My ITV/C4 Freeview channels have disappeared - what can I do? Is it my SCART ca
Brian Butterworth published on UK Free TV It is a feature of television signals that they can be effected by the weather. Aside from the obvious damaged that can be caused by wind or torrential rain, the onset of summer can cause a more intriguing problem called "inversion".
Basically, when the sun heats up the land, the hot air can get trapped below cold air at high level. This creates an "inversion layer" which acts like a polished mirror to TV signals. This causes two problems: you can receive both the original and a reflected signal from your own transmitter (on analogue TV this appears as "ghosting") or interference from TV transmitters that are normally too far distant.
The ITV/C4 multiplex of channels (ITV-1, ITV-2, ITV-3, ITV-4, CITV, C4, More4, E4, Quizcall) use a transmission "mode" called 64QAM, and it is sadly much more prone to these problems.
So, whilst a loft-mounted aerial will provide reception at some time, it will fail at others. The only real solution is to mount the aerial (or a new Class I aerial) outside on a pole, but some people report that changing the cable from the aerial to the set-top box to the high-grade satellite cable can also help.
The SCART connection, by the way, only carries a single TV picture, not the Freeview transmission multiplexes, so if this is disconnected it will result in degradation to every channel at once.
All questions
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Sunday, 7 September 2014
J
jb3811:39 PM
Paul Radford : A post code would have been of assistance with queries of this nature, however, if you have reset your TV three times and yet the situation has remained the same, then provided that your TV automatically detects a DVB-T2 signal and that you do "not" have to enter it (DVB-T2) beforehand, then the source of the difficulty you are experiencing "might" actually be caused by a PID data error in the transmitters EPG and "not" anything connected with your equipment, this having already occurred in the area served by the Emley Moor (West Yorkshire) transmitter.
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Dene11:41 PM
What a mess this latest update has turned out to be! Updated on Thursday and now I can't access a lot of channels using the number buttons on the remote. When I press 1 for BBC1 the screen is black as is BBC2 and stays black...what is going on?
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Monday, 8 September 2014
E
Ellen 8:32 PM
I have lost all channels but BBC channels on my Freeview TV in my bedroom after the retune. I use a indoor aerial and it was perfect before. Where have they all gone and how can I rectify this? I live in Nottingham.
Thanks
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Anthony10:35 PM
Accrington
Ellen : Unless you are within good line of sight of a TV transmitter, an indoor aerial can be hopeless at picking up digital TV services (unless you buy one that has a built in booster powered by the TV aerial socket), and it also can pick up interference from electrical switches and appliances causing break up pops squeaks and pixellation etc and also go bad when people move within the room. Try retuning and if you still have no luck, the only solution is a properly installed roof or loft aerial with a masthead amplifier to boost the signals into your Freeview TV.
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Anthony's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
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Paul Radford10:44 PM
London
JB38 - My post code is SW18 4BB, I have now tried tuning my TV again and now all my freeview HD channels have now disappeared. Is there no straight forward answer to why this has happened?
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Paul's: mapP's Freeview map terrainP's terrain plot wavesP's frequency data P's Freeview Detailed Coverage
Tuesday, 9 September 2014
J
jb3812:28 AM
Paul Radford: Unfortunately, when dealing with digital reception problems its very seldom that a straightforward answer ever applies. But though, as you are located at only 5 miles away from the Crystal Palace transmitter, then the immediate thing that springs into mind is the possibility that the signal strength being received is excessively high to the extent that its causing instability in the tuner, HD channels always first to be affected in situations such as this even although SD might well be operating as normal.
Purely for test purposes, if you are using any type of powered distribution amplifier then try bypassing it, as these devices always add an element of boosting to the signal, that said, I do realise that prior to the recent retune you were receiving the HD channels OK, me only having mentioned the problem with Emley Moor as your location was unknown.
However, as you have already carried out a reset on the TV rather than just an auto-tune, you have in effect done the maximum that a viewer can do, although the only aspect I was wondering about is whether or not your TV automatically detects a DVB-T2 transmission? or if you have to select this mode, some do.
Should it transpire that you have to, go into the tuning menu / manual tune and select DVB-T2 then enter and scan Mux Ch30 and see if this picks the HD channels up, if by any chance it does, then carry out the same procedure again but this time enter Mux Ch33 (COM7).
As a matter of fact, irrespective of whether or not you can receive the main HD channels try a test on Mux Ch33, as this transmitter only radiates on 43Kw compared to 200Kw on the main HD mux, giving an update on the results.
(Knowing the model of TV involved would also be of assistance?
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Isla5:28 PM
Hi there, are other people still having problems? I still have the BBC channels freezing. I have checked and the transmitter is Highlands and Islands, but we're in Aberdeen - I think our transmitter should be Durris. Any ideas how to hook up to the correct transmitter?
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MikeP
9:17 PM
9:17 PM
Anthony and Ellen
Depending on where in Nottingham Ellen lives it is rare to need a booster. In the experience of many respondents to this website, boosters are often the cause of problems rather than a cure.
Unlike the old analogue services, digital is very sensitive to signal strength. If there is too little then the will be break up of the picture (pixilation) and sound and sometimes total loss of channels, sometimes just some of them and sometimes all of them. If there is too much signal strength the tuner can be swamped (overloaded) by the excessive signal and give much the same problems as with too little signla. That is particularly true for HD equipment with the DVB-T2 type tuners.
So I would strongly advise using just a good, well installed aerial of the log-periodic type (for receptions some years into the future) without a booster/amplifier initially. A check on screen of the signals strength will show whether it is too weak or too strong. Ideally it should be between 60% and 80% but not more and not less. Only if the signal strnegth is significantly less than 605 should you even consider whether a booster/amplifier would help. Remember that they booster the noise and interference as well as the wanted signals, so be wise and avoid if at all possible.
Ellen: could you enter your post code into this site (or that of a nearby shop) so we can work out whether you are using Waltham of Nottingham (Kimberley) thransmitter and whether there are any significant hills (such as at Mapperley Top, Castle Hill, etc) between you and the transmitter. I know the area quite well from when I worked throught Nottinghamshire and Leicestershire.
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MikeB11:13 PM
Isla: Mine seems to be OK today...., but the problem isn't consistant, as you know. I've just emailed the BBC to ask if there is any change in the data stream that would cause a problem with the boxes software.
Stuart on the reception thread has pointed out that some older TV's and Labgear digibox's have also had a problem, and I'm wondering if they are all programmed with the same software.
If you put your postcode into this website (or just when you just post a question), there will be links, including the one to DigitalUK's website. Durris is on RF channel 28, but it might be that the other transmitter has been picked up first (with a lower frequency) - its one the less great things about the Goodmans box that it doesn't manually tune, and so it does sometimes do this.
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Wednesday, 10 September 2014
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Isla8:02 AM
@Mike B I've tested the postcode and the transmitter is definitely Durris. This is an old TV - not even flat screen . The plan is to buy a new box at the weekend, is this likely to help? Any recs on what to get? I really don't want to spend too much as hadn't planned to spend anything!
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