can digital get picture if analog TV is weak?

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:

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.

It's my experience that most digital receivers give a small amount of pixel break-up infrequently with a strong signal, and a large amount of frequent break-up, or no picture at all with a very weak signal. The performance of digital tuners varies just as much as analog tuners, however frequent digital drop-outs can be even more annoying than a poor analog signal IMO.

I suggest you simply try a STB that can be returned if unusable in your location.

MrT.

On Thu, 02 Aug 2007 23:36:52 -0700, snipped-for-privacy@ml1.net wrote in aus.tv.digital, [aus.electronics]:

I have very variable analogue reception here in a unit in Hamilton, Brisbane. At some time, each channel is hardly watchable, especially ch.7; at other times, they are all bearable.

However, the digital reception is pretty close to perfect. There are occasional pixelations, picture break-ups and annoying loud audio artifacts, but they may well be the result of the tuner.

To answer the question: get a STB and try it - you've got nothing to lose.

--
Michael Bednarek   http://mbednarek.com/   "POST NO BILLS"

The only sure way to know is to borrow a stb and try - remember you don't need any reception below ch6 (analog) for digital channels and that gets rid of a lot of noise. A friend who lives in the direct shadow of a shopping centre in the inner west of Sydney has absolutely no analog reception but when he installed a Fracarro digital antenna he was able to pick up all Sydney digital stations by pointing the antenna at a building nearly 90 degrees off the correct normal direction - his only panic is if they ever redevelop that 5 story block of units! So it's worth getting an Antenna specialist out to do some in situ measurements...

*** that's because 7 & 9 are UHF

probably because the channel 10

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

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

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

messagenews: snipped-for-privacy@d30g2000prg.googlegroups.com...

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.

messagenews: snipped-for-privacy@d30g2000prg.googlegroups.com...

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.

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 f*ck-wit, to answer.

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

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

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

messagenews: snipped-for-privacy@d30g2000prg.googlegroups.com...

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

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.

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

"bassett"

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

" Also, my "digital" antenna is a log-periodic type, like this one:

Dave. "

....... Phil

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.

It's all about syntax - of course there is no such thing as a digital antenna or a digital microphone for that matter but it is human nature, especially in Australia to shorthand the language even if it's technically wrong. Personally I like this charming Australian characteristic.

A so called "digital antenna" is one that has been designed to receive those frequencies that are used in Australia for DTV.ie nothing below Ch6 (analog). Mine is a Fraccaro log periodic

as is my friend who has absolutely no analog reception regardless of antenna design array, well not unless he was willing to put up a 200 foot pole! The Fracarro pulls in 96% signal strength with similar quality on his Topfield 5000. And here I am a few suburbs away with perfect line of site with 100%. So this antenna must be doing something the others don't, all tried by a antenna specialist engineer (not Hills! etc) who did extensive measurements of signal strength and quality using a range of antenna designs. So as far as my friend is concerned he is not the least bit interested in the technical analysis just the excellent results he has achieved for a $50 antenna that is quite tiny, even the birds don't sit on it and another $150 for installation and new quad cable etc..

Because you are using a triplexer, you may need a CATV type amplifier for the antenna. It is possible that you will need an amplifier for each band, and use the proper traps for them. This is something that will require the services of a professional installer. He would start by evaluating the antenna with a spectrum analyser to make sure that it is in spec, and then work his way back to determine the exact needs.

As far as a digital TV with a digital tuner is concerned, it will only get digital programs as long as they are being transmitted in digital. This means that in your case the stations being received would have to have their program content on their signal carrier in digital, and not in analog.

When a consumer digital TV is receiving an analog signal, it will work just like an analog TV is concerned. This means that if the signal is noisy, the set will reproduce the noise just the same way as any other analog TV. In fact, a high end TV will usually be more sensitive to the noise, and the viewer would probably see the noise a lot better!

If a digital TV is receiving a digital signal, and the reception is weak, as long as the signal data is above the capture threshold of the TV's receiving and processing system, the picture should look very good. If the signal goes below the capture threshold, the viewer would normaly see pixelations in the picture content. The audio would probably be also dropping out and in with the signal variations.

The amount of signal required for a digital TV to have stable reception depends on the capture threshold. Some digital TV models can work down to

10% to 15% signal in relation to a normal level. This means that the set may work up to about 85% noise content in the signal.

This subject is very hypothetical. The above is only an example. There are many factors and variables involved. The proper answer is to get a professional antenna installer in, and let him check it out and make the proper suggestions. At the same time he can also check out the TV set. I have seen people complain about an antenna or cable installation, and it turned out the fault was in the tuner or IF section of the TV.

--

JANA
_____


 wrote in message 
news:1186123012.494870.141410@o61g2000hsh.googlegroups.com...
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?