Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

Understanding UHF aerial setup

  • 11-01-2018 7:52pm
    #1
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭


    Hi,

    I am a bit confused regarding the setup of a relative’s UHF aerial.

    Current setup:
    Mounted in attic to timber rafter
    Location: Laois
    Pointed South Easterly

    I couldn’t tune any Saorview channels by running an auto scan. Thankfully they had another working set top box that was receiving Saorview. I checked the configuration and found it set to UHF channels 44 & 47. This is transmitted from Cairn Hill in Longford!

    I entered these channels and it worked!

    It doesn’t find any signal on channels 23 & 26 (Mount Leinster), despite it being much closer and the antenna being pointed toward it.

    What is going on here?


Comments

  • #2
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    GerryDerpy wrote: »
    ... What is going on here?

    It's actually pointed northwest? If it's the type that looks like an arrow, with the v-shaped reflector, the 'pointy' end is away from the v.


  • #3
    The Cush
    Registered Users, Registered Users 2 Posts: 15,852 ✭✭✭✭The Cush


    Which transmitter does the Saorview coverage checker recommend for for the house location

    https://www.saorview.ie/en/get/coverage


  • #4
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    Thurston? wrote: »
    It's actually pointed northwest? If it's the type that looks like an arrow, with the v-shaped reflector, the 'pointy' end is away from the v.

    Yep it is an arrow shape. The v is pointing North West, the “long” bit pointing South East.


  • #5
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    The Cush wrote: »
    Which transmitter does the Saorview coverage checker recommend for for the house location

    https://www.saorview.ie/en/get/coverage

    Kilduff, which is channels 52 & 56. These don’t work either.


  • #6
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    I assume it's not just like someone's gone & stuck something in front of it, blocking the signal?


  • Advertisement
  • #7
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    Thurston? wrote: »
    I assume it's not just like someone's gone & stuck something in front of it, blocking the signal?

    Nope, I checked the aerial for damage, checked coaxial cables and connections, look good.

    How it manages to pickup Cairn Hill is what is troubling me.


  • #8
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    Cairn Hill is a powerful transmitter, so I wouldn't be surprised at it being picked up like that.

    Why the aerial is pointed at Mt. Leinster can probably only be answered by whoever installed it.

    If it seems a case that the installer hadn't a clue what they were at, I'd just try it on Cairn Hill or Kilduff, & see which comes in best.


  • #9
    The Cush
    Registered Users, Registered Users 2 Posts: 15,852 ✭✭✭✭The Cush


    GerryDerpy wrote: »
    I couldn’t tune any Saorview channels by running an auto scan. Thankfully they had another working set top box that was receiving Saorview. I checked the configuration and found it set to UHF channels 44 & 47. This is transmitted from Cairn Hill in Longford!

    I entered these channels and it worked!

    It doesn’t find any signal on channels 23 & 26 (Mount Leinster), despite it being much closer and the antenna being pointed toward it.

    What is going on here?
    GerryDerpy wrote: »
    How it manages to pickup Cairn Hill is what is troubling me.

    A quirk of your location combined with aerial mounted in the attic resulting in a weaker received signal maybe?

    Do you know what grouped aerial is being used?


  • #10
    The Cush
    Registered Users, Registered Users 2 Posts: 15,852 ✭✭✭✭The Cush


    Thurston? wrote: »
    Cairn Hill is a powerful transmitter, so I wouldn't be surprised at it being picked up like that.

    Why the aerial is pointed at Mt. Leinster can probably only be answered by whoever installed it.

    If it seems a case that the installer hadn't a clue what they were at, I'd just try it on Cairn Hill or Kilduff, & see which comes in best.

    Maybe the original aerial was for VHF Mt. Leinster in the day and simply continued for the transition to UHF analogue and DTT. The recommended transmitter is Kilduff now which wasn't around until a few years ago.


  • #11
    coylemj
    Registered Users, Registered Users 2 Posts: 25,622 ✭✭✭✭coylemj


    Relative of mine gets a perfectly good Saorview signal in Nth. Co. Laois from Mt. Leinster.


  • Advertisement
  • #12
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    Thurston? wrote: »
    Cairn Hill is a powerful transmitter, so I wouldn't be surprised at it being picked up like that.

    Why the aerial is pointed at Mt. Leinster can probably only be answered by whoever installed it.

    If it seems a case that the installer hadn't a clue what they were at, I'd just try it on Cairn Hill or Kilduff, & see which comes in best.

    I actually thought it made sense to go for Mount Leinster, as Kilduff wouldn’t have existed at the time of installation, why woukd you think otherwise?


  • #13
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    The Cush wrote: »
    A quirk of your location combined with aerial mounted in the attic resulting in a weaker received signal maybe?

    Do you know what grouped aerial is being used?

    I don’t know what group the aerial is, but don’t think that affects the frequencies in question.


  • #14
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    GerryDerpy wrote: »
    I actually thought it made sense to go for Mount Leinster, as Kilduff wouldn’t have existed at the time of installation, why woukd you think otherwise?

    Some local obstruction, like a hill or trees? I'm only going by what you posted i.e. you seem to be getting a better Cairn Hill signal from behind the aerial than you're getting for Mt. L. where it's actually aligned.

    It must have provided satisfactory reception from Mt. L. at some point then?


  • #15
    FishOnABike
    Registered Users, Registered Users 2 Posts: 4,636 ✭✭✭FishOnABike


    GerryDerpy wrote: »
    I don’t know what group the aerial is, but don’t think that affects the frequencies in question.
    Mount Leinster, channels 23 and 26 are group A
    Cairn Hill, channels 44 and 47 are group B

    If your aerial is group A the signal from Mount Leinster would be significantly attenuated, by between 9 and 15 dB. Could a side lobe from a group B aerial be picking up the signal from Cairn Hill, channels 44 and 47?


  • #16
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    Thurston? wrote: »
    Some local obstruction, like a hill or trees? I'm only going by what you posted i.e. you seem to be getting a better Cairn Hill signal from behind the aerial than you're getting for Mt. L. where it's actually aligned.

    It must have provided satisfactory reception from Mt. L. at some point then?

    Well the guy that installed it also set up the old box that was configured to the Cairn Hill channels. So it never picked up Mt Leinster. But he might not have intended to go for Cairn Hill, as performing an auto scan sets the channels to that of Cairn Hill.


  • #17
    GerryDerpy
    Closed Accounts Posts: 761 ✭✭✭GerryDerpy


    FishOnABike wrote: »
    Mount Leinster, channels 23 and 26 are group A
    Cairn Hill, channels 44 and 47 are group B

    If your aerial is group A the signal from Mount Leinster would be significantly attenuated, by between 9 and 15 dB. Could a side lobe from a group B aerial be picking up the signal from Cairn Hill, channels 44 and 47?

    I misunderstood the impact of the groups so. I thought they were all about removing noise from the upper 4g range.

    I will climb up to the attic and check.


  • #18
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    FishOnABike wrote: »
    ... If your aerial is group A the signal from Mount Leinster would be significantly attenuated, by between 9 and 15 dB.

    You mean if the aerial is group B?

    The signal wouldn't be attenuated, unless you mean relative to a group A aerial, & even then it wouldn't be anything like 9 - 15 dB.
    GerryDerpy wrote: »
    Well the guy that installed it also set up the old box that was configured to the Cairn Hill channels. So it never picked up Mt Leinster. But he might not have intended to go for Cairn Hill ...

    Doesn't exactly sound like the most competent installer, if that's the way things were when he left it.


  • #19
    FishOnABike
    Registered Users, Registered Users 2 Posts: 4,636 ✭✭✭FishOnABike


    Thurston? wrote: »
    FishOnABike wrote: »
    ... If your aerial is group A the signal from Mount Leinster would be significantly attenuated, by between 9 and 15 dB.

    You mean if the aerial is group B?

    The signal wouldn't be attenuated, unless you mean relative to a group A aerial, & even then it wouldn't be anything like 9 - 15 dB.
    GerryDerpy wrote: »
    Well the guy that installed it also set up the old box that was configured to the Cairn Hill channels. So it never picked up Mt Leinster. But he might not have intended to go for Cairn Hill ...

    Doesn't exactly sound like the most competent installer, if that's the way things were when he left it.
    Yes, meant group B, replying when I was half asleep.

    As you say a group B aerial would attenuate the signal from Mount Leinster (CH 22 and 26 are in the band for a group A aerial)

    I was using the figures from table A5-1 on https://ukfree.tv/article/1107051549/Aerial_groups_new_feature_ From that a group B aerial would significantly attenuate the lower end of group A frequencies.


  • #20
    Thurston?
    Closed Accounts Posts: 2,278 ✭✭✭Thurston?


    FishOnABike wrote: »
    ... I was using the figures from table A5-1 on https://ukfree.tv/article/1107051549/Aerial_groups_new_feature_ From that a group B aerial would significantly attenuate the lower end of group A frequencies.

    I could be wrong, but I'd be surprised if there are aerials out there that actually perform like that.


  • #21
    NealXu
    Registered Users, Registered Users 2 Posts: 1 ✭NealXu


    Hi...as per my knowledge if you gets reception at home try tuning in the Plaza box on his home aerial. Then take it to where you are planning to use it. Dial up a COM7 or 8 channel and see if you can tweak the aerial a bit to improve reception at all. RF can be a funny beast and you might find simply moving it forwards


  • Advertisement
Advertisement