menuMENU    UK Free TV logo Freeview



Click to see updates

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

Tuesday, 25 January 2011
7:28 PM

Hurrah!!!!! Fixed it. I have also now got HD. Which I didn't have before. I realise I may only have it for a brief period, but tonight I have it all. Including HD :-) Yes, I know I need to get out more. Don't want to tread on anyone's toes as the newbie in here, but people may want to try this.

I read that sometimes cheap HDMI leads can cause interference. Mine was the one that came with the HD recorder box so I have no idea as to its quality. Swap to SCART it said. So I did, and ran an update for the 3 millionth time in the last 2 days, and low and behold, I have multiplex 1 back and HD.

Thanks for the info that is on this site it helped me narrow stuff down. I have saved it as a favourite.

Cheers Helen

link to this comment
Helen's 3 posts GB flag
Wednesday, 26 January 2011

8:55 AM

Helen: Glad we helped.

link to this comment
Briantist's 38,905 posts GB flag

9:00 AM

oyster: I would start by suspecting the internal aerial cables.

If you use a shared aerial system, contact the management company, as they will be responsible for ensure it works correctly.

link to this comment
Briantist's 38,905 posts GB flag
4:01 PM

ref earlier posting - the new set is in a bedroom and it is not possible to route its aerial through the booster/splitter.

link to this comment
Brian's 4 posts GB flag
Brian's: mapB's Freeview map terrainB's terrain plot wavesB's frequency data B's Freeview Detailed Coverage
6:16 PM

Many thanks Briantist (I hope you are being paid by someone for all your postings!?)
One follow up question/curiosity: from other similar postings why is it that this type of interference seems to always affect this ITV group first? Is there a known harmonic of another frequency?

link to this comment
oyster's 3 posts GG flag

7:42 PM

oyster: Multiplex A in pre-switchover areas is broadcast in the less robust 64QAM mode, see Freeview modes | - independent free digital TV advice .

link to this comment
Briantist's 38,905 posts GB flag
Thursday, 27 January 2011
9:55 PM

That explains it perfectly thanks! I come from Guernsey where we never had freeview before last November when switchover was in one night analogue off/digital on. That's why I am not familiar with digital interference! ITV is working again after fiddling with aerial connections. Thanks again.

link to this comment
oyster's 3 posts GB flag
Friday, 28 January 2011

7:50 AM

oyster: I'm glad to hear that you've got your channels back.

link to this comment
Briantist's 38,905 posts GB flag
Tuesday, 1 February 2011
10:28 PM

hi, I think i am having an interference problem. I ve had reception problems in my bedroom for the last year, but due to engineering work on emley moor and not watching much tv I never figured out what was going on.
After much messing about, the problem is that when the tv is one downstairs(showing a picture, standby is fine), i get interference upstairs on another tv. On the tv upstairs I can only view mux 1 channels, all the others loose signal. soon as the downstairs tv is put into standby all the channels, upsairs return.
The aerial to the bedroom comes in as an extension from the lounge which has the tv, which is causing the problem, next to it. The problem tv is running Sky HD and this problem has not been experienced on the tv which uses analogue, in a different room.
What can I do to rectify this? any help would be appreciated.


link to this comment
rob's 6 posts GB flag
Wednesday, 2 February 2011
Select more comments

Your comment please
Please post a question, answer or commentUK Free TV is here to help people. If you are rude or disrespectful all of your posts will be deleted and you will be banned.

Privacy policy: UK Free Privacy policy.