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?
Thursday, 10 June 2021
C
Chris.SE1:21 PM
read more:
Must be a problem at your end.
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J
jack8:01 PM
For the last couple of weeks we have been having regular (every minute or so) breakups
from sutton com7 channels. All others seem ok.
Com7 however is showing about 30% signal recieved compared to all others.
Is sutton having problems? We have 2 set top boxes all with the same issue - but
both are fed from the same rooftop aerial through a distribution amp. This setup has been
working fine for about 2 years.
Or could there be something wrong my end - I have tried swapping cables (except the main run
to the roof) I did try removing 1 box from the amplifier as someone said a fault on that
could cause interference but no luck (and I expect it would be more than just com7 ?)
Any info welcome. thanks
Posted thurs june 10 2021 at 21:00
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Friday, 11 June 2021
C
Chris.SE4:01 AM
jack:
As you haven't given a full postcode, we don't know if you are referring to reception from Crystal Palace in the Sutton area of London (the Sutton Relay transmitter doesn't have COM7), or whether you mean the Sutton Coldfield transmitter.
Whichever, none of those transmitters are currently listed for Planned Engineering or have any Faults listed that I can find.
Have you changed anything around in your installation when this started?
Make sure you don't have any HDMI leads near unscreened/poorly screened flyleads/aerial leads (ie. not double screened) as HDMI has been known to cause interference, especially to UHF C55 - COM7.
I take it you've checked your aerial and downlead looks intact/undamaged and the aerial still points in the correct direction.
You say it's 30% signal, what is it on the other multiplexes, and what are the Quality (or Error) figures like?
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J
jack11:14 AM
Hi chris - thanks for the post
Sorry yes its sutton coldfield we are in birmingham
Yes I did a visual check on the aerial and cable - it seems the same as always.
We havn't changed anything - it just started happening - I ignored it for over a week
assuming maintenance or something but the listings links from here say not and no
faults reported elsewhere by others I can find either.
The values on all othe channels are around 76-81% power at 100% quality fairly stable
Except now Ch48 on 69000Khz is bouncing around between 28% and55% with 100%quality
(That is normally about 55% solid so something has changed there too in the last day)
Ch26 (now unused I think) on 5140000Khz is at 20%power 100% quality fairly stable
The channels on com7 (Ch55 7460000Khz) eg. have now increased power slightly and are bouncing
around between 38 and about 62 with constant 100% quality but breakups still prevalent.
I'll check the HDMI cable issue - thanks for that tip.
I'll check power lead routing is away from the input too.
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Saturday, 12 June 2021
C
Chris.SE7:21 AM
jack:
If you haven't changed anything and checked all your coax plugs, connections, flyleads and swapped leads etc., have you introduced any new electrical equipment of any type, including lighting?
Do the problems occur at any particular time of day?
I assume that's the Local multiplex you are getting on C48. As for C26, that's not transmitted from Sutton Coldfield, but three other nearby transmitters use it for the BBCA multiplex (as a SFN) - Bromsgrove, Lark Hill & The Wrekin. Without a full postcode, I can't say if you might normally receive any of those, but the current high pressure is causing some periodic and variable tropospheric ducting which is bringing in signals from more distant transmitters. This might cause some interfering signals to affect C48.
But as your initial problem was COM7, as it's a SFN, problems/engineering at other nearby main transmitters with COM7 might have an effect on your reception. Which direction your aerial is pointing might give a clue. Having had a bit of a dig around I've also spotted that Sutton Coldfield was on Planned Engineering for the whole of May!
There were some intervals of tropo over some days in recent weeks as well, just to complicate matters, but that doesn't mean it affected your reception, that's so difficult to predict as it can affect different parts of the country by varying degrees and signals can change by the second or remain stable for much longer periods.
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Monday, 14 June 2021
J
jack4:04 PM
Hi chris
Many thanks for the very detailed response again.
Com7 power seems to have increased (I can't quantify at the moment as I have scheduled recording running)
but think its up maybe 20% of it's previous. Breakups not seen today but previously was not
time sensitive.
Oddly enough I've been recording smallville on paramount (ch32 - Ch42 642000Khz) at around
3 am. for the last week and that has been breaking up too although that chanel seems fine during
the day
Its very weird. I'll have to just keep my eyes open and see how it goes I guess.
Thanks again - if anything majour happens or I spot anything generally useful I'll put up a post.
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Tuesday, 15 June 2021
C
Chris.SE1:13 AM
jack:
Thanks for the update, keep us posted of anything significant.
The only thing I can add to my comment about COM7 SFN and Planned Engineering at other near main transmitters is that Ridge Hill had Planned Engineering last week with "Possible weak signal" and now Oxford and Waltham are similarly listed this week. Theoretically I guess it could have some impact on your COM7 signal.
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Wednesday, 7 July 2021
K
Kevin Dixon11:46 AM
Hello,
Intermittent interference, pixellated picture, freezing, audio interruption,
occasionally loss of signal message on Emley Moor transmitter here on South edge of York.
Usually during summer days, most noticeable over last week, sometimes
with signal strength indicated as high. Bad during rain.
Noticeable in past years during local Harvest time.
Even worse when my PVR is switched on and the TV antenna is routed via it.
I do not have any other electrical equipment near the TV inclusive of Mobile/Radio.
Have manually retuned, replaced TV antenna and cable.
Have switched off PVR and connected TV antenna direct to TV, still experiencing problems.
There are trees between myself and Emley Moor so have also tried alternative transmitters to the
North, West and South East but I still get interference especially Freeview ch 14, 25, 4, 15
sometimes 1 and 2.
Other people in my village experience TV reception problems and a look at all the TV antennae
show them all pointing at different masts.
I am now considering a FreeSat solution but asking you here if you have any other suggestions.
Could someone be using an illegal radio or have a TV signal booster or is it
4G interference (no mast nearby) or EMI from next door and how can I check or is it just simpler
to go to FreeSat ?
Thanks,
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Thursday, 15 July 2021
C
Chris.SE5:48 AM
Kevin Dixon:
There has been engineering work at Emley (and also a number of local relay transmitters). The work at Emley (as I undertstand it) has been to get the main mast fully in service.
There's been some periodic adverse weather conditions affecting reception for some, which may not have helped. If your reception doesn't settle down then Freesat may be your best option.
How far away roughly are the trees?
Amateur or other such radio transmissions are unlikely to be affecting you (similarly 4/5G) unless there are antennae or masts close to you which I'm sure you'd notice.
We'd need a full postcode to look at predicted reception in your locale, which sounds like an awkward area if your neighbours have similar problems.
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Tuesday, 20 July 2021
Thanks for sharing the great content here, i will read the other interesting pagess. Yeah, hope we could view more video here.
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