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Issues receiving COM6 mux on ch 49 in Greenhill, Letterkenny

  • 30-10-2012 10:02pm
    #1
    byrnefm
    Registered Users, Registered Users 2 Posts: 892 ✭✭✭


    Hi,

    A friend of mine in Greenhill, Letterkenny is picking up all six Muxes on Freeview but noticed that the mux with FilmFour and Yesterday on UHF ch 49 is breaking up a fair bit - but all the other muxes come in without issue.

    He was also able to pick up five of the six before ASO (Letterkenny Saorview blocking the sixth).

    We were trying to figure out what might be making the mux on UHF ch 49 break up a lot - the only channel I can see that is also on ch 49 within any distance is in Clonmany but seems to be too far away to cause interference.

    Would anyone know if there are any other DTT channels on ch 49 that could be interfering?

    He did mention that he has just a grid type aerial and I suggested that a Yagi may help but I wanted to check if there's something else we're not thinking of?


Comments

  • #2
    Peter Rhea
    Banned (with Prison Access) Posts: 4,285 ✭✭✭Peter Rhea


    Presumably he's also receiving Saorview? From Letterkenny or Hollywell Hill? Does he only have 1 aerial or is there a diplexer in the system?


  • #3
    sesswhat
    Registered Users, Registered Users 2 Posts: 1,177 ✭✭✭sesswhat


    Near Ballybofey, I did have a problem with Castlederg coming in on the side of the Limavady aerial, although it's a lot closer to me. Is there an unshielded mast-head amp on the pole?

    Any sky boxes in the system?


  • #4
    Peter Rhea
    Banned (with Prison Access) Posts: 4,285 ✭✭✭Peter Rhea


    The distance & the intervening terrain would take care of any interference from Castlederg.


  • #5
    excollier
    Closed Accounts Posts: 1,576 ✭✭✭excollier


    I was getting perfect reception of the HD channels (BBCB Mux ch 55) from Limavady until last night. Gone now.
    Always had trouble with Limavady, from DSO it had been perfect on all channels. The rest are fine though.


  • #6
    byrnefm
    Registered Users, Registered Users 2 Posts: 892 ✭✭✭byrnefm


    Peter Rhea wrote: »
    Presumably he's also receiving Saorview? From Letterkenny or Hollywell Hill? Does he only have 1 aerial or is there a diplexer in the system?
    He has just the one (grid) aerial and is picking up Saorview from (I believe) Holywell Hill.


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  • #7
    byrnefm
    Registered Users, Registered Users 2 Posts: 892 ✭✭✭byrnefm


    sesswhat wrote: »
    Near Ballybofey, I did have a problem with Castlederg coming in on the side of the Limavady aerial, although it's a lot closer to me. Is there an unshielded mast-head amp on the pole?

    Any sky boxes in the system?

    He has a mast-head amp but I don't know if it's unshielded or not. Wrt Sky - I'll check with him tomorrow.


  • #8
    lawhec
    Closed Accounts Posts: 1,757 ✭✭✭lawhec


    Peter Rhea wrote: »
    The distance & the intervening terrain would take care of any interference from Castlederg.
    Not to mention that the TX aerials aren't pointing towards Ballybofey (more to Castlefinn) and that the max ERP is just over 2W per mux with opposite polarity to the SDN & Arqiva muxs from Limavady.

    WRT the problem in the OP, Clonmany is vertically polarised with just 20W max ERP which is probably not directed towards Letterkenny. If it were that his aerial had clear LOS to Clonmany then I'd say in theory it might cause a problem, but I'd suspect that's not it.


  • #9
    sesswhat
    Registered Users, Registered Users 2 Posts: 1,177 ✭✭✭sesswhat


    Peter Rhea wrote: »
    The distance & the intervening terrain would take care of any interference from Castlederg.
    lawhec wrote: »
    Not to mention that the TX aerials aren't pointing towards Ballybofey (more to Castlefinn) and that the max ERP is just over 2W per mux with opposite polarity to the SDN & Arqiva muxs from Limavady.

    Knowing Castlederg's ERP, no-one was more surprised than me. However, for the first couple of days after switchover, I could not tune in to C58 from Limavady. Experimenting with an indoor aerial, I was able to pick up a strong vertical signal on C58 from the direction of Castlederg. I had never had a sniff of a signal from this transmitter before, which is understandable considering the terrain and the low power. When I tried the same thing last night nothing registered at all.

    Could it be that the transmitter was operating initially with the wrong (much higher) ERP?


  • #10
    Peter Rhea
    Banned (with Prison Access) Posts: 4,285 ✭✭✭Peter Rhea


    sesswhat wrote: »
    Peter Rhea wrote: »
    The distance & the intervening terrain would take care of any interference from Castlederg.
    Knowing Castlederg's ERP, no-one was more surprised than me. . .

    I was actually referring to the OP's situation when I posted that, I just took your word for it wrt your own interference problem & didn't check, but same applies to Ballybofey, along with the tx factors mentioned by Lawhec.


  • #11
    sesswhat
    Registered Users, Registered Users 2 Posts: 1,177 ✭✭✭sesswhat


    Peter Rhea wrote: »
    I was actually referring to the OP's situation when I posted that, I just took your word for it wrt your own interference problem & didn't check, but same applies to Ballybofey, along with the tx factors mentioned by Lawhec.

    I agree. It should be impossible. The rogue signal on the indoor aerial is hard to explain but as it's gone now I'll probably never know where it came from.

    Getting back to the OP this is the profile for Clonmany to Greenhill so I think that rules that out.


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  • #12
    Peter Rhea
    Banned (with Prison Access) Posts: 4,285 ✭✭✭Peter Rhea


    byrnefm wrote: »
    He has just the one (grid) aerial and is picking up Saorview from (I believe) Holywell Hill.

    He's probably marginal on all muxes & Arq. B on ch.49 just happens to be a bit weaker.
    sesswhat wrote: »
    The rogue signal on the indoor aerial is hard to explain but as it's gone now I'll probably never know where it came from.

    With the aerial being indoors, it could have been a reflection of the Limavady signal that had managed to become cross polarised.


  • #13
    byrnefm
    Registered Users, Registered Users 2 Posts: 892 ✭✭✭byrnefm


    Peter Rhea wrote: »
    He's probably marginal on all muxes & Arq. B on ch.49 just happens to be a bit weaker.
    Thanks for all your replies.

    It's possible alright, regarding the signal. I asked him what his signal strength was like on the TV, according to its own meter. It gave 80/100 for the BBC mux and 10/100 for the COM6 mux. He's going to try out a TV signal booster over the weekend to see if it gives a more stable picture on COM6 (which he said is usually unwatchable, apart from last night).


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