There is an Echostar slate up on 11928H/3978 . Perhaps this is the ID channel mentioned above, although there is also a Dishnet slate on 11840/26000. Found a couple Dishnet transponders (11740H, 11840V, 12060H, and 12160V, all scrambled.
Also found a transponder with IP/DVB on 12173H/17780 , and a curious transponder at 11860H/30000 , which seems to be largely un-used. Ie 99% of the signal seems to be the NULL PID. A bunch of other PIDs pop up apparently with data on them, but it's not IP/DVB format. So I'm not sure what this one is. Seems like a waste of bandwidth though.
Also, a nice strong peak at 12124, but I can't seem to lock it, so I'm not sure what it is. I'm afraid that the inability to lock may be due to my ULTRA getting it's unable to scan sickness back, because after scanning in 3 or 4 transponders, I went back and now it won't scan in what it just scanned in 10 minutes ago.

I may try scanning again later with the
Mercury.
When I tuned in one of the Dishnet channels, I looked at the NIT, and that only lists 4 Dishnet transponders on that sat, ie 11740L , 11840V , 12060L , and 12160V . Ie I can't remember, but I think this is one of those sats that is capable of transmitting both in linear and circular. THere seem to be great variance in signal strength of transponders on this sat, so perhaps some transponders are linear and some circular now. Or perhaps the NIT is in error, which wouldn't be unusual.
But in any event, it looks like Dishnet may be phasing out use of this sat (based on the Echostar slate, which seems to be asking for customers), so it's probably a good sat to keep an eye on.
Forgot to mention.... There is also the NTSC analog slate (Echostar slate, not Dishnet), at 11940. This came up very weak on my receiver. Tried to touch up the polarity, and it was almost unchanged by changing polarity. If I change polarity by close to 90 deg, then the signal goes away, but I can change it close to 30 deg either way without any noticeable change. This supports the above suspicion that some of the transponders (perhaps horizontal) may be circular polarization).