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?
Saturday, 3 December 2011
E
Elizabeth6:09 PM
Reading
I have 3 TV's all freeview, why does the kitchen not receive ITV3 - it says it is "out of range"! yet the other 2 are fine. I have tried to retun manually but do not know the no. Any suggestions please?
link to this comment |
Elizabeth's: mapE's Freeview map terrainE's terrain plot wavesE's frequency data E's Freeview Detailed Coverage
J
jb386:52 PM
Roy: Well on looking at the trade view predictor using the code provided only Dover is shown as being capable of providing reasonably good reception, Bluebell Hill being not that good by being variable on every multiplex but one (MuxD Ch39) and with no HD being possible.
To be honest about it I would just manually tune both TV's to the same station, which if its Dover you are receiving from is Mux channels 68 / 61 / 60 / 62 / 55 / 58, the manual tuning menu being accessible via "installation" or "set up" etc depending on what brand of equipment you have.
Just to be sure that the channels given are actually what you are receiving on the "Kent" TV, you should go into its tuning menu / signal check screen whilst its on each in turn: BBC1 / ITV / HD (if used) / ITV3 / Dave / Film 4 noting the Mux channel number shown associated with the signal level, then cross check them against the numbers given, if any errors just use what you obtained from the Kent TV.
link to this comment |
J
jb387:02 PM
Elizabeth: You are indicated as only being able to have good reception from Hannington, the Mux channel used for ITV3 on that station being Ch40, so go into the tuning menu on the set that hasn't picked up ITV3 and manually tune it in by entering Ch40 in the search box, storing what's received if not done automatically.
Before you do that though try searching up in the 800 ranges of EPG channels just in case ITV3 has been pushed up there during scanning.
link to this comment |
Elizabeth: Another suggestion is to take the kitchen TV to another aerial point and try tuning it there and then returning it to the kitchen.
link to this comment |
Roy: You could try taking the TV tuned to Bluebell Hill to the other aerial point. Then run the auto-tune scan and take it back again.
This may or may not work. It depends on how the TV selects the transmitter to go with. It could be that the aerial of the TV which is "Kent" doesn't pick up Bluebell Hill as well which could be why moving it temporarily might work. It's all ifs, buts and maybes. You will have to try it and see if it works.
link to this comment |
Sunday, 4 December 2011
N
Nicki Hardy10:43 PM
Camberley
Hi. Live in Camberley GU17 9EY, and have suddenly tonight lost all digital channels on all 4 TV's in the house.One is connected to digibox, the others IDTV/Freeview. Only one can be viewed in analogue mode but the channels are preety poor, except BBC1/2. We haven't been up in loft to check that the cables not fallen out from the aerial or anything daft like that yet. Any suggestions to try out before we go up to loft (which is suspect isn't the problem)?
link to this comment |
Nicki's: mapN's Freeview map terrainN's terrain plot wavesN's frequency data N's Freeview Detailed Coverage
Nicki Hardy: The fact that all TVs have failed and that (most) analogue is poor suggests a fault with your amplifier, aerial or the cable which joins it. So I think that there is nothing that can be done without going up into the loft.
link to this comment |
Tuesday, 6 December 2011
R
Roy7:51 PM
Tonbridge
Roy: Thanks for tips jb38. I did exactly as suggested - hooked up my LG TV and Humax freeview recorder to the 'good' aerial, retuned and everything works just fine. The humax is most informative and shows Mux channel 68 as 'Kent'. I then took the units back to the problematic aerial and without retune the humax displays channel 68 as 'Bluebell Hill'. Interestingly, most of the time when I go to return the signal strength is about 40% but the quality starts at 100% then drops to 1% after a few seconds. On a later attempt the quality was zero and the strength was switching from 10% to 0% every few seconds. I am starting to wonder if there is local interference near the problem aerial I turned off very electrical device in close proximity without improvement. any further thoughts? My house used to be two separate properties which is why I have the two aerials. Would be hassle and cost to reorganise.
link to this comment |
Roy's: mapR's Freeview map terrainR's terrain plot wavesR's frequency data R's Freeview Detailed Coverage
J
jb389:41 PM
Roy: Re: update. The point is than when dealing with reception in difficult areas experimenting by moving the aerial about in the horizontal plane can in many cases make quite big differences in reception, although to get it correct you really require to use a small portable Freeview TV beside you in the loft (if referring to this) for instant feedback on actions taken.
As far as the erratic signal level is concerned, this always indicates that the signal being received is being warped in various ways by being either blocked or reflected by objects such as trees etc, and sometimes this effect can even be experienced if located anywhere within site of a main carriageway where high sided vehicles pass along.
Unfortunately though there isn't much that can be done to help in these type of situations except by trying to keep the signal running at as high a level as possible, this done by using an amplifier mounted near to the aerial, as a system running with a low level of signal is always more prone to suffering from picture glitches etc than is experienced with higher levels of signal, as unlike the case with low levels of signals, the higher one has further to fall before it drops under the reception threshold of the receiver.
If you find you cannot get the inferior aerial to operate any better I would abandon it and fuss about with the other aerial, possibly even feeding it into a two way (or more) powered splitter and using its outputs to feed all other rooms.
link to this comment |
Roy: Are there any trees that could be in the way?
At 94degrees, could it be other buildings on the lane that are in the way?
link to this comment |
Select more comments
Your comment please