analog TV is weak?



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I think your attempting to split  hairs,  and  failing.

FEC  decides if the standard of the  signal  is reproducible.

While I will agree with you  in  part about  high  gain antenna's  it's
still controlled  by  FEC,  and  this also  makes  masthead  amps  obsolete.

Many  people  who  had  a  high gain  antenna,   for  analogue  systems,
retained  that antenna, and  in 99  cases  out of  a 100, it  does  the
job.
 And  some  people will  tell you,  that it's imposable to have a  "too"
strong  signal,  it's also arguable , that  modern  Tuners are  self
regulating in that  regard..  BUT unlike  analogue,  we  have  "Forward
Error  Correction "  which  examens the  signal  long  before it reaches the
Tuner,  Would  you not agree.
                                                                     bassett

 



Re: can digital get picture if analog TV is weak?



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  While FEC plays a part, if the front end is swamped, you're going to corrupt
the signal to the point that FEC isn't going to have much of a chance to do
anything.
--
Linux Registered User # 302622
<http://counter.li.org

Re: can digital get picture if analog TV is weak?



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What you  forgot  to  say,  was that  if and  when the  front end is
swamped, [presumably with  signal  strength,  or  overload  ?? ]  the  FEC
will be unable to  cope  and simply  shut  down.  After  all that's what
it's there  for,  and   please  remember  we  are  using a  3/4
comfigeration  not a  7/8,
                                             bassett



Re: can digital get picture if analog TV is weak?


Hi John, long time no see. Not since the old avtech days.

Re: can digital get picture if analog TV is weak?



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Maybe something has escaped me here, but I was under the distinct impression
that the FEC operated on the data stream, implying the demodulated signal.
That being so, how can it be "examine the signal long before it reaches the
tuner"? So no I would not agree.

Re: can digital get picture if analog TV is weak?



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course,
using
end
handling

I live in a strong signal area, and I always find the reverse to be true.

MrT.



Re: can digital get picture if analog TV is weak?


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A "digital" antenna is one designed only for the channels used by
digital TV, and those *do* exist. Perhaps they should be called
"digital band" or something to avoid the stupid semantic arguments.

My "digital" antenna is is not only designed just for the digital
channels, but it's a log-periodic design too which can give an
improved signal and better noise immunity in some situations. Much
smaller and nicer looking than my old "analog" band yagi antennas.

Dave.


Re: can digital get picture if analog TV is weak?



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There is simply no correlation between Analogue and Digital signals
so the digital results depend on many other things than what
your analogue signals are like.

As a generalisation if you have a snowy analogue signal with
ghosts then the probability is that you will get digital.

The original poster does not say which city he is in but 7 and 10
analogue come from the same site in Sydney with 9 analogue from
another site and ABC from the 3rd Gore Hill site.
9 digital comes from the same site as the 9 analogue signals
while 7 and 10 digital come from the same site as the analogue at
times and from the 9 site at others.
ABC digital comes from the same site as the analogue channel 2
and SBS analogue comes from Gore Hill while the digital usually
comes from the 7 10 site.

As far as Basset's assertion that 7 and 9 are UHF thats patent
rubbish.

It will be instructive if the poster tells us which city he is in and
then we may be able to give some real advise instead of the useless
answers so far.



Re: can digital get picture if analog TV is weak?



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Most  charming, I'm  sure,  I have a  little  60inch  tellie  in the
kennel,
It  has a  three way  tuner channels  7,.9, SBS are  tuned  via the  UHF
tuner,  Channel  10 is  VHFH  and  ABC is  VHFL
  and the other thing you  got  incorrect is all  my  rubbish is  patented.
So  hands  up all those who invited this  fuck-wit, to answer.

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 You  of  cause include  your  own answer,  one would assume
   Next,
                                                      bassett
 



Re: can digital get picture if analog TV is weak?



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which means in your location you are tuning to UHF repeaters of 7 & 9. This
may be the case in your location, and is the case in most of regional
australia, but in every eastern capital (and possibly adelaide & perth but
haven't checked), 7 & 9 are broadcast on channels 7 & 9 respectively which
are located in the VHF-H band.
In some locations where geographical conditions prevent reception on the
main channels, repeater stations have been set up on UHF channels. They
can't set up the repeaters on the main channel because it would cause
interference. The actual frequencies used will vary depending on what
channels are available in the location and depending on what channels are
used by adjacent regional stations.
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Re: can digital get picture if analog TV is weak?



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FYI, Adelaide's main analogue transmitters (near Mt. Lofty) are all VHF,
except for SBS which is UHF ch 28. The analog VHF is on channels 2, 7, 9,
10, but there are UHF repeaters in the CBD, mainly for those in the shadow
of the hills. Digital is also VHF from Mt. Lofty, on channels 12, 6, 8 and
11 for ABC, Seven, Nine and Ten respectively. I think SBS digital is UHF
like their analogue and the digital repeaters in the CBD are all UHF.



Re: can digital get picture if analog TV is weak?



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This

Impossible while they are still transmitting analog signals on those
frequencies.
AFAIK, SEVEN transmits digital on ch6, NINE on ch8, TEN on ch11, and ABC on
ch12 in most capital cities.

MrT.



Re: can digital get picture if analog TV is weak?



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...... drop-outs. :-)

MrT.



Re: can digital get picture if analog TV is weak?


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A log periodic has lower gain than an equivalent sized Yagi. There is
nothing that would make a log periodic better. Having excessive
bandwidth is pointless. The only improvement I could see would be to
have a loop antenna, maybe like a cubicle quad, for lower noise and
slightly higher gain than a Yagi.

Dorfus

Re: can digital get picture if analog TV is weak?




wrote:
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Just perhaps  you  could  provide a  link to your   "digital" antenna,  then
we  can  all  evaluate it.
                                                       bassett



Re: can digital get picture if analog TV is weak?



"bassett"
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** Dave did that -  about 2 weeks ago on " aus.electronics ".


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

Dave. "




.......   Phil




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