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  • A "what if" question about co-channel interference on DVB-T2

    From NY@21:1/5 to All on Fri May 2 21:27:14 2025
    Very occasionally, when the tropospheric fairy is feeling evil, our TV reception from Belmont is affected by co-channel interference from
    Crystal Palace - they are on very nearly the same bearing from us but CP
    is a lot further beyond Belmont and so a lot weaker. Sod's Law says that Belmont and CP share the same frequencies for all the muxes.

    This set me wondering... Would the effect on the received bitstream be
    any better or worse if it was the *same* mux from both transmitters on a
    given frequency, compared with if a given frequency carried two
    different muxes?

    The latter is actually the case for all six frequencies, and I wondered
    whether this was pure chance or whether the frequency allocation is done
    so that in the unlikely event of co-channel interference, it is always
    two different muxes rather than the same mux.

    I realise that many muxes have different data from different
    transmitters (different regional variations of local news, statistically multiplexed differently), but I believe all the COM multiplexes are
    identical data from all transmitters so there is a single-frequency
    network effect if you receive a strong and weak/delayed version of a mux.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Mark Carver@21:1/5 to All on Mon May 5 14:01:13 2025
    On 02/05/2025 21:27, NY wrote:
    Very occasionally, when the tropospheric fairy is feeling evil, our TV reception from Belmont is affected by co-channel interference from
    Crystal Palace - they are on very nearly the same bearing from us but CP
    is a lot further beyond Belmont and so a lot weaker. Sod's Law says that Belmont and CP share the same frequencies for all the muxes.

    This set me wondering... Would the effect on the received bitstream be
    any better or worse if it was the *same* mux from both transmitters on a given frequency, compared with if a given frequency carried two
    different muxes?

    Makes no odds, the distant transmission is miles and miles (literally)
    outside of the guard band, so the effect would be no different to two
    totally different muxes.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)