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

Thursday, 10 May 2012
Ian Robinson
9:18 AM

jb38, I checked both TV's last night (details below).


Multiplex BBC1 ITV1 ITV3 Dave Yesterday
Channel 23 26 25 22 28
Signal strength Medium Very Good Very Good Good Very Good


Multiplex BBC1 ITV1 ITV3 Dave Yesterday
Channel 23 26 25 22 28
TSID 1044 2005 3006 5040 6040
ONID 2339 2339 2339 2339 2339
Region London London London London London
Signal 100 100 100 100 100
Khz 490000 514000 506000 482000 530000
Bit error 43 2000 1751 2000 2000
Service ID 1044 2045 3eb0 5700 64c

I deleted all channels on the Samsung & manually tuned to only the Crystal Palace signals.
BBC1 seemed better, but if you look at the bit error at the time of test this will explain why. I have noticed that when BBC1 shows well ITV1 doesn't & vice versa. The bit error fluctuates to varying degrees.

link to this comment
Ian Robinson's 4 posts GB flag
Sunday, 20 May 2012
11:32 AM

Since the last update I have YESTERDAY, ITV4 & FILM 4 all breaking up all the time and non existent in bad weather & QUEST is never found on retune anymore either? Pre all the updates I had great pictures on everything, so surely my aerial hasn't just dropped in performance coincidentally around the same time as the digital updates? I am in Southampton and should be getting full freeview but am not. Is this what they call progress?? Any suggestions anyone please?

link to this comment
Steve's 1 post GB flag
Steve's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
Dave Lindsay

12:08 PM

Steve: The problem is that the Commercial channels are lower power horizontally. This is higher than all channels were before switchover, but the neighbouring high power Public Service channels (BBC, ITV1, C4, C5 etc) will be acting to desensitise your tuner, thus making it less sensitive to the (relatively) weaker ones.

See here:

ITV 3 | - independent free digital TV advice

The solution most likely to cure it is to switch your aerial to vertical polarisation.

Or attenuation "may" improve matters.

link to this comment
Dave Lindsay's 5,724 posts GB flag
Tuesday, 29 May 2012
8:40 AM

I receive Freeview from Crystal Palace, and before switchover CH22 was the weakest signal and gave most problems. Now after switchover I see CH25 is showing the weakest signal strength. I am curious as to why this is.

I am also experiencing very short but frequent freezing of the picture, sound is not affected though. These little "blips" are very brief and only last about a second but are extremely annoying. Does anyone have any suggestions?

link to this comment
Gary's 3 posts GB flag
Gary's: mapG's Freeview map terrainG's terrain plot wavesG's frequency data G's Freeview Detailed Coverage
Dave Lindsay

11:16 AM

Gary: It could be that the signal is now on the high side and that a little attenuation may help you. See:

Freeview signals: too much of a good thing is bad for you | - independent free digital TV advice

link to this comment
Dave Lindsay's 5,724 posts GB flag
Saturday, 16 June 2012
5:49 PM

Gary: If youre looking at the signal strength although important, Signal Quality (or bit error rate) is the more important for reception. It is an indication how much work the digital error correction the tuner has to apply to the data stream. Less error correction or better quality is what you are after.

There would have to be very extensive work to support DSO with probably a lot of hardware going live for the first time on the 4th and 18th April 2012. It is described on the Arqiva website as a man turning a big lever from on to off in one hall of equipment moving to the hall next door and turning another big lever from off to on. Analogue went off on came the new Digital Mux(s). All I can say it must a moved very very slowly between the halls.

Frequent freezing would suggest that in some cases, the data is so badly damaged it gives up trying to produce a picture. The data is no longer correctable; it unrecoverable and we have gone way beyond an error pixel or two.

During these periods of freezing, you have a reception problem. Getting the best signal you can into aerial would a good start. You dont say how close to CP you are and my own reception problems are documented under the interference section.

Good Luck

link to this comment
Robert's 20 posts GB flag
Friday, 22 June 2012
9:33 AM

Since retuning the TV on the 13th, all mux channels are OK except channel 55, which initially shows c. 50% signal strength and 100% quality but quickly drops to 0% for both (in stages of about 20% per second) and then stays at 0% until I reselect channel 55.

The PVR has no similar issues, and has a steady strength and quality for channel 55.

(Aerial lead is first into the PVR, and then RF out from there to the TV RF input)

Is this likely to improve on the next retune on the 27th?

link to this comment
Chris's 1 post GB flag
Thursday, 12 July 2012
Richard Randall
11:38 PM

Is anyone experiencing interference to the ITV Freeview channels in postcode SO15.

link to this comment
Richard Randall's 2 posts GB flag
Friday, 13 July 2012
9:51 PM

Ha, turns out the HDMI and RF cables must have been moved during cleaning and were too close together. All fine now.

link to this comment
Richard's 2 posts GB flag
Monday, 3 September 2012
5:15 PM

my freeview freezes when the neighbours use gardening equipment or heavy machinery what can I do to stop this

link to this comment
Kathleen's 1 post GB flag
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.