PDA

View Full Version : Freeview Signal Quality



sahilcc7
05-09-2011, 08:39 PM
We currently have freeview setup on 2 TV's. The picture was noticeably better before we moved houses. At our old we had our UHF connected directly to the freeview box.

At our current house, we have our aerial connected into the roof into a splitter which then sends the signal different ways (3 rooms have TV jacks). To improve the quality of our TV's in both rooms, could I disconnect one signal to the room we don't need? Any other ways to improve signal quality on the TV's?

And I have never actually been up in the roof (Only a friend has) so will there be 2 different spitters for Sky and UHF? And what exactly do I need to unplug?


TIA

CYaBro
05-09-2011, 08:43 PM
Being a digital signal you won't get better or worse reception.
What will happen is it will either work or it won't.
Or you may get the picture freezing, pixelating and breaking up if you don't have enough signal but it's not like the old analogue signal which would get ghosting and snow etc.

Are you sure you have got Freeview|HD and not the analogue channels?
You can get the EPG?

sahilcc7
05-09-2011, 08:49 PM
In one room the quality is good and quite poor in the other one. The room we don't use has better quality, so if I disconnected the not needed one and plugged in the one we need improving, would that improve quality? I've seen it done before at this same house when we first moved in, but the Sky person stuffed it up. (And also left messy wires hanging out, so hope to get rid of them also.)

And also, the person who came over and set up the jacks for better quality, said there was an amplifier up there.

feersumendjinn
05-09-2011, 08:50 PM
I have heard that the more you split an un-amplified RF (VHF/UHF) signal from a single aerial, the weaker it gets, so you probably need an amplified splitter (or less aerial connections (to TV's etc), or more aerials ;)).

Aerial distribution amplifier This allows you to divert your TV aerial signal to several rooms. You connect the aerial lead to the input socket and then run extension leads from the output. Because the signal is amplified it can be split without becoming weaker. If you want to split it just two ways, and have a strong signal from your rooftop aerial, you may not need to go to the expense of one of these.

From here
http://freeviewnz.tv/setup_support/questions_answers/category/glossary

CYaBro
05-09-2011, 08:54 PM
What do you mean by poor quality?
As I said in my first post, if you are correctly tuned in to Freeview|HD (or Satellite for that matter), the picture will either be perfect or it won't be there at all.
Changing cables or unplugging things isn't going to make a difference to picture quality.
If you weren't getting any picture at all then it's a different story.

Edit: I just had a thought, do you have a freeview box at both TVs and you can watch different channels at the same time?
Or do you only have one freeview box which feeds it's RF output signal to the other TV and you can only watch the same channel on both?

Edit: What feersumendjinn is true in a way but let me say again, if you are sure you are tuned in to Freeview|HD, you will NOT get better or worse picture quality. If the signal from the UHF antenna was being split too many times and was too weak at the TV then you will get no picture at all. If you however are tuning in the analogue channels (ie NOT Freeview) then your picture would look like crap.

sahilcc7
05-09-2011, 08:57 PM
Hmm, okay must be just the aerial we have now, or different house. Would excess cable decrease quality? I've read on other forums that by removing the splitter and going straight from aerial to HD box, improved the signal (Possibly for analogue).

feersumendjinn
05-09-2011, 09:08 PM
I think you'll find the RF signal is still transmitted as a analogue signal (frequency or amplitude modulated) but encoded digitally (on=1, off=0), which is why you need a decoder/STB.

Changing cables or unplugging things isn't going to make a difference to picture quality.
In fact it will, the weaker the signal the more corrupted is the decoding (more bits missing/dropped), resulting in blocky interference and/or stuttering.

CYaBro
05-09-2011, 09:12 PM
Yes excess cable could decrease picture quality on analogue signals.
On a digital signal the picture would be perfect or it would not be there at all - there is no middle ground of bad picture quality on a digital signal.
The same goes for a splitter, the Freeview|HD picture will either be perfect or there will be no picture at all.

I did a Freeview|HD install a couple of weeks ago and found that the TV was not getting any digital signal so no picture at all.
Climbed into the ceiling and found an old splitter that was not needed so removed it.
Tried TV again = perfect picture.

CYaBro
05-09-2011, 09:19 PM
I think you'll find the RF signal is still transmitted as a analogue signal (frequency or amplitude modulated) but encoded digitally (on=1, off=0), which is why you need a decoder/STB.

Doesn't really matter how it is transmitted (I don't know the technical aspect of that) but what I am saying is true.
With the digital Freeview|HD signal you will have either a perfect picture or no picture at all - there will be no poor/bad picture quality.
There could be other factors that are making the picture look bad like the cable going from your STB to the TV. As this is now an analogue signal this cable could be causing problems.
If you have the STB connected by HDMI this won't cause picture quality problems though.

sahilcc7 can you confirm that you are in fact watching Freeview|HD? Can you view the electronic program guide?
Does each TV have it's own freeview box? How are they connected to the TVs?

CYaBro
05-09-2011, 09:28 PM
I think you'll find the RF signal is still transmitted as a analogue signal (frequency or amplitude modulated) but encoded digitally (on=1, off=0), which is why you need a decoder/STB.

In fact it will, the weaker the signal the more corrupted is the decoding (more bits missing/dropped), resulting in blocky interference and/or stuttering.

That's what I said in my first post.
That's not really bad/poor picture quality unlike an analogue signal that gets snow or ghosting.
It's similar to what happens with Sky if you get rain fade, sometimes the picture is still showing but it freezes and breaks up and isn't watchable at all.

sahilcc7
05-09-2011, 09:52 PM
Yes, TV #1 is connected to a DSE Freeview HD box with EPG and TV #2 /Projector with Play TV (Not as good quality).

The connection on TV #1 at the wall is not connected properly (Sky guy again :( ). When you move the connector a bit, the signal will go and TV will display 'Check Cable' or Similar. It's just not connected properly. Could that be the cause? And on TV#2 the wall socket is connected by 2 cables from the roof to one jack.

Can post pictures if needed.

feersumendjinn
05-09-2011, 10:03 PM
The reason why you dont get ghosting is because the encoded signal is decoded using error-correction (removing extraneous information (multipath signals/ghosting)).
When the signal is weak the parts of the code necessary for reference to correct frames would be missing (blocky=digital = snow=analogue).

feersumendjinn
05-09-2011, 10:32 PM
http://dicksmith.co.nz/product/L4219/kingray-2-way-amplified-tv-splitter
Sahilcc7, Try this if you want to improve your signal strength, bigger ones are available, (might pay to check your aerial/wiring too if its a few years old), get a competent aerial installer (not a "sky guy").

feersumendjinn
05-09-2011, 11:15 PM
http://pressf1.co.nz/showthread.php?91093-UHF-signal-booster-and-Freeview

dugimodo
05-09-2011, 11:43 PM
Sounds to me that you need the connections looked at, the signal leaving a splitter is the same strength on all output ports and should only be weaker if there is a longer cable run or a bad connection, disconnecting outputs doesn't affect the signal strength on the remaining ports, in fact in some designs they work better if all ports are terminated. The amplifier should have enough output strength to split several times usually.
Assuming there are wall plates you could take them off and check the connections yourself. The common connector in use in NZ is not a great one, and cheap ones use crappy screw terminals that dont always make good contact. The central wire needs to make good contact as does the braid or foil screen and they must not be in contact with each other. A short circuit on any port will affect the signal on all.

CYaBro
06-09-2011, 12:24 AM
http://pressf1.co.nz/showthread.php?91093-UHF-signal-booster-and-Freeview

Yup that thread confirms what I am saying.
The amp improved the picture quality on the Prime analogue signal.
It also improved the freeview hd signal as they were getting dropped frames, which is not a picture quality issue.

sahilcc7
06-09-2011, 05:30 PM
Must be the longer cable then. And is the Maori channel HD? To watch RWC games on. That might be fuzzy because I think its still analogue.

Speedy Gonzales
06-09-2011, 05:33 PM
I think the only channel that's 1080p is 3.One and 2 are 720p. The rest are 576

PPp
06-09-2011, 06:01 PM
I've just installed a 91 element aerial to improve our signal strength for tv and PVR. We're using digital freeview. Freeview on the tv was good but the PVR was pretty marginal pixelating at times(mainly recording times!!) The difference to the tv is quite noticeable in HD(I would say perfect) and the pvr has become quite acceptable. We are in a marginal area for signal strength. Unless you are in a high strength signal area with a good aerial I would try running your setup on one tv and see what you get. If its good you know everything works(so far) Just add the other tvs one at a time and see if they are acceptable. A lot of cables are not put together properly, the end connectors need to have the central wire soldered into the pin to have a pretty permanent solid connection, If your signal is not strong, using an amplifier on three tvs would be pretty marginal I would say.

sahilcc7
06-09-2011, 07:22 PM
Checked out the Play TV today and it TV 1,2,3 were great. HD picture. The others were freezing at times but watchable. That was the problem - just the analogue channels. Don't really care about it, RWC will be on the HD channels.

Thanks guys.