Freeview intermittent interference
Brian Butterworth published on UK Free TV There are several different types of interference that cause problems. This page deals with the situation where:
- Freeview reception is perfect or near-perfect most of the time
- The audio on TV and radio channels mutes momentarily a few times each minute
- The picture on a Freeview channel freezes a few times each minute
There are two main causes of this type of intermittent interference:
- 'Induction' interference
- Mobile phone interference
Induction interference
Induction interference is caused by mains-powered household devices that contain a large motor, such as:- Washing machine;
- Tumble dryer;
- Central heating pump or combination boiler;
- Fridge;
- Freezer;
- Power tools (drills, jigsaws etc)
- Vacuum cleaners;
- Water pumps;
- Automatic doors
You can identify if one or more of these devices is causing the Freeview reception problem by powering off the devices.
If one of these devices is causing the problem, then the reception problem can usually be solved by using a mains filter device and use it on the Freeview boxes mains connection.
Such as device is this: Maplin: 6-Way Flat Screen and HDTV Surge Protector and Mains Filter.
Mobile phone interference
If you keep a mobile phone by your Freeview box or digital television, keep it further away!This also applies to other transmitters such as baby monitors, video senders, walkie talkies, and portable phones.
Help with Freeview, aerials?
Wednesday, 14 November 2012
N
Nicholas Willmott2:50 PM
Valerie, if you are picking up from Rowridge, is your aerial still horizontal, or have you had it reset to vertical? If it's still horizontal, perhaps it would be worth getting it set vertical, in order to get the COM muxes at full strength (same as the PSB muxes).
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VALERIE: Further to Nicholas Willmott's comment, I had wondered whether it was worth a shot at switching polarisation.
Rowridge transmits horizontally and vertically and has done so since switchover. Some channels aren't as strong horizontally, but this does not include those of the BBC which are PSBs.
I'm not an expert, but I wonder whether the affect of the trees may be different with vertical polarisation than horizontal polarisation. As you have consulted an aerial installer, I would expect that if this were worth trying that it would have been so.
Basically it means switching the aerial to vertical, so that its elements are up/down rather than flat. The PSB channels (BBC, ITV1, C4, C5 and some others) are at the same strength horizontally and vertically.
The COM channels (Pick TV, ITV3, Film4 etc) are lower power horizontally and the same power as the PSBs vertically. Thus, even without the issue with the trees it is best to use vertical polarisation (for Rowridge). The horizontal polarised signals are more for legacy purposes, i.e. so as to work with existing horizontally-mounted aerials.
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Saturday, 8 December 2012
K
Ken Holt7:17 PM
Why is the signal quality from Emley Moor transmitter so variable? I can be selecting and watching Freeview channels with no problems when for no apparent reason the picture stutters and freezes and I get loud spiking noises on sound. It can sometimes be occasional annoying problems or become completely unwatchable. I am 14 km NNE of the trasmitter and can use internal room arials with great success (although we also have a roof arial). There is no pattern of when the problems occur. The signal quality just fluctuates wildly - is there some technical reason at source why this should be so?
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H
heather7:25 PM
I have had freeview intermittant interference since September---sometimes unwatchable. Have had two visits from the aerial engineer---all normal things checked out, and he tried a couple of things, but the interference is no better. I'm just trying to live with it now but am an OAP and really appreciate resting and watching tv. I never had any problems before September. I love in north Edinburgh. Advice please?
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L
L Peters9:25 PM
We have a Bt set-top box and use freeview most of the time. Postcode SK9 presume Winterhill transmitter. We have been experiencing the pixelation of the picture as well as 'no signal' recovering quickly, I have checked all connections and changed loose cables etc but to no avail. The bt set-top box randomly retunes itself. Not sure what to do now..installation was in June 2012. I am not familiar with tech speak but can you suggest anything else to try.
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Sunday, 9 December 2012
J
jb388:07 AM
heather: When you have already had two visits from an aerial engineer and yet your problem still persists then its not very easy for anyone to offer advice from afar, because nothing beats an on-site investigation, especially where it involves a problem of an intermittent nature that "might" involve something extremely local to your place of residence.
The other point being, that with any query involving reception a post code or one from nearby (e.g: a shop) is required, this to enable access to the reception predictor plus give an idea of the locality as far as the existence of any possible obstructions to the signal is concerned, such as trees etc.
Another aspect being, that living in the North of Edinburgh could involve reception from either Craigkelly or Black Hill, and so this would have to be determined should you not be aware of where you are receiving from, this usually revealed by carrying out a signal check on your TV or box whilst on BBC or ITV and noting the channel number seen associated with the strength / quality indication.
Blackhill: BBC Ch46 - ITV Ch43
Craigkelly: BBC Ch27 - ITV Ch24
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Tuesday, 11 December 2012
V
VALERIE6:45 PM
DAVE
NICHOLAS
Thanks to you both for suggestions. Vertical aerial has been tried but this had no effect. Also signal strength (which was 100%) has been reduced as too much signal strength was thought to be a possible reason. Sadly we are running out of ideas! I do note that certain times of day are much worse, i.e. lunch times and tea times (5-6 p.m.). Could this mean greater switch on at those times? Or might that not have any bearing on it? It can be mighty irritating if you are following a quiz - the picture obliterates when the answers are given!!
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J
jb389:43 PM
VALERIE: If anyone resides in an area where the signal being received falls off at various times of the day (especially in evenings) then this is inclined to point to the signal received being affected by not only atmospheric reasons but to changes in weather conditions (moisture content) affecting the blocking or reflective properties of any vegetation (trees) that may be partially obstructing (or even close to) the signal path from the transmitter to the receiver, this being something that is "very" difficult to find any effective cure for without a great deal of time being spent experimenting with different aerial positions (not necessarily higher) and even then with there being no guarantee that a cure would be found.
Just out of interest, although you have mentioned as having 100% strength at times (although 95% max more preferable) but what does the quality indicate? as problems caused by the aforementioned reasons is usually revealed by the signal indicating high strength at times but accompanied by large fluctuations in the quality, this being a situation that's very seldom ever really cured no matter what might be done as its basically out with local control.
Just another small point, I realise that you have said that your reside in Wimborne, but it would have been of considerable assistance in assessing your situation if you had provided a post code or at least one from nearby, e.g: a shop or a licensed premises etc as this would have enabled access to the reception predictor.
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Thursday, 13 December 2012
M
Mary4:12 PM
My mother lives in Marlborough, Wiltshire, SN8, on the eastern side of town and has intermittent loss of picture and sound. She has a new aerial and a 'booster' to help improve this but, although this has given her some more channels it hasn't improved the quality of her picture or sound. Is there anything else she can do? I live on the other side of town and have no problems, although I do receive my signal from a different transmitter (I have BBC South, she has BBC West)
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M
Michael4:42 PM
Mary: If your mother has the West regional news, then she is picking it up from the Marlborough relay transmitter to the east of the town.
If you are getting the South regional news, that's from the Hannington transmitter, which has all of the Freeview channels - but
the town is on the edge of reception of Hannington (hence why there is a relay transmitter).
I would suggest removing the booster and ensuring the aerial is pointing towards the Marlborough transmitter, and retuning. What kind of signal strength does the TV indicate normally?
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