Freeview reception has changed?
From time to time people find that their Freeview box, integrated set (idTV) or Personal Video Recorder (PVR) has lost many channels without any apparent changes.
There are a number of factors to consider
Freeview is broadcast on digital multiplexes. This means that, once broken down into a stream of bits, each television channel is combined into a single transmission of 1s and 0s. This means that reception is of the multiplex first if this is lost it affects all the channels in the multiplex in the same way.The signal strength received by the box or TV for a particular multiplex from a given transmitter determines if the data can be received or not. So, a poor signal results in no data, an adequate signal in perfect data and a low signal in either none or all.
Poor digital signal levels do not result, as they do with old-fashioned analogue television, in a sub-standard picture or sound. Poor signals often result in a perfect data-stream, but are prone to periods of no reception. Sometimes this will be for hours, but can also be several times a minute when caused by induction from fridges, freezers, central heating systems, two-stroke scooters, baby monitors and so on.
If you have lost ALL your Freeview channels
First disconnect the aerial lead from the Freeview box or TV set and reconnect it and then follow this reset procedure to scan for channels again. If this does not result in services being restored, check the Freeview transmitters page to see if there are any engineering problems with your local transmitter.How to check all cables, connectors and aerials
The RF connectors need to be in very good condition to work. There are two general types:Factory-fitted connectors are very reliable as they cannot easily be taken apart, but they can be damaged by wear and tear. On the female-type the central section is often composed of two parts which can often be forced apart, resulting in a poor connection you can push them back together if this has happened with a pair of tweezers. On male connectors if the central pin is damaged, you will need a new cable. If there are any loose partials in the connector, remove them.
Another problem with these cables is that quite easy to sprain the connector at the back which causes little obvious external damage, but disconnects the internal connection. This happens often when a set-top box is pushed backwards into a cabinet.
Hand made cables can also suffer from similar problems to factory made ones and they are also prone to accidental damage from a cable being pulled. If such a connector is not firmly attached to the cable, the connector may need refitting.
Cables
Make a visual check of the cables. There are a few basic checks:If the cable has been slashed or cut, it will not be very effective or reliable. If such a cable is fitted externally, this can allow rainwater to enter the cable and this will reduce the signal levels.
You can easily damage an RF cable by crushing it, for example in a door. If the outside of the cable has a permanent kink in the cable or has been very tightly looped, this could be the site of damage.
Aerial
For reliable and effective Freeview reception, a rooftop aerial is required. It is hard to make a visual check of such an aerial without putting yourself in potential danger.You can make a visual check of the route between the aerial and the transmitter. Any form of obstruction will damage the digital signals. In particular trees coming into leaf, as these will leech the signal before it reaches your aerial. This applies to both trees adjacent to the aerial and at a distance.
Another common problem in cities is building work. A large crane will often change position many times during the day, and if this is between your aerial and the transmitter this can reduce the signal levels in an unpredictable way.
If your system uses a booster, the power may have failed. Check the fuse to the power to the booster.
Weather problems
There are two main weather problems that effect Freeview reception.The Inversion Effect: please see What is the Inversion Effect and why does it effect my Freeview TV reception?
Wind: high winds sometime can dislodge the aerial this results in a poor signal.
Rain: poor or old cables can fill with water and this results in a poor signal. If this happens, the cables will require replacement.
Help with Freeview, aerials?
Friday, 29 April 2011
D
Donald8:04 PM
Hexham
In the last few weeks - with no apparent changes in our setup which is a Thomson Scenium TV and a Humax Duovision PVR 9200T - the reception on the Group 2 multiplex channels has declined with these channels showing momentary freezes which make the programmes unwatchable. We've had no problems at all previously with the quality or functionality of the Humax - although the picture on the TV screen at the left edge isn't always perfect. Any suggestions as to why the freezes might be occurring would be very welcome.
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Donald's: mapD's Freeview map terrainD's terrain plot wavesD's frequency data D's Freeview Detailed Coverage
Monday, 2 May 2011
D
Derek Donovab8:43 PM
Hi
I have a Topfield TF5800 Free view box, a few days ago I was told (Via a notice on my television screen) to retune which I did as the Wenvoe Transmitter was changing. Now I'm getting two programmes on each channel with most of them mixed up i.e. Yesterday which should be on channel 12 is on Film on channel 15 etc.
I haven't changed anything so it must be something to do with the retune.
I've done everything, a factory reset; I've formatted the hard drive and reinstalled MyStuff (The Topfield Program) quite a few times but it's still the same.
Any ideas of what more I can do?
Regards,
Derek
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Rich9:48 PM
Hi,
I am unable to receive channels on the multiplexer A .
my postcode is SY5 (wrekin transmitter).
Should I be able to get these channels ok?
I'm using a humax freeview PVR. Tried your reset procedure and no luck yet. Any ideas?
thanks
Rich
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Wednesday, 4 May 2011
Hi i have a brand new (less than 6 weeks old) Samsung tv with built in freeview
We had full channel access til 13th April and now we are missing Multiplexes 2 and A.
We live in Nottingham city centre, in an apartment block. NG1 1AS
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Andy's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
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Martin4:34 PM
Reading
I live in RG7 3ED and have been using Panasonic TX-L37D25B for 4 months picking up all digital and associated HD channels 51, 52, 54.
I have been away for three weeks and on return the TV requests retune for new channels and now I have lost all HD channels and many other digital ones are very poor reception. I have reset the TVs and tried auto setup but no joy.
Any ideas why the quality of the digital channels is reduced and all HD ones have disappeared please?
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Martin's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
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Mike Dimmick6:55 PM
Martin: Since you're getting HD channels I assume your aerial is pointing east to the Crystal Palace transmitter. If it's pointing south-west to the Hannington transmitter, you would only be getting fringe reception of Crystal Palace (Hannington does not transmit HD signals until after switchover).
A number of other transmitters have switched over or been reconfigured since you've been away, which will have changed the amount of interference slightly, but it's not expected to have caused major problems.
Have you checked all the things at the top of the page?
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Mike Dimmick6:58 PM
Andy Moss: You may be using the Waltham transmitter. On the 30th of March, Mux A moved to a different frequency, and on the 13th of April, Mux 2 also moved. You will need to do a factory reset of the TV, so it forgets where the channels used to be, and rescan it. The Factory Reset option may also be called 'Default Setting', 'Full Retune' or 'First-Time Installation'. New equipment should come with a leaflet telling you how to do this on the switchover dates. Follow that process. The information should also be available at Samsung's website or at TV Re-tune ____If you're still having problems, please post on the Waltham transmitter page.
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Thursday, 5 May 2011
N
nat10:02 AM
Cheltenham
Morning,
I went to bed last night with freeview working fine and woke up with all my channels saying no signali then tried to reinstall channels and it said no channels found.
Iv had it just under a year and its signal has always been fine.
Any advice? Postocde is gl50 4bl cheltenham?
Thanks
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nat's: ...
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David4:54 PM
Yateley
For the past 3 days Channel 43 has been very poor. Analogue and all other freeview channels are fine. I have 4 TVs. I retuned 2 of them and neither will even find channel 43. The 2 I did not retune still have channel 43 but with poor reception. Freeview has generally worked well for some years now. I am on Hannington. This is the longest period I have experienced of such poor reception (no reception) on this channel. My postcode is GU46 6ES. Other friends nearby are having the same issues.Could help please ? Many thanks.
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David's: mapD's Freeview map terrainD's terrain plot wavesD's frequency data D's Freeview Detailed Coverage
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Mike Dimmick6:21 PM
David: By channel 43, I assume you mean Multiplex 2 rather than Gems TV!
The problem here is that Hannington's digital signals are broadcast at seriously reduced signal levels to the east, to protect Guildford's coverage area. Channel 43 is also used by Guildford for analogue ITV1, at quite high power.
For this reason, Digital UK predicts no coverage for you from Hannington. The predictor is often pessimistic - aerials often reject more signal from behind and from the other polarization than the model used for the predictor - but a zero prediction means there will be frequent problems. The prediction is a probability of finding a location for the aerial that gives a probability of reliable results, so you can get a frequently-failing service where the predictor says zero.
The restriction will be removed at switchover, when the digital transmissions move to the main antenna at the top of the mast (which currently provides the analogue services).
It's likely that other changes at other transmitters have caused a change in the amount of interference you're getting, though I can't pin-point a specific change.
If you can't wait until next February, you will have to get an aerial pointed at Crystal Palace, but the post-switchover service from Hannington is expected to be easier to obtain. Alternatively, look into Freesat.
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