Yes, good point on the receiver setting to 1080i. Takes some of the variability out of the equation. I think we've all seen HDTVs, even sets that are good on HD programs, do a terrible job of upconversion. (My cheap Sylvania 32" comes to mind.)
I claim Rush is a Rainbow Media channel broadcast overseas and fomerly part of the
Voom package no longer on Dish. I don't think you'll find Rush on the air or cable or satellite anywhere in America, and certainly not on Dish network. Since I didn't upgrade to HD before Voom was gone, I can only imagine the quality. But I hear it was quite good.
I'll have another look at Disney HD (looking for crappy SD upconverts?) but I don't recall the HD programs in the morning looking bad at all.
People talk about the "cliff effect" and digital being all or nothing, but in fact it is not.
(You are correct! The "cliff effect" describes a very small portion of the graph of the BER curve. The digital cliff is actually in the form of a "waterfall". I am currently changing orientation and marking up one of these BER graphs to show where we all stand...http://www.aero.org/publications/crosslink/winter2002/images/04_side1_02.gif
I am not saying "20% loss" at all; interesting error compensation techniques are employed when we get a signal, but the bit error rate is higher than the rate at which the errors can be corrected completely. All the good/bad picture degradation happens in a relatively small range of signal strength
I think...(Right again! Small increases in signal strength create large reductions in BER. The reverse is also true, meaning that small decreases in signal strength make large increases in BER.) But
any component could cause this, and the signal stength could actually be too high (such as with my channel 24 which is 2.5 miles away).
(That counts only for OTA. With the current "standard" satellite equipment, you will never achieve near the amount of signal for linearity(pixelation/signal loss) to occur.) Anything that causes the BER to go up in the range where compensation is possible
can cause visible degradation in PQ short of freezing all (or part of) the picture.
(Right again. Since 2006, I have studied, researched, and observed low signal digital television. Daily, I have watched marginal signal in my home. I even took the amplifier back off my Dad's antenna (they're always on Dish) so that I could watch the effects of marginal signal on his HDTV's when I visit. Guess what...there are more artifacts with digital than with analog!
CAN CAUSE is subject to two criteria.
1. The viewer's perception.
You first have to have eyes to see. If you haven't ever regarded the differing picture qualities between sets/systems, or you aren't searching for better quality, then you probably wouldn't even see it.
2. What part of the information is getting corrupted or lost? (I'm talking OTA, for now...)
A. You could see nothing at all wrong with the picture. (But if you turned on the closed captioning, you might see jumbled and mispelled words.) Closed captioning information corrupted.
B. If you left your HDTV on Auto format (as my Dad will attest) your picture can "scale" in size on your TV. Meaning the TV picture will go from say, full screen to postage stamp, during a program or commercial, and the format won't change it. (Satellite receivers do not use Spatial scaling, but I believe most, if not all, TV's and converter boxes do use spatial scaling.)
C. You could have lip sync problems. Timing information corrupted.
D. You could see a lower resolution picture. Video packets corrupted.
E. The brightness of the picture may vary.
It depends on what information gets corrupted or lost and how much gets corrupted, as to the resulting picture quality or plain old system performance.
Now if I'm looking at a particular degraded digital picture, I don't necessarily know if it's error compensation I'm seeing, or the operation of a statistical multiplexer, or overcompression, or a crappy conversion, or an awful source to begin with. Several of these problems can produce the same effect.
(Yes) But, based on my knowledge of what each step in the process does, and while watching my error rate meter (they raraely show signal strength these days), my best guess is that sometimes I'm seeing error compensation part of the time, and not the other causes. But I also didn't give up and accept crappy PQ, or ignore the "signal strength" mete, as others in this thread have suggested.
(Found the truth!) I kept at it, peaking my dish, changing components, and in particular for OTA broadcasts, fiddling with my antenna position and orientation and amplification for many hours over the course of a couple of months, until I have good "signal strength" on all channels we want. And I almost never see these effects.
(BINGO!) Had a big thunderstorm go through last night and I was quite amazed at how well the picture from Dish stayed perfect.