Single frequency interference
Brian Butterworth published on UK Free TV There are several different type of interference that cause problems. This page deals with the situation where:
- Freeview reception is perfect or near-perfect most of the time
- Several channels are missing, but they are all on the same 'multiplex'
Local analogue interference
Local analogue interference is caused by household video devices that you can attach to a television such as: 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?
Friday, 18 November 2011
M
Mark Fletcher3:08 PM
Halifax
Neil,Scunthorpe.There were atmospheric conditions/inversion affecting much of eastern UK (a few like myself further west too !) during the last few days or so and Sunday night 13 Nov 2011 was no exception.There were no direct transmission problems whatsoever with the Belmont mast at that time,the inversion effect was the cause of Belmont's on and off signals,and as three of my mux's are from Belmont itself BBCA fr 22,D3+4 fr 25,SDN fr 30,i too suffered from loss of signal on and off,but i fiddled with the manual scan function (signal booster for a time switched on) and picked up temporarily SDN fr 31 from Sandy Heath,all but the BBCB (HD) mux's from Waltham and even Digitenne fr 32 from Leeuwarden in Holland/Netherlands,i knew it was atmospheric conditions itself.
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Mark's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Sunday, 20 November 2011
B
Ben Denise4:58 PM
Deal
I live at CT14 8BY Kingsdown, Deal, Kent - During High Pressure weather systems we get interference from Netherlands tv - sometimes Netherlands ch 1,2,3 and 4 take over from BBC 1, 2 etc and that is without retuning and having a high gain aerial pointing in the correct place. Analog Tv is fine on all the original channels.
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Ben's: mapB's Freeview map terrainB's terrain plot wavesB's frequency data B's Freeview Detailed Coverage
B
Ben Denise5:32 PM
Deal
Also Kingsdown is out of the coverage area of Dover so can i stop paying for a TV licence.
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Ben's: mapB's Freeview map terrainB's terrain plot wavesB's frequency data B's Freeview Detailed Coverage
Ben Denise: You cannot stop paying your TV Licence if you cannot receive a terrestrial signal. The Licence doesn't guarantee availability of broadcasts in any or particular modes.
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S
Simon11:51 PM
Tarporley
I have a loft antenna. My problem is erratic loss of quality on the BBC multiplex. Quality sometimes drops to 90/80/70/60 or even 40 which sometimes causes pixelation etc. All other mux are perfect. I am using the Moel transmitter as we have hill in the way of Winter Hill. The BBC used to be fine until the September retune. I've done the wipe and research on the box. Any ideas ? Thanks.
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Simon's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
Monday, 21 November 2011
M
Mark Fletcher12:50 AM
Halifax
Simon,Tarporley.In relation to the loss of quality you mentioned on the 20kw powered BBCA mux on fr 45 on the Moel-Y-Parc main transmitter,one possibility could be that since September 2011 when Sutton Coldfield mast became all digital,their 200kw powered ArqA mux also on fr 45 may in certain atmospheric/inversion conditions travel further than usual and occasionally totally overwhelm the 10 times weaker BBCA Moel-Y-Parc multiplex.Or,single frequency interference under normal circumstances could be the other cause that i mentioned above.Just out of interest look up under Freeview on Moel-Y-Parc transmitter especially a few posts texted from Sunday 13 November 2011 onwards,the answer most likely could be inversion/atmospheric conditions !
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Mark's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Simon: On suggestion is to resite your aerial.
I too am having issues with picture freezing with a loft aerial. I had no such issue prior to switchover and watched digital TV all the time!
My signal is very strong (90% on my Sony). I have moved the aerial and it has cured the problem on the worst mux, but it has now shifted to another one with another not far behind!
I am thinking I will have to move it again.
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Simon: Mark Fletcher makes a very good point. You might turn your aerial to Sutton Coldfield's direct, retune your box and pick up its ArqA on C45.
I note that the Digital UK coverage predictor suggests that you will have a good chance of picking up all Sutton Coldfield's muxes.
Google Streetview shows most aerials apparently pointing to Sutton Coldfield. I can spot one on Winter Hill. They are all large things on tall masts.
Moel-y-Parc is more or less at right-angle to Sutton Coldfield. You could try constructing a shield to put in your loft space at the side of the aerial that faces Sutton Coldfield. It will need earthing. Maybe some wire mesh will do the trick.
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