8kW/10kW raised to 200kW on all muxes at Sutton Coldfield, only problem is it was 7th September and 21st September 2011 NOT 2012
Precisely. Until DSO - and the boosting of SC's muxes - I couldn't get a reliable Freeview signal at all. It would work at some time but not others - so I didn't bother to buy a PVR until after DSO.
The four months to which I referred is just that. Everything worked just fine from September 2011 until December 2012 - (now just over) 4 months ago.
HOWEVER, I BELIEVE THAT IHAVE NOW IDENTIFIED AND FIXED THE PROBLEM!
As a result of various people's suggestions - for which I am most grateful - I went through all the components in the "supply chain" from aerial to Humax with a fine-tooth comb. The breakthrough occurred when I by-passed the Wickes (Labgear) distribution amp. Although the signal level fell, the signal QUALITY was restored to a rock-steady 100% on all muxes. I've now installed an alternative amplifier on just the feed to the Humax (and its connected TV) and everything seems fine.
So it appears that what changed 4 months ago was that the distribution amp started generating some noise which the Humax didn't like, but which didn't upset my Philips TV. [I've no idea what might cause it to do this - maybe a dodgy capacitor in its power supply, or something? It had previosuly worked for upwards of 30 years without a problem, and is STILL working - except that the Humax doesn't seem to like its output!]
I also don't really understand why something like that would affect just the Humax and not the TV. I suppose that since the Humax's tuner can handle HD signals while the TV can't, this may possibly make it more susceptible to certain types of noise - I don't know. If that were the case, I would have expected the HD mux to be the first one to give up - but that was fine, and it was COM5 and COM6 which were troublesome.
Anyway, a very big thankyou to all who have contributed to this thread!
WT