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Single frequency interference

What to do when several channels are missing, but they are all on the same 'multiplex'

What to do when several channels are missing, but they are all
published on UK Free TV

There are several different type of interference that cause problems. This page deals with the situation where:

There are two main causes of this type of intermitted interference: The current Freeview mulitplexes are shown in this diagram. If all of your missing channels are on a single row, you have "single frequency interference":



Local analogue interference

Local analogue interference is caused by household video devices that you can attach to a television such as:
  • Sky Digibox;
  • Video cassette recorder (VCR);
  • Personal digital video recorder (PVR);
  • Games console;
If you have any of these devices, you will need to work out which of these is blocking the reception of a Freeview multiplex by turning off the suspect device and then rescanning for channels on the Freeview box.

If powering off the device restores the Freeview channels from the blocked multiplex, you will need to either stop using the problem device's RF output by disconnecting the RF output cable permanently, or by changing the RF channel number that that device uses. See, for example, How do I change the RF output channel on a Sky Digibox?

You can find a list of the frequencies that are not in use at your location by putting your postcode into the My Freeview reception and looking under the "Free RF channels" section.

Non-wideband aerial in some areas

In some places you will need a wideband aerial to receive all the Freeview multiplexes. For example in Central Birmingham, the Sutton Coldfield has multiplex D on an 'out of group', so you cannot view Film4 or ITV2+1 without an aerial upgrade.

To find out if you need an aerial upgrade, see My Freeview reception.

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
Freeview reception has changed?5
Two frequency interference 6

Comments
Thursday, 15 September 2011
Briantist
sentiment_very_satisfiedOwner

7:31 PM

Dan: Sounds like you have a source of interference as listed at the top of the page.

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Briantist's 38,910 posts GB flag
Saturday, 17 September 2011
S
simon
9:16 PM

I have 2 tvs on 1 aerial. Pointing at sandy heath. One (42") can received Dave okay. The other (24"?) Has lost it recently. Any ideas

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simon's 2 posts GB flag
Wednesday, 21 September 2011
P
Peter
12:37 AM
Sutton Coldfield

Hello. I am only 6km from the Sutton Coldfield transmitter at B76 2SA. My freeview (humax) box with a new digital aerial can pick up the ordinary BBC channels, which work Ok, although the signal strength meter is only 30%. The HD channels keep breaking up - the picture freezes and pixellates. The meter says there is only 10% signal strength on the HD channels. The digital aerial is in the loft and pointed at the SC transmitter. How come the signal is so low? I was hoping this would improve after the retune tonight (21 September) but if anything the signal is weaker. Can you help

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Peter's 1 post GB flag
Peter's: mapP's Freeview map terrainP's terrain plot wavesP's frequency data P's Freeview Detailed Coverage
Saturday, 24 September 2011
A
Andy Smith
10:29 PM
Norwich

Hey. I have lost sky news channel, dave etc and the other channels in row 'C' as described above. These channels were on channel number 68. My local transmitter is Tacolneston. Any clues on how to get them back as i have retuned more times than i care to remember. Thanks in advance for any help.

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Andy Smith's 1 post GB flag
Andy's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
Monday, 26 September 2011
K
KEVIN GARDINER
sentiment_satisfiedBronze

5:40 AM

Peter: your location is a mere 4 miles from Sutton Coldfield and your signal strength at 10 metres, or chimney pot installation is roughly 88db. This means that after digital switch over on wed 21St September, you are now experiencing signal overload. please refer to Briantist advice. Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice .

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KEVIN GARDINER's 68 posts GB flag
Tuesday, 27 September 2011
K
Ken
8:16 PM
Hailsham

Hi, I live in Hailsham in East Sussex, due south of the Heathfield transmitter. I have just installed a "Log 40" aerial from ATV with new double screened cable and this is at a height (8m) where there is a line of site view of the transmitter. I know the transmission from Heathfield to the south is seriously attenuated pre DSO, but I get useable signal (good quality, low signal stength reported by the STB - Philips DTR210) on MUXs 1, 2 and C, but A(C48), B(C47) and D(C51) all report strong signal, zero quality. Could this be co-channel interference from BBC1 (on C49) from the same transmitter. I have no other UHF equipment nearby - VCR is turned off, not Skybox etc. If so then I guess I will just have to be patient and wait until next summer!

Thanks

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Ken's 1 post GB flag
Ken's: mapK's Freeview map terrainK's terrain plot wavesK's frequency data K's Freeview Detailed Coverage
Thursday, 29 September 2011
J
John Halliday
12:58 PM

Hi, I live in CH66 area - until a few days ago C4 was perfect, however since prompted to retune it has moved and picture quality is dreadful/unwatchable - checked connections etc and all is OK
Any asdvice please?

Thanks

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John Halliday's 1 post GB flag
Briantist
sentiment_very_satisfiedOwner

10:35 PM

John Halliday: It is hard to say without a full postcode, can you please see Freeview reception has changed? | ukfree.tv - independent free digital TV advice for general suggestions?

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Briantist's 38,910 posts GB flag
Briantist
sentiment_very_satisfiedOwner

10:36 PM

Ken: Basically, yes, you will have to wait until 13th June 2012 when you will be supplied with signals from Heathfield.

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Briantist's 38,910 posts GB flag
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