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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.

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Two frequency interference 6

Wednesday, 13 February 2013
2:53 PM

I receive my tv transmissions from the Waltham mast. My Sony tv on autotune finds all channels but ITV is for Lincolnshire not East midlands resulting in incorrect local news programs and pixellating (no pixellation on other channels) Can anyone tell me correct frequency to manually tune ITV to sort this problem?

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Mike's 1 post GB flag
Mike's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Dave Lindsay

3:04 PM

Mike: ITV from Waltham is on C54 (737.8MHz).

The other alternative is to have the aerial unplugged for lower channels which will prevent it from finding the East Yorks & Lincs signal from Belmont. Get the aerial in at about 50% or C45.

Once you've done this, go to the manual function and add C29 (538MHz) which is COM4 (ITV3 etc) from Waltham.

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Dave Lindsay's 5,724 posts GB flag
Wednesday, 27 February 2013
11:25 PM

Film4 etc (com6/arqB) have variable signal quality throughout the day, from watchable to 'no signal' on both my Sony TV and BT box. The aerial is new and the signal amplified for house distribution.
Is this one type of single frequency interference or should I be looking elsewhere for the problem?

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Trevor's 1 post GB flag
Trevor's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
Friday, 29 March 2013
Liz Biron
8:50 PM


Despite endless factory retunes, we have had no reception of any BBC channels in the centre of Taunton since the retune. We are also missing some but not all channels from the multiplex with ITV3, five star and five USA on, but not all becuase we do have E4 channel 28. I am absloutely dumbfounded by fact that nothing has yet been done about it and how little we are being told - or may be that's going out on BBC channels! One of our neighbours has all channels, another like us is missing loads. Is the issue with our aerial? if so, why weren't we warned that this will be a problem. We had perfect reception on all BBC channels before the retune.

Please respond with likely timescales for resumation of normal service, else what we need to do to get reception again.

Unbelievably pissed off.

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Liz Biron's 1 post GB flag

10:03 PM

Liz Biron: Can you give some details about your aerial? Is it a communal aerial, or if it is your own is it a single aerial connected directly to the receiver, or is it combined with a second aerial in order to receive a relay plus a main transmitter or two different main transmitters? If you are trying to receive from Mendip you are missing C48 and C49 for some reason. If manual tuning is available on your tuner try entering each of the missing frequencies, taking note of signal strength and quality for each before storing any channels, that is, if any are found!

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KMJ,Derby's 1,811 posts GB flag
Saturday, 27 April 2013
Chris Johnson
3:29 PM

Dear UK Free TV,
I own a Humax PVR 9150T. Generally it's great. I have a problem with poor quality on some channels. Eg ITV4. The signal strength on all channels is about 75%. BBC1 etc are 100% quality. ITV4 Etc cycles between 10% and 100% quality. The same signal comes out of the humax box into the TV and the quality is fine with the TV.

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Chris Johnson's 1 post GB flag
Dave Lindsay

3:36 PM

Chris Johnson: If this is a request for help then as it is a signal related issue you will have to provide an idea of your location, preferably in the form of postcode or nearby postcode (such as that of a shop).

The Commercial (COM) channels which carry ITV4 and others do not have as good a coverage as the other Public Service (PSB) ones which carry BBC, ITV, Channel 4, Channel 5 and others. This is the reason why knowledge of your location is imperative.

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Dave Lindsay's 5,724 posts GB flag
Tuesday, 4 June 2013
2:28 PM

Mendips TX - since retune in swindon com4 mux 48 is zero signal strength on stb/VCR and no tune on TV.
Oxford TX - gives 0/4/5/6 out of 10,rapidly changing signal strength on com4 mux 50

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ALAN HILL's 3 posts GB flag
Saturday, 8 June 2013
k. spackman
3:48 PM

i keep loosing signal to bbc programmes in the evening from 9pm onwards until the next this is caused by single frequency interferance and what can be done about it, i have retuned my freeview box. i live in sn7 7dq on the oxon and berks transmitter.

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k. spackman's 1 post GB flag
k.'s: mapK's Freeview map terrainK's terrain plot wavesK's frequency data K's Freeview Detailed Coverage
Saturday, 22 June 2013
11:41 AM

All bbc channels really badly pixelating, unwatchable at the moment. Could it be interference from weather? Or would all channels be affected? Picture has gradually been getting worse over last week. Have tried to retune, but no improvement. No new equipment in the house, freeview both within tv and dvd showing same problem. Live in m19 2hg postcode - grateful for any help. Aerial on roof of 3 storey house. Thanks

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lizzie's 1 post GB flag
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