No change in compression has occurred.
Do you genuinely know something from the inside of Dish Network engineering, or are you just shooting from the hip? Because none of the known facts (changed transponders, same # of HD channels) proves what you are stating with such finality. Something as simple as a different transponder
might well change the SNR on the ground for some (or all) customers, thereby messing up PQ in complicated ways. Yes, it's a digital signal, and if everybody got every bit back that was originally uplinked all the way through their receiver hardware, then everybody's picture might be the same. Otherwise, we're talking about error correction for missing bits, and this may be complete and result in a pristine picture, or might not be complete in which case you see the ghastly artifacts reported in this thread and elsewhere.
Furthermore, Dish
very well might be tweaking one or more of (how many?) parameters on their statistical multiplexers, without altering the channel count. After all, the channel count is quantized, whereas the amount of compression is not. (Well, it's quantized too, but on such a fine scale that it won't matter.) If I were a Dish Network broadcast engineer, I'd be playing with those parameters all the time. This would of course be in preparation for
increasing the channel count/transponder further. That is my guess as to why so many have reported this erosion of HD PQ over time.
Isn't there a PQ email address to report problems like this? If all we do is bitch/moan about macroblocking, green squares, fuzziness, and lousy lip sync
here on Satelliteguys.us, then you can be assured the PQ will only go down over time.