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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
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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

Sunday, 11 September 2011
5:53 PM

hi jb
yes block c with pick tv and dave e4+1 etc. will try a manual tune.

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louise's 4 posts GB
8:29 PM

Our lounge TV has always received Film4, Viva etc, but no other TVs in the house can. The loft coaxiel supplying the lounge was about 10 metres long (all coiled up), so as an experiment, I cut it, put a splitter in and ran the 10 metres to the bedroom TV. Not only did this not achieve Film4 for the bedroom.....but it also lost Film4 from the lounge!!! In frustration, I took the splitter out and rejoined the lounge connection returning it to a single supply believing the splitter caused the loss, but Film4 still didn't return ???
The only assumption that I can make is that when the 10 metre slack was all coiled up it somehow assisted the lounge reception...does that sound mad ?
I don't understand how shortening the cable has lost my lounge Film4 ?

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Steve's 1 post GB
Monday, 12 September 2011
6:19 PM

hello jb38
i have done the manual tune and i have managed to get the channels come up. they have gone from channel 11 for pick tv too 813. and the rest are 800+ saying this they are still not watchable because it says no or bad signal.
any ideas?

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louise's 4 posts GB
Tuesday, 13 September 2011

7:42 AM

Steve: The very act of cutting and rejoining a cable will incur a signal loss. I would hang on for a week on Wednesday when there will be a significant increase in the signal.

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Briantist's 38,844 posts GB

9:19 AM

louise: If you want the channels on the correct numbers, you will have to clear all the channels first and then do a manual tune.

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Briantist's 38,844 posts GB
Wednesday, 14 September 2011
8:15 PM

Hi. Following a re-tune of digital TV, block 2 channels (Channel 68 = ITV/Ch4 etc) have disappeared. Post code = OX15 4AS

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Dec's 1 post GB
9:09 PM

Did a complete retune on 14/09/11 as instructed but I am now receiving no mux 3 channels, Pick TV, Dave, Sky News etc.
This is the same on 2 other sets in my house.

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Dan's 2 posts GB
Thursday, 15 September 2011
4:56 PM

Briantist - Yes I did a first time install on all 3 sets (on more than one occasion) but it's the same channels missing on every set. The annoying thing is they were all there on 13/09/11. So much for technological progress.

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Dan's 2 posts GB
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