grahamlthompson - 2 hours ago »
Good news - Local is a very low power MUX transmitting local TV, you are lucky to get it as it's erp is only 10kW compared to COM 7/8 over 80kW.
The main mux use 200kW.
Around 60% strength is generally thought ideal so nothing to worry about at 55%. My loft mounted log 36 has the weakest MUX at 40% but still gives gives 100% quality and rock solid reception.
One of the advantages of a log is the excellent rejection of impulse interference so will work in noisy areas.
There were a couple of OFCOM reports back in 2012 which included analysis of the choice of broadcast modes for the local muxes. Part of that was the expected reach of the low erp.
The local muxes are broadcast using QSPK 3/4. COM 7/8 are broadcast using 256QAM 2/3. Although 3/4 isn't as robust as 2/3 the difference between QSPK and 256QAM is far more significant. Due to the deliberate choice of broadcast mode for the local multiplex the 10W cited has about the same potential audience size as the 80W for COM 7/8.
