menuMENU    UK Free TV logo Freeview

 

 

Click to see updates

Freeview reception has changed?

Why should my Freeview reception change when I have not changed anything?

Why should my Freeview reception change when I have not changed
published on UK Free TV

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?
How do I get a test card with Freeview1
I would like to know if it is possible to receive UK terrestrial Freeview servic2
I have been told I would receive too much singal from my Freeview tansmitter as 3
Can my Freeview box receive more than one BBC and ITV region?4
Is it true that my 87 year old mother is entitled to a FREE upgrade when the ana5
In this section
Official aerial installers guide to the TV spectrum future1
Which free digital TV system will give me the most reliable reception?2
High pressure causing channel loss through "Inversion"3
Digital Region Overlap4
Two frequency interference 5
Single frequency interference6

Comments
Thursday, 5 May 2011
M
Mike Dimmick
sentiment_very_satisfiedPlatinum

6:28 PM

nat: Have you checked that all the cables are plugged in, and that they don't seem to be broken? That, or a dislodged aerial, are the most likely causes.

link to this comment
Mike Dimmick's 2,486 posts GB flag
D
David
6:39 PM

Thank you Mike. Yes.Multiplex 2 is the problem. Is Guildford transmitter new this week ? Everything has been fine for some years now with just occasional problems and usually only lasting for a few hours. This now seems a permanent problem over the last 3 days. Would a manual retune (rather than an Auto retune) only selecting Hannington Channels, help resolve the problem ?

link to this comment
David's 14 posts GB flag
Friday, 6 May 2011
M
Mike Dimmick
sentiment_very_satisfiedPlatinum

12:46 AM

David: The Guildford transmitter has been there since 1972 and Hannington's digital transmissions have always clashed with it (at least as far back as 2001, which is the furthest back that).

The broadcasters did increase the power over the years: Mux 2 started out at 5 kW, was increased to 10 kW in 2000 and then increased again to 20 kW in 2004.

The problem is that the transmissions are on the same frequency. The receiver sees the combined result of adding Hannington's digital to Guildford's analogue, which - from time to time, depending on what's being transmitted on both, and on weather conditions - causes too many errors for the box to be able to correct. Manual tuning will not help at all.

Of course, it's possible that some other issue has been slowly deteriorating and has now reached the point that Mux 2 has stopped working - but as I said, the prediction for that location is already non-existent so it's really hard to say whether you losing it is down to some changes in the interference level, or whether it's an equipment problem.

link to this comment
Mike Dimmick's 2,486 posts GB flag
Monday, 9 May 2011
D
Dave Burns
6:08 PM
Hertford

I am at SG14 2TN (Hertford). Apparently I am serviced via the Crystal Palace transmitter. Our Switchover is not for another 12 months. Like many of the people on this blog thread, signal quality to my iDTV's has become either poor or non-existant over the last 3 weeks. For the previous 12 months all channels have been just fine and working perfectly. I have changed nothing on either of the 2 iDTV's in my house, other than undertaking the recommended automatic re-tuning process. No success. Reception signal is now so poor I can not even receive ITV1, Ch4 or Ch5 let alone the Freeview channels. I have also totally lost analogue connection. I spoke with UKDigital who told me that they could detect poor signal and that I should expect no Freeview channel reception for another year. So how come I have been getting perfect Freeview for the last 12 months? UKDigital could not answer that question. So they put me in touch with ARQIVA who manage the transmitters. ARQIVA told me there is no problem with the Crystal Palace kit and I should be getting a strong signal as far as they are concerned and were at a loss as to why UKDigital would be telling me otherwise. WHAT IS GOING ON? Seems to me from this blog thread and other similar ones that hundreds (possibly thousands?)of people are experiencing the same or similar degradation in signal all at once, all since mid/end April and in several different parts of the UK. We can't all be experiencing aerial malfunctions or raging Isobar pressures all at the same time, surely?

link to this comment
Dave Burns's 1 post GB flag
Dave's: mapD's Freeview map terrainD's terrain plot wavesD's frequency data D's Freeview Detailed Coverage
M
Mike Dimmick
sentiment_very_satisfiedPlatinum

6:41 PM

Dave Burns: If you have also lost analogue reception, there are two possibilities:

1. Your aerial was actually pointing at Sandy Heath, which has switched over. If you lost BBC Two analogue on 30 March and the others on 13 April, this is the most likely explanation.

2. Something in between the aerial and your TV has become disconnected. Or, the aerial is no longer pointing in the right direction or been damaged.

Check the direction of the aerial. If it's pointing roughly north, that's Sandy Heath. Crystal Palace is to the south. Hemel Hempstead, another possibility, is to the west - this requires the aerial elements to run up-and-down rather than side-to-side.

Break-up can be caused by too much as well as too little signal. If you have an amplifier, try removing it or turning it down: although you're not really close enough for that to be the issue, a very large amount of amplification or aerial gain can still cause problems.

The amount of interference on any given channel is changing all the time as different transmitters switch over, both here and overseas. While signals don't travel that far during the day in normal weather, they travel further at night and in high-pressure conditions, which we have had.

It's possible that if the aerial is pointing to Sandy Heath, that the TV has still tuned in services from Crystal Palace. If it didn't do this before, the most likely reason is that your TV doesn't support the 8K mode which is used after switchover. Check the list at http://www.digitaluk.co.uk/2kequipment , though this is only a list of some equipment that is known not to work and there may be others. If this is the case, or if the TVs are from before about 2005, check with the manufacturer, or check that the manual lists 8K mode in the specifications.

The other reason for the wrong signals being tuned in is that a lot of equipment stores the first version that it finds, i.e. the versions on the lowest frequencies. The frequencies are lower at CP than at Sandy Heath, but they always have been, which is why I think it's unlikely that this is the cause.

link to this comment
Mike Dimmick's 2,486 posts GB flag
Wednesday, 11 May 2011
A
a coe
3:47 PM
Gravesend

can you tell me the manual resetting details for channel 4 crystal palace my post code
is da11 9qh thank you.

link to this comment
a coe's 3 posts GB flag
a's: ...
P
Paul Rigby
7:30 PM
Purfleet

I have a Bush BTU 160 DTR free-view box that is causing me problems. Every time I change channel I lose signal and have to power on and off with the remote to regain signal.
I live in a small block of flats in Purfleet RM19 1TF that has a roof top aerial and when I receive a signal the picture is near perfect.
The box has twin scart and twin aerial sockets and I have tried every combination possible.
This is the second box I have tried with no luck.
In order to record programmes with any certainty I need to make sure the box is receiving the signal and leave it set on that channel with the box powered up.
Please help


link to this comment
Paul Rigby's 3 posts GB flag
Paul's: mapP's Freeview map terrainP's terrain plot wavesP's frequency data P's Freeview Detailed Coverage
Briantist
sentiment_very_satisfiedOwner

8:15 PM

Paul Rigby: When you say "the second box I have tried" was that also a Bush BTU 160 DTR?

You are predicted to get an excellent service from the Crystal Palace transmitter at your location.

link to this comment
Briantist's 38,915 posts GB flag
Thursday, 12 May 2011
P
Paul Rigby
2:51 PM

The second box was exactly the same make and model

link to this comment
Paul Rigby's 3 posts GB flag
P
Paul Rigby
2:53 PM

Sorry...both boxes were the same make and model. Had same problems with first box and got an exhange

link to this comment
Paul Rigby's 3 posts GB flag
Select more comments

Your comment please
Please post a question, answer or commentUK Free TV is here to help people. If you are rude or disrespectful all of your posts will be deleted and you will be banned.







Privacy policy: UK Free Privacy policy.