I am aware that Freeview is being pushed so that we can all go digital ASAP but if Freeview can use an ordinary aerial with standard coax then does this mean that the quality is less than satellite signal or are they both the same when they come out of the set top box.
Are there any differences and should we be looking at a higher coax quality for Freeview
Just wondering
Mike
Depends on the signal strength. You might get away with the old style coax in a very strong signal area, but there is no graceful degradation. Any noise and you can lose the whole signal as it dips below the threshold on digital.
A new antenna and downlead is meant to make quite a difference.
I presume antennas do not degrade with time then so do you mean it is a different spec for Freeview?
Also do you mean the downlead should be of satellite quality?
Thanks
Mike
Satellite needs different cable because it's transmitted at much higher frequencies. This makes no intrinsic difference to the end result.
Bad assumption. They do, or at least the connections do, unless the installer is very particular about sealing the cap and cable entry. Most cheapo "contract" aerials will have water in the connection box after the first shower of rain.
Depends where you are. In some places the Freeview Multiplexes are not with in the same aerial group as the analogue transmissions, fitting an aerial the properly covers the required frequencies will help.
CT100 has considerably less loss than bog standard "TV Coax". The less signal you lose the better...
Yes the downlinks are roughly 10.7 to 12.75GHz but the LNB on the wok down converts that to 950MHz to 2.1GHz (ish). 950MHz is above above Band IV/V so "TV Coax" wouldn't be particularly suitable. However the satellite Tx frequency does not go down the cable from wok to box.
"Mike Saunders" wrote in news:4139e808_4@127.0.0.1:
IMO freeview is not all it's cracked up to be. I get excellent picture and sound quality, but there are annoying occasional very short sound losses.
This may be due to sporadic electrical interference from elsewher in the hovel, but they don't warn you about it, and many boxes appear not to be protected, and the system is clearly more vulnerable.
Also there are occasional pixilation artifacts on very busy pictures due to bandwidth restrictions.
It is a way to get a picture across using less bandwidth, but having given the broadcasters a bandwidth knob with digital techniques, they're happily screwing it down all through the chain. (Look at the picture quality on BBC
24 hr news - 3 shades of pink, and textures otherwise achieved only by cheapo camcorders).You need a good aerial, and good downlead to minimise electrical interference, because digital does not degrade politely like analogue, but totally collapses.
I'd stay away from it if you have decent analogue; it may improve after the switchoff, but not before
You could post in uk.tech.digital-tv for mor info; I doubt if it will help but Bill the aerial man has a fund of good stories.
mike
Yes...maybe. I'm not a major expert on this (years since I studied antennas) but one factor is that the antenna should incorporate a balun to match the essentially balanced antenna to the unbalanced feeder. Older antennas don't have this, but it's more important for digital, to reduce noise picked up by the feeder. In addition, the channels used by digital may not be in the same range as the ones your original antenna was meant for. A wideband antenna seems to be the thing.
It needs to be properly screened (foil screen, not the 'low loss' wide mesh stuff. I think this subject was rehearsed here recently.
There is some good stuff (and details of channels used by each mux, in your area) at:
There are also documents that explain the antenna requirements in more detail.
Assuming that you are getting adequate signal from both dish and aerial then the main factor that will determine the picture quality is the bitrate used to encode the channel.
Alas bit rates are often selected for commercial reasons (i.e. low bitrate = more channels in a given bandwidth = more cost effective) rather than aesthetic ones.
Freeview tends to give quite good picture quality on some channels - but less so on the ITV muxes. It is less good on fast moving scenes (i.e. football for example) where the bandwidth restrictions become more noticeable.
Something like CT100 cable will tend to give better results not only because it is lower loss (hence more signal at the receiver), but also it is less susceptable to picking up Interference (impulse noise in particular) than traditional "low loss" co-ax.
The other thing to consider is that aerials do "age", in particular co-ax absorbs water which will attenuate the signal. This is particularly noticeable if your local region has channels allocated toward the top of the spectrum where the absorption effect of the water will be more noticeable.
Aerials can also degrade, due to mechanical damage accumulated over time (birds, wind etc), and also corrosion. The larger higher gain aerials tend to suffer more. Seven years is considered a good lifespan for a high channel, high gain aerial.
If you look out the technical standards i believe that Sky via satellite has a higher bit rate than terrestrial freeview, as the available radio bandwidth is less limited, so it should be a better picture. Also digital radio from satellite has a higher bit rate than terrestrial DAB so the quality is better.
luggsie
some boxes handle this better than others have noticed. The oldish pace DTVA fro example tends to introduce lots of clicks and squeaks when it gets glitches in the signal. Something like the Netgem however handles it much better.
The QAM64 modulation scheme used on the ITV muxes is more vulnerable to this than the QAM16 used on the other muxes.
To be fair, it does not degrade at all right up until you reach the threshold of the capabilities of the forward error correction used. At that point it begins to suffer drastically. Subjectively that can be more annoying if you only have a poorish signal, since the transition between a perfect picture, and pixels, clicks, and frozen images is more noticeable than a general covering of "snow" over what you are trying to watch.
There are also some reception problems that digital is far better at dealing with like multi path, (i.e. ghosting).
Indeed, it ought to improve when more spectrum is made available. You also need to factor whether any of the channels not available on analogue are of value to you.
Yup that is true, well worth a visit for that if nothing else. (do a google groups search on "riggers diary").
Note that radio on freeview and DAB are unrealted technologies. Digital radio on freeview tends to sound much better than DAB (which is to be honest, crap!)
John Rumm wrote in news:413a43b5$0$80696$ snipped-for-privacy@ptn-nntp-reader04.plus.net:
Har har.
mike
Why was that funny?
They do degrade over time, mainly due to effects of weathering.
All cables lose a bit of signal per metre. Higher quality cables have less signal loss per metre than low quality cables. "Satellite quality" cable tends to be higher quality.
So it all depends on how strong the signal is to begin with. All satellite signals are fairly weak, which is why higher quality cable should always be used with satellite. For terrestrial, it depends how close you are to the transmitter, etc.
At my location I HAVE to use "satellite quality" cable (CT100) for freeview or I can't get a reliable picture.
Not down the cable it isn't.
The LNB on the dish downconverts the Gigahertz-range signal which comes from the satellite into something very close to normal TV frequencies.
Also, analogue doesn't support widescreen. If you have a widescreen television, or want to watch widescreen programmes on a 4:3 TV with black bars top and bottom, then you'll need some sort of digital TV reception.
Christian.
.. and thicker cable, or the pictures won't fit through it anyway.
When I was three or four, I asked my dad what the things with spikes were for on people's roofs.
He told me, quite reasonably, that they were to pick up television pictures - we had just got a set.
In those days, the old Band 1 H-shaped antennas were very commonplace, so I naturally assumed that somehow the pictures were slotted into the top, were perhaps rolled up to go down the cable and then appeared on the screen - as if by magic. There was even a short film that was shown about how television worked which showed something like this for the transmission part so it never occured to me to think differently.
However, by the time I was about 8 or 9, this had all changed. I can remember going to the public library and pulling out a book on how to build a radio set. I took it to the counter and gave it to the lady with my children's ticket (which was not meant to be for books "for grown ups"). The librarian looked down her nose at me and suggested that I would be better off with Janet and John or Noddy. I explained to her that I could read the book perfectly OK. She asked me to do so, which I did. Then thinking that she could catch me out, asked me to explain how a radio worked. I closed the book and explained how a superhet operated. She stamped the book and asked me if I wanted any others like it.
.andy
To email, substitute .nospam with .gl
The boxes are now so cheap that I bought one just to try. There are two TVs on the aerial and I found that a £5 amplifier from Asda (to feed the digibox which is on the end of a few metres of cheap coax) was the only upgrade that was required. The picture and sound quality is never less than excellent and invariably better than the analogue signal (whether compared against the amplified or unamplified signal).
MBQ
Hmm. On a *good* TV with a decent aerial, with the sound fed to an external system, I'd defy anyone to reliably tell the difference between analogue, NICAM, or Freeview - provided that source is mono.
Picture wise, pretty well the same applies (apart from aspect ratio) apart from on the odd occasion the broadcasters are providing a superior source than normal.
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