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Interference issue on TV and radio

  • 04-03-2020 9:38pm
    #1
    ka2
    Closed Accounts Posts: 105 ✭✭


    I'm having a strange issue with interference on my TV and radio setup which I thought was resolved but more on that later.

    I have a contract group A aerial and an FM dipole installed. I initially had the UHF aerial pointing vertically at the new Drogheda relay but noticed intermittent breakup every few minutes despite a very strong signal. Assuming that the signal was too strong, I realigned the aerial horizontally towards Kippure which is still coming in well. No breakups since, so I assumed it was OK.

    But now I realised the radio is also affected. It just causes random bursts of static on an otherwise clear signal. It's not on any specific station, I know for sure that RTÉ Radio 1, Classic Hits and East Coast FM are all affected (so probably anything really).

    I've since noticed that the TV detects a BER increase on Kippure but not enough to cause breakup, hence why I initially thought the issue was solved. Maybe the polarisation change is making it less susceptible?

    I've attached a lossless audio clip from RTÉ Radio 1 on 87.8 from Clermont Carn (so I don't trigger any copyright police!) where the interference is present. It's crystal clear otherwise. Would anyone have any idea what could be causing this? I tried bypassing the distribution amp and going straight in to the TV and radio but it didn't make any difference.


Comments

  • #2
    dxhound2005
    Registered Users, Registered Users 2 Posts: 21,401 ✭✭✭✭dxhound2005


    Something very local, probably in your own house. Not anything coming from the transmitter. You could prove that by listening on a portable or the car radio 100 yards away. Not what would be called static in the sense of what happens on medium wave.

    https://www.radioandtvhelp.co.uk/help-guides/radio/troubleshooting-interference-to-fm-radio


  • #3
    Winston Spencer
    Registered Users Posts: 28 ✭Winston Spencer


    I've had bother in the past with a cooker thermostat.


  • #4
    icdg
    Moderators, Technology & Internet Moderators Posts: 11,860 Mod ✭✭✭✭icdg


    moved to terrestrial


  • #5
    ka2
    Closed Accounts Posts: 105 ✭✭ka2


    Thanks guys. Just a quick update on this one. I know it's not coming from the transmitter because everything is affected. I also have a very low power hobby analogue SDR TV transmitter that shows white spots on the screen when it happens.

    I'm thinking it might be something outside the house because if I turn on the car radio and wait outside I'll hear in the car too. (I don't hear it when driving around of course.) I've also tried to cut off as much power as possible in the house - I think at one stage I unplugged everything that could be unplugged - and it was still there. I may just have to live with it.


  • #6
    Ger Roe
    Registered Users, Registered Users 2 Posts: 2,145 ✭✭✭Ger Roe


    ka2 wrote: »
    Thanks guys. Just a quick update on this one. I know it's not coming from the transmitter because everything is affected. I also have a very low power hobby analogue SDR TV transmitter that shows white spots on the screen when it happens.

    I'm thinking it might be something outside the house because if I turn on the car radio and wait outside I'll hear in the car too. (I don't hear it when driving around of course.) I've also tried to cut off as much power as possible in the house - I think at one stage I unplugged everything that could be unplugged - and it was still there. I may just have to live with it.

    Can you use the car, or walk about with a portable radio to try and plot the range distance of the interference?. It might be a help in locating the source.


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  • #7
    Gonzo
    Moderators, Science, Health & Environment Moderators Posts: 16,966 Mod ✭✭✭✭Gonzo


    my Saorview and FreeView hasn't worked for 2 weeks now. I've tried retuning everything and still no Freeview. Saorview is an unwatchable pixilated mess with no sound. Our Tv in the kitchen depends on that digital signal from the aerial so no picture for the past 2 weeks at least. We do have Sky in the living room so that's our only tv where we can watch tv.


  • #8
    ka2
    Closed Accounts Posts: 105 ✭✭ka2


    Gonzo wrote: »
    my Saorview and FreeView hasn't worked for 2 weeks now. I've tried retuning everything and still no Freeview. Saorview is an unwatchable pixilated mess with no sound. Our Tv in the kitchen depends on that digital signal from the aerial so no picture for the past 2 weeks at least. We do have Sky in the living room so that's our only tv where we can watch tv.
    Your issue might be related to the Saorview frequency changes recently. The timeline would add up to that. Where are you situated?

    For me, it seems I'm dealing with something outside the house that's generating random bursts of interference. Over the weekend I shut off all power at the main switch and tuned into Radio 1 on 252 on a battery powered radio. Within a few minutes I heard a buzzing over the LW signal for about a second or two. So it's definitely not in the house.


  • #9
    Gonzo
    Moderators, Science, Health & Environment Moderators Posts: 16,966 Mod ✭✭✭✭Gonzo


    ka2 wrote: »
    Your issue might be related to the Saorview frequency changes recently. The timeline would add up to that. Where are you situated?

    For me, it seems I'm dealing with something outside the house that's generating random bursts of interference. Over the weekend I shut off all power at the main switch and tuned into Radio 1 on 252 on a battery powered radio. Within a few minutes I heard a buzzing over the LW signal for about a second or two. So it's definitely not in the house.

    I presumed it's related to the weather/high pressure. I'm located near Dunshaughlin. I normally get a half decent FreeView UK signal and perfect Saorview signal. Both services are gone, FreeView is completely gone and Saorview is as good as gone too, just a screen of garbled pixels, green and pink squares and no audio. I've rescanned everything twice and it finds very little if any signal.


  • #10
    Elvis Hammond
    Registered Users, Registered Users 2 Posts: 491 ✭✭Elvis Hammond


    Gonzo wrote: »
    I presumed it's related to the weather/high pressure. I'm located near Dunshaughlin. I normally get a half decent FreeView UK signal and perfect Saorview signal. Both services are gone, FreeView is completely gone and Saorview is as good as gone too, just a screen of garbled pixels, green and pink squares and no audio. I've rescanned everything twice and it finds very little if any signal.

    Did you check the UHF channel nos./frequencies of these poor signals?


  • #11
    Alun
    Registered Users, Registered Users 2 Posts: 21,487 ✭✭✭✭Alun


    Ger Roe wrote: »
    Can you use the car, or walk about with a portable radio to try and plot the range distance of the interference?. It might be a help in locating the source.
    Not TV related, but some years ago I was having terrible problems with dropouts on my eircom ADSL connection. I used an AM radio to confirm it was due to some very strong external interference, and after a lot of persuading got Comreg involved.

    It took a while, and a couple of visits, as the interference wasn't always there, but eventually they tracked it down to a distant neighbour who was doing something he shouldn't have been (they declined to tell me exactly what!) Anyway, whatever he was doing, the interference was being transmitted along the electricity supply lines which ran down the ducting in the pavement outside the houses, which also housed the eircom cabling.

    Never had a problem since then.

    So, OP, if you're convinced it is external interference, I'd suggest getting them involved if you can. It helps if you can give them as much technical information as possible including the peak frequency of the suspected interference.


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  • #12
    Antenna
    Registered Users, Registered Users 2 Posts: 2,331 ✭✭✭Antenna


    ka2 wrote: »
    For me, it seems I'm dealing with something outside the house that's generating random bursts of interference. Over the weekend I shut off all power at the main switch and tuned into Radio 1 on 252 on a battery powered radio. Within a few minutes I heard a buzzing over the LW signal for about a second or two. So it's definitely not in the house.

    Is it definitely the same interference?

    If it is affecting LW to VHF/UHF I would expect its very close.

    You have tried shutting off mains power, but anything on a UPS, burglar alarm or anything else with battery backup it could be ??

    DO you have immediate neighbours?

    How often might it happen and is it liable to happen any time of day or between particular hours (i.e. when neighbours might have central heating on) ?


  • #13
    ka2
    Closed Accounts Posts: 105 ✭✭ka2


    I don't like picking apart posts like this as it can come across as nasty but that's not my intention at all here. :)
    Antenna wrote: »
    Is it definitely the same interference?
    I'm pretty sure it is. It has a distinctive pattern to it. It's a very brief blip of noise, followed by a longer piece of noise for anything up to two seconds. That's what I've heard on both radios. On one occasion I left the LW radio on and had a TV on at the same time. When I heard the buzz, I saw breakup on the TV shortly after.
    Antenna wrote: »
    You have tried shutting off mains power, but anything on a UPS, burglar alarm or anything else with battery backup it could be ??
    I never thought of the alarm but I'd be too afraid to mess with it as I know nothing about them. I did have to disarm it when I cut the power so it's definitely on some form of UPS. Food for thought!
    Antenna wrote: »
    DO you have immediate neighbours?
    Yes, I'm mid-terrace so have neighbours on both sides.
    Antenna wrote: »
    How often might it happen and is it liable to happen any time of day or between particular hours (i.e. when neighbours might have central heating on) ?
    I haven't worked out if it's a consistent pattern or not but that was something I've been planning to do at some point.


  • #14
    dxhound2005
    Registered Users, Registered Users 2 Posts: 21,401 ✭✭✭✭dxhound2005


    I listened to the clip of the noise again. To me this description in the link I put in post #2 seems to be worth investigation.

    Loud rasping sound
    This effect happens in bursts of a few seconds at a time and is due to central heating thermostats. Switching off the heating system while you are experiencing the problem will help to identify it. If the problem stops you may have to repair or replace the thermostat. If not, it could be a nearby neighbour's thermostat. It’s worth checking with them.


  • #15
    ka2
    Closed Accounts Posts: 105 ✭✭ka2


    OK, so I've measured this last night and this morning with a timer. It's every 5 and a half minutes. Seems like an unusual number.

    I have been thinking about the alarm but would be way too afraid to go near it. I don't know much about them but do know that they have tamper mechanisms. Then again, as mentioned above, could be a neighbour's thermostat too.

    Thanks for the advice so far, much appreciated.


  • #16
    Antenna
    Registered Users, Registered Users 2 Posts: 2,331 ✭✭✭Antenna


    If its a constant interval of 5 and a half minutes it wouldn't be a thermostat (and also rules out other possibilities ).

    And its happening 24 hours a day ??
    If you are unsure leave something recording an affected station/frequency all night long and analyse the recording the following day to confirm.

    If you think it might be the alarm -
    Watch the alarm control unit until the interference happens and see if any change happens on it when it happens (such as an indicator LED blinking on of off?)


  • #17
    ka2
    Closed Accounts Posts: 105 ✭✭ka2


    I'm not so sure it's 24 hours a day. It is happening at the usual 5:30 intervals at the moment though. I have some time this morning so will check the alarm.

    When I installed this system I reused the existing cabling in the house, which is RG6. Would it be worth replacing it with WF100 to take advantage of the extra shielding? I guess I'm trying to look at what I can do with my own setup before I go looking outside.


  • #18
    Antenna
    Registered Users, Registered Users 2 Posts: 2,331 ✭✭✭Antenna


    ka2 wrote: »
    When I installed this system I reused the existing cabling in the house, which is RG6. Would it be worth replacing it with WF100 to take advantage of the extra shielding? I guess I'm trying to look at what I can do with my own setup before I go looking outside.


    If the interference is being picked up by the aerial, replacing the cable is not going to resolve the issue.

    If the interference source is within your house and close to the cable, it could be of help. If you have a wall socket and flylead to your receiver, these are much more likely to be responsible for letting in very nearby interference (than RG6 cable) as are often poor quality.

    The best thing is try and identify the source before deciding what to do


  • #19
    ka2
    Closed Accounts Posts: 105 ✭✭ka2


    Just a little update on this one. The issue persists but I think I've managed to find a workaround at least for the TV side of things.

    I can see the neighbour's gas exhaust is upstairs at the front of the house on the opposite side of our bedroom wall. The bedroom is where the noise seems to be the strongest so it makes me suspect the neighbour's central heating even more. I found that if I turned the aerial to face the back wall of the house, the aerial seems to be somewhat shielded from the noise as I don't get any breakup. By doing so, the aerial is not pointing at anything in particular but it's still getting an excellent signal from both Drogheda Mux 1 and Clermont Carn Mux 2 (despite being out of group for the latter).

    Not sure how I could go about asking them to check their timer!


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