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please help

mrs_n

Standard Member
Please please help, I would be very grateful if anyone could help with the following. We have a toshiba television with built in freeview, also a toshiba television with built freeview in our kitchen, and two freeview boxes in two of our bedrooms, all has been working well up until two nights ago. Things are fine during the day but at night (about 6ish) the picture on all television's and freeview boxes start picture freezing and making funning buzzing noises for a split second quite frequently. I have read that the problem could be a faulty themostate but I have turned that off and it is still doing it. I have also switch TV on to analogue tv and their is interfernce also in the form of white dotty lines flashing across the screen. We also have a booster ariel which has been causing no problems since we have had it (about a year), and the ariel on the roof seems fine. Aso signal is good from transmitter at Crystal Palace. Please has anyone got any possible answers to what the problem could be.
Many thanks Mrs N.:)
 

radioredcat

Active Member
It's possibly a faulty streetlamp,There has been quite a few cases recently on the forums so it would be advisable to have a look in your street and see if any are out or flashing.


andy
 
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nvingo

Distinguished Member
Yes see if the streetlamps around go on and off at the same time as the interference.
A fault does not necessarily mean that streetlamp will appear to malfunction so it may be difficult to trace, and of course there may be other lamps (private or business security or floodlights) able to cause the same.
If you were of a mind to try and locate it yourself it's suggested that a handheld TV or MW radio and wandering the streets could pinpoint it but probably if there's no obvious candidate is to contact the relevant authority (usually an 0800 number and location identity on a label attached to the post).
 

AndyCob

Well-known Member
If you can pin down that the interference does indeed start at a specific time then it could well be a timed device.

You say you turned off the thermostat, just to make sure you haven't misunderstood something it is unlikely to be the thermostat itself, there is very little power, just a few volts in the thermostat, so that is not likely the source, however the boiler it turns on/off may well be. High current draw devices can cause a spike in your mains loop of your home as they go on and off, many people get pops from TV speakers for example as boilers go on and off, I used to, though not sustained interference, if turning your boiler (rather than just the thermostat off fixes things you might want to get someone to check it for electrical faults). Fridges, freezers etc might also be suspects.

If it is coming up the mains a mains isolator/conditioner might get rid of it (please note an isolator/conditioner is different from a surge protector, though the two devices frequently come combined in one, as part of a multiplug), a surge protector takes out large spikes in voltage that may damage equipment while an isolator/conditioner is meant to smooth the constant much smaller variability out of the mains supply.

As for the street light thing it can happen but I think it has to be one of the big orange sodium arc lamps rather than a halogen or conventional filament bulb, any experts feel free to correct, but I believe as the Sodium arc starts up (it takes as much as 10-15 minutes to warm up and function stabily) the fluctuations put out quite a bit of RF interference.

Of course you may just have a local source of RF interference, any CB radio fans in your immediate area, sub-stations, transformers, high power wireless networks etc?
 

scribbler101

Active Member
"You say you turned off the thermostat, just to make sure you haven't misunderstood something it is unlikely to be the thermostat itself, there is very little power, just a few volts in the thermostat, so that is not likely the source, "

I beg to differ. Thermostats - particulatly the older ones, can spark when switching, and a spark is a very effective radio transmitter.
 

mrs_n

Standard Member
Many thanks, I am going to put the TV's on tonight and see what happens, note the time etc.

Just as an addition to what I wrote last night, the problem stopped at 2.30am this morning. so it has left me even more baffled than ever. :(
 

scribbler101

Active Member
Many thanks, I am going to put the TV's on tonight and see what happens, note the time etc.

Just as an addition to what I wrote last night, the problem stopped at 2.30am this morning. so it has left me even more baffled than ever. :(
Don't some street lights cut off in the early hours to reduce elec consumption?

And central heating ditto.

Sounds like you need another late night to see if it does same every night.

If not solved by end month, interesting to see if it changes with the clocks or not.
 

radioredcat

Active Member
Thermostats carry mains voltage unless it's a recent system as my heating has a wireless thermostat and as scibbler says is an effective radio transmitter.
MRS N i would suggest turning off the central heating completly when the problem occurs to rule it out.


andy
 

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