Do you just have basic/extended basic, or digital cable on Suddenlink and receive the HD locals? I used to be able to pick up all the HD locals with just the basic subscription, but they keep relocating every few days (always in the high digital range, channels 68.x and up... last found on 704.0, 705.0, etc.) Now all I can find is KRBCDT on 11.1, KTABDT on 11.2, and KTXSDT and KXVADT are nowhere to be found in Sweetwater.
It may be a situation where they are trying to relocate the locals to the lower numbers, but it seems odd that they only moved two of the four and the others are gone.
(I did find KERAHD on 90.1 as you suggested, relocated from 87.1, thanks for that information.)