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

Saorview and Freeview antenna setup

  • 18-11-2013 11:17PM
    #1
    PauloMN
    Moderators, Technology & Internet Moderators, Regional North East Moderators Posts: 10,886 Mod ✭✭✭✭


    In Meath, I've already got a grouped contract antenna pointing towards Clermont Carn for Saorview (no masthead amp). This is distributed to various rooms around the house with a pretty basic distribution amp.

    I'm planning to add a grouped antenna like this for reception of Freeview from Divis. Lots of houses around here have Freeview and I've tested with a pretty poor old wideband antenna which gave me reasonable results. I'm hoping the grouped antenna and a good masthead amp up at the right height will give me pretty reliable results.

    I'm just wondering the best approach for this setup. I think I should have a masthead amp on the Saorview antenna really, the reception is fine but I've noticed breakup from time to time on the new additional channels (RTE+1 for example). This could be the box though (Amiko box) - I've yet to verify that.

    Anyway, I obviously need a masthead for the Freeview antenna - but looking at the different installs on houses near me, I see two boxes on most masts. One is obviously an amp for the Divis antenna, but I'm wondering is the other box an amp for the Clermont Carn antenna, or is it a combiner for both feeds down to one? Hard to tell from any of the ones I've seen.

    Typically how are the feeds combined? At the mast, or down at the distribution amp? If both are combined, can the one power source be used to power two masthead amps (assuming two are used)? If only the Divis antenna has an amp, can they still be combined at the mast?

    It looks like the same standard install is used on any of the houses I've seen with both antennas. If anyone knows what setup is typically used, could you post it for me?

    Finally, I'm going to replace the distribution amp with a better one that will handle Sky remote eyes, as I'm also going to distribute the output from my Sky box to each room (some of which will have a Sky eye). Any recommendations for a decent distribution amp with at least 6 outputs? I'd like to be as well screened as possible (I'm an amateur radio user also) and I'd pay for a decent one.


Comments

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


    The 2 boxes you describe on nearby houses would be an amplifier & a diplexer (combiner with filtered inputs).

    Where the amp is placed would depend on the relative strengths of the signal from each aerial.


  • #3
    PauloMN
    Moderators, Technology & Internet Moderators, Regional North East Moderators Posts: 10,886 Mod ✭✭✭✭PauloMN


    Peter Rhea wrote: »
    The 2 boxes you describe on nearby houses would be an amplifier & a diplexer (combiner with filtered inputs).

    Where the amp is placed would depend on the relative strengths of the signal from each aerial.

    Ok, so it'll either be a wideband amp after the diplexer (amplifying both signals), or it'll be a (possibly) grouped amp just amplifying the Divis aerial and then being fed into a diplexer joining with the Saorview signal I guess...... makes sense. I presume the diplexers handle the supply voltage for the amp then.

    Just need to try and take a closer look at the installs near me so!


  • #4
    zg3409
    Registered Users, Registered Users 2 Posts: 7,345 ✭✭✭zg3409


    If you do not have equipment for peaking the aerial I would recommend paying a professional to install and tweak the setup. The signal strength on TVs is not much use for aligning aerials. In Meath you will still get breakup during high pressure which means it may not work for a few weeks every summer. The normal recommedation is to get the UK channels via satellite.

    You need to figure out the channel numbers (frequencies) of every broadcast (Freeview and Saorview Muxes) and get the correct masthead amplifier and diplexer required. Professionals use special masthead amplifiers designed for certain channels only. In the past fringe electronics made special amplifiers for different parts of Ireland to maximise gain on wanted channels and block local sources.

    General info here (but might be a little out of date)
    http://www.tvtrade.ie/how-to-combine-saorview-and-freeview-on-the-same-digital-receiver.html

    This gives an idea of what is required:
    http://www.fringeelectronics.co.uk/PDF/Masthead.pdf

    Block local signals is even more important nowadays as Tetra Garda radio is around 400Mhz and strong in most towns and new 4G mobile phone is in the 700Mhz range. 4G is not available in Meath, but could be switched on any month now.

    According to here:
    http://www.ukfree.tv/txdetail.php?a=IJ287750

    Divis uses:
    CH27 522Mhz
    CH21 474Mhz
    CH24 498Mhz
    CH26 514Mhz
    CH29 538Mhz
    Horizontal

    Clairmont Cairn is on
    Ch52
    Ch56
    Vertical

    You would also need to check for other local transmitters which might cause problems.

    So you would want a group A Antenna and Group A specialised high gain masthead amplifier. Ideally the amplifier should have a tetra and 4G filters but group A specialised will probably block out anything above or below anyway. Gain possibly should be 28dB.

    A diplexer like this is needed:
    http://www.tvtrade.ie/triax-uhf-diplexer-tfc-3537.html

    Ideally you would get one that will allow power through to the mast head amplifier and not to the non amplified Saorview aerial.

    The more you split the signal the less likely it is to be reliable. I would suggest having a way of removing some of the splits when reception is dodgy so you can improve reception on the main TV. Even with the best setup during periods of high pressure you will probably pick up multiple transmitters on the same frequency meaning reception will be impossible.

    If you want Sky eyes, there are loads of distribution amps Sky eye compatable. Just beware with a Sky eye you do not get a high defintion picture meaning it will be grainy on large TVs.

    The setup would be

    NI Group A connected to dedicated masthead amp
    Personally I would run a seperate cable inside for each aerial and have the power supply and diplexer in the attic. In this way you can bypass the diplexer if the signal is dodgy.

    If using an amplifier for Saorview, you need to make sure it will not amplify group A, or it could make problems by picking up other transmitters in other directions. I would recommend a non amplified aerial if possible.

    A diplexer with correct channelised inputs is used to combine the two aerials before feeding to the distribution amplifiers. Some can allow power pass through, and ideally you would use one that allows power to pass on one leg to the NI masthead amplifier. If the diplexer is inside the attic the power unit for the amplifier can be mounted between the diplexer and the masthead amplifier. The you can use any diplexer without worrying about it passing power or not.

    After the power supply it needs to go to the RFIN of the Sky box, and then the RF2 of the Sky box goes to the distribution amplifier and on to each TV with a Sky eye blocking the Sky eye power from the TV.


Advertisement