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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
Saturday, 22 June 2013
K
KMJ,Derby
sentiment_satisfiedGold

2:01 PM

lizzie: Check that the BBC multiplex is tuned to C50 from Winter Hill, rather than C26 (Haslingden) or C45 (Moel-Y-Parc). It is possible that your reception is being disrupted be trees in leaf growing in the signal path. What is reception on Sky News like? This service uses an adjacent frequency, so could also experience similar problems. There is very little tropospheric ducting occuring at the present time in the UK, so interference from distant transmitters can be ruled out. If you have an HDMI cable connecting the DVD to the TV try moving its position relative to aerial flyleads in case of any interaction between them.

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KMJ,Derby's 1,811 posts GB flag
B
Bakatcha
2:23 PM

lizzie: Same problem, 2 weeks now, Only on BBC Channels, Retuning does not cure.
Am in NG2

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Bakatcha's 2 posts GB flag
K
KMJ,Derby
sentiment_satisfiedGold

3:04 PM

Bakatcha: Similar reply. Check that the BBC channels are being received on C49 for Waltham as NG2 also has signals on C43 (Sutton Coldfield), C27 (Kimberley) and C22 (Belmont). I assume that your problem began when the BBCA frequency changed at Waltham. If you are using a communal aerial check if neighbours in the same block are having the same problem. If they are, it might be necessary to contact the landlord or property management company for an adjustment to be made to the aerial to let the new frequency through. If it is your own aerial there should be no problem if you used to receive BBC East Midlands on Freeview before DSO in 2011, as C49 was in use then. Additionally, check for trees in the signal path, Sky box or VCR RF modulator set around C49, or interference from HDMI cable if you use one.

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KMJ,Derby's 1,811 posts GB flag
B
Bakatcha
4:17 PM

Bakatcha:
All BBC on C49
Reception showing as very good.
Not a community aerial
No HDMI cable near affected TV
No sky box
No large trees
I did not have this problem immediately after Anologue switch off. Only stared in last few weeks

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Bakatcha's 2 posts GB flag
Monday, 1 July 2013
P
pete savva
12:59 PM
Canterbury

my neighbour is old i spent 45 min round her house trying to sort out her tv with her rental provider as she lost all her chanels ive been told by her today that the engineer stated the problem was with the mast at chartham her postcode is ct13ul Alfred close in canterbury, ive tried retuning but still have no signal, is there a problem with the mast

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pete savva's 1 post GB flag
pete's: mapP's Freeview map terrainP's terrain plot wavesP's frequency data P's Freeview Detailed Coverage
Dave Lindsay
sentiment_very_satisfiedPlatinum

2:10 PM

pete savva: None has been reported.

If there is an amplifier involved - which is also applicable if it's a communal aerial - then this could have failed. Do not assume that because its power light is on that it is functioning normally.

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Dave Lindsay's 5,724 posts GB flag
K
k
2:54 PM
Diss

Can anybody tell me if there is a problem with signal in Diss Norfolk?

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k's 1 post GB flag
k's: mapK's Freeview map terrainK's terrain plot wavesK's frequency data K's Freeview Detailed Coverage
Dave Lindsay
sentiment_very_satisfiedPlatinum

3:03 PM

k: Presumably you are using the Tacolneston transmitter. According to Digital UK, this week Tacolneston's TV service is "liable to interruption".

See digitaluk.co.uk/engineeringworks and select the "Anglia" region.

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Dave Lindsay's 5,724 posts GB flag
Tuesday, 9 July 2013
P
Peter Sunderland
11:23 PM
Sherborne

Hi
Has anybody any ideas on the following.
Since having to retune to the Stockland hill transmitter a couple of week ago the BBCA group is Ok good signal strength & quality but the BBCB, D3+4, ARQB are only 7 out of 10 signal strength & 5 out of 10 quality. SDN varies sometimes good sometime poor & ARQA has disapeared.
Tried a booster only slight improvement. With current weather often the picture is breaking up or showing no signal but BBCA still good.


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Peter Sunderland's 2 posts GB flag
Peter's: mapP's Freeview map terrainP's terrain plot wavesP's frequency data P's Freeview Detailed Coverage
Tuesday, 30 July 2013
T
Tony
10:09 PM

I am in the Granada area and my freeview reception is perfect most of the time but once or twice a day it breaks up badly for about 5 minutes. If I flip to analogue channels I can see some interference on BBC2 and CH4 frequencies so I suspect something is interfering. I have read that no G4 tests are being run in my area. Anybody have any ideas?

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Tony's 1 post GB flag
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