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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
Tuesday, 6 December 2011
J
jb38
sentiment_very_satisfiedPlatinum

11:46 PM

Dave Lindsay: The point is though Dave, that the erratic element of signal variation has to be caused by something that moves with a reasonable speed, which can as was suggested be caused by vegetation of sorts (trees / bushes) blowing about in a breeze.

Another possible reason can be if a person is receiving a signal from anywhere within about 10 miles or so of flight paths used by aircraft, as although a digital signal has an element of robustness against this sort of thing it isn't by any means foolproof.

Buildings of course can also cause signal reduction problems, or even in some cases the reverse by providing a good stable reflected signal, but whether it be on the plus or the negative side, its always stable.

This all being said excluding the always present possibility of the problems experienced being caused by sources of interference, like mains borne from devices like central heating thermostats and such likes, or fridges / freezers thermal cut outs etc.





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jb38's 7,179 posts GB flag
Wednesday, 7 December 2011
T
Tom Lewis
12:49 PM
Ipswich

Reception lost since Norfolk Freeview switch-on:
Channels :- ITV4,ITV4+1,Film4 And RT even after retuning.

Why and how can I solve problem

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Tom Lewis's 1 post GB flag
Tom's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
T
Tony Liddiard
1:59 PM
Hook

I live at RG29 1AR, Odiham which is directly on the line between Guildford and Hannington.
I understand that the digital signal strength from Hannington in the direction of Guildford is at reduced power to avoid interference with the Guildford analogue service.
Hannington analogue will be switched off in early February but Guildford switchover a couple of months later.
We are being told that the signal strength after switchover will be significantly improved. What confidence can you give that this will apply to the Hannington transmissions in the direction of Guildford

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Tony Liddiard's 3 posts GB flag
Tony's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
Dave Lindsay
sentiment_very_satisfiedPlatinum

2:05 PM

Tony Liddiard: The reason that Hannington is as you say it is now is because the frequencies used for its digital service are the same as Guildford's analogue one.

Come switchover, Hannington will broadcast digital TV using the same frequencies that it used for analogue TV (as is the case for most transmitters), hence the problem of transmitters clashing won't exist.

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Dave Lindsay's 5,724 posts GB flag
R
Roy
6:09 PM
Tonbridge

Roy: jb38, Dave - Thanks for the further advice. Aerial with 'dodgy' reception is on the side of the building so several feet lower than the good one which is on a chimney. Recent deterioration could mean some external influence is at play although I cannot spot anything. Sounds like reconfiguring the aerial(s) is probably the way forward. Thanks again for the advice.

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Roy's 6 posts GB flag
Roy's: mapR's Freeview map terrainR's terrain plot wavesR's frequency data R's Freeview Detailed Coverage
Friday, 9 December 2011
M
Mack
5:21 PM

My LG tv with a built-in free view box doesn't appear to register any signal at all from my Ross free-sat dish. The Ross set-top box shows a solid signal strength from the dish and I can watch most freeview channels, but obviously I can't tune any of them into my tv. Does the Ross dish require me to use the Ross set-top box or is there some way I can get the box built into the LG TV to recognise the dish? Many Thanks in advance.

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Mack's 1 post GB flag
Thursday, 15 December 2011
J
John Beeston
12:01 PM

John Beeston:
Dave Lindsay - thanks for your reply on 30.11.11, it was very helpful & have now sorted things out.
I guess as surrounding areas switch over this will happen more & more. I saw on another post that Bluebell Hill cannot transmit HD. Will this change after the final switchover next summer?
It's all confusing as we only live about 5 miles from the Heathfield mast yet have to have our signals bounced all over. Thanks again anyway.

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John Beeston's 8 posts GB flag
Dave Lindsay
sentiment_very_satisfiedPlatinum

12:37 PM

John Beeston: Before switchover, HD services are not carried by transmitters with the exception of four (two of which have now switched). Your only possibility is that if you can receive Sudbury (to a degree - i.e. perhaps with intermittent break-up), then you might be able to receive its HD service. Try manually tuning to C47 and see if your TV picks up the Sudbury HD signal.

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Dave Lindsay's 5,724 posts GB flag
Saturday, 17 December 2011
M
Mike
11:34 AM

Over the last few days, I am receiving pixillation on Channels 12,15,21,22,24,32 and 48 - MPX 6 on Craigkelly. All other MPXs give very good picture. Any ideas?

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Mike's 1 post EU flag
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