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DTT transmitter strength...?

  • 21-07-2010 2:35pm
    #1
    tmcw
    Closed Accounts Posts: 396 ✭✭


    I was just wondering if the current trials are at the expected strength that they'll be when the service is finally launched, or will there be a procedure similar to the UK where it will be increased after analogue is switched off?


Comments

  • #2
    Apogee
    Registered Users, Registered Users 2 Posts: 3,878 ✭✭✭Apogee


    4814947047_aa11526db8_b.jpg
    4815569752_5ec1a4214f_b.jpg

    4743454690_37d3049a3e_b.jpg


  • #3
    watty
    Registered Users, Registered Users 2 Posts: 32,445 ✭✭✭✭watty


    I revise my estimate of 2% to 7% needing Saorsat up
    Now 8% to 12% :)

    They are unlikely now to do more than 51 sites.

    So much for Rabbit's ears or a pocket TV anywhere :D


  • #4
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    Odd that theyre building new relays in places which have managed without them up to now while abandoning relays in areas where theyre actually needed


  • #5
    Sam Russell
    Moderators, Science, Health & Environment Moderators Posts: 20,322 Mod ✭✭✭✭Sam Russell


    Mike 1972 wrote: »
    Odd that theyre building new relays in places which have managed without them up to now while abandoning relays in areas where theyre actually needed

    That, I think, was the point of the engineering tests, (if there was any point) - to check radiation paterns to see where relays were needed and where they were not.

    RTENL have done a good job, in my opinion.


  • #6
    watty
    Registered Users, Registered Users 2 Posts: 32,445 ✭✭✭✭watty


    I was looking at my 1989 BBC TX handbook
    41 TX sites in N.I.

    In 1989 they had 99.3% population coverage, defined as
    64dB relative to 1uV/m Band IV
    70dB relative to 1uV/m Band V

    Measured 10m above ground using a dipole, as field strength was defined as

    field strength in dB referenced to 1uV/m =
    Measured V(dBuV) - aerial Gain + effective length + termination loss + cable loss

    In practical terms coverage is: a "normal" not "fringe" aerial of correct group, mounted at roof top with no noticiable noise ("snow"), reflections ("ghosts") or interference ("patterning").

    By this criteria the existing RTE coverage is nothing like claimed and the claims for coverage of the proposed 51 DTT sites seems unlikely to be 97%, more like 95%. More power doesn't help generally.

    Some existing relay sites were chosen on ESB availability or VHF coverage rather than DTT UHF coverage, so not surprising there are location changes.



    Channel five was never envisaged to be terrestrial, that was a late change of plan, which is why it uniquely was on 19.2E Analogue.


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