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?
Thursday, 22 September 2011
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James Collins11:06 AM
Kingswinford
Good morning.. since Tuesday, 20th Sept. have lost few Freeview channels, inc. "Film 4" and "Yesterday", firm favourites!! have wroeked perfectly on Wrekin Transmitter until then!. We had Digital.co.uk come and check everything before April of this year when Wrekin started its changeover, then msge came up to re-tune on tv last week before 28th Sept. which we did. now we in this mess.What has happened.
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James's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
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david thompson11:16 AM
Hull
i have lost channels in band C ie; dave picktv
how do i get them back
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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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Mark11:52 AM
Hi we have no channel at all since midnight tuesday. We have a professionally mounted aerial pointing to the Malvern transmitter. I have tried two freeview boxes, all cables are fine & well connected and the aerial looks normal. What is it?
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Dave Kendrick1:20 PM
Can anyone help?We have lost all BBC Channels yesterday on our terestial free view,Having gone to the usual help sites we seem to be going round in circles,answering the same old questions time and time again retune etc. The signal strenght is 100% on all channels But the quality is 0% for BBC Channls and 80%-ITV channels This surely is a transmitter problem and who or what can we possibly do.
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david thompson: Please see Single frequency interference | ukfree.tv - independent free digital TV advice .
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Mark: I would have a look at the Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice page. I can't say more without a full postcode.
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Friday, 23 September 2011
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Tim2:06 PM
St. Austell
We have a loft mounted aerial looking at Caradon Hill transmitter from PL25 3QR and run a six way distribution amp to four TVs. We had been happily receiving all channels until a few weeks ago and now we only get the 10 channels on D3+4 multiplex, C25+. Retune on all TVs makes no difference and I've tried changing out the distribution amp with a spare, which also has no effect. Any ideas?
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Tim's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
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jb382:50 PM
Tim: I would be inclined to either carry out a factory reset, or alternatively blank out the EPG stored by scanning without the aerial being connected, then after re-connecting same make a further re-scan.
The point is though that "if" you are receiving SDN/D3&4 then there isnt really a fault as far as actual reception is concerned.
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Tim3:16 PM
St. Austell
Thanks jb38 that's exactly what I was thinking however exactly the same thing is happening with all four TVs attached, which I can't quite explain...
We have three different Samsung TVs with inbuilt tuners and a BT vision box.
Reception for the ten channels on D3+4 is absolutely fine.
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Tim's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
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