re: When will fox upgrade their HD signal?

Fox/ESPN/ABC=720p
NBC/CBS=1080i

720p, full resolution 1280x720 60 frames per second, really 59.94 for you tv tech nerds
1080i, resolution 1920x1080 but each 1080 line is split into even and odd fields so you only get half resolution for each field at 60 fields per second and when combined make a 1080 30 frame image, but can lead to zigzag lines on fast motion, but now most TVs have some sort of correction to fix this.

Also, some stations on the over the air side have bit rate issues. Some stations are packing now 2 or 3 subchannels that are robbing the bit rate. Stations are working with about a 19 mbps window to send its feeds. So depending on what mix of encoding methods variable or constant can lead to wild swings in picture quality.

Also it doesn’t help that the broadcasters are still using the MPEG2 codec from the 1990’s while most others use now MPEG 4 for satellite and even some cable transmissions. Which means that the signal could be coming in MPEG 4 from the network and then transcoded into MPEG2. (FOX is supposed to have something called a splicer that does this. The splicer would control the bit rate and increase it as necessary for sports and reduce the bit rate on the other channels but that was true a few years ago and if some stations have found ways around it). The MPEG 2 signal is then sent to the cable and satellite providers which could transcode it back into MPEG4 to reach your home (true for satellite local feeds).

So yes Virginia your signal can look like crap and the reason is above too much transcoding. Hopefully, this all changes once ASTC 3.0 rolls out and 4K broadcasts start but there is always something to screw it up.