OK.. see if you can answer this question. I dont know much about translator rules. Could KSIL (if they had a hd2 Could they feed another translator in the el paso market that is not a fill in translator?
First, KSIL and K232FC (the translator at 94.3 in El Paso), are not owned by the same people, at least according to the documents I was able to find on the FCC website. Commercial non fill-in translators are legal provided they are not co-owned and that they capture the signal they're relaying over-the-air. I believe, as PT Board Op mentions, the owner of the translator is not allowed to be paid by the parent station to carry its signal either. Remember, just because you can't get KSIL off-air when driving around El Paso doesn't mean it's not possible for the translator to receive it. That translator would appear to be on top of a mountain, and that location can likely receive signals you can't receive at ground level.
Second, far as I know, the law doesn't prohibit relaying an HD2 signal on a commercial non fill-in translator. So, KSIL could feed another translator in the El Paso market so long as that hypothetical translator meets all required conditions, including not being co-owned with the parent signal and picking up the signal off-air. Not to say that none exist, but I'm not aware of any commercial non fill-in translators relaying a digital signal, though, probably at least partly because pure digital signals aren't generally known for their reliability. HD digital signals are typically more difficult to pick up off-air at a distance and tend to have more frequent drop-outs the farther away from the transmitter. The multicast channels, of course, also have an added obstacle in that they don't have an analog signal to fall back on when they drop out; when they're gone, they're just gone.
Finally, the way you would know if a translator is a fill-in or non fill-in service is by the signal contour of the parent station. If the translator's signal lies wholly inside the parent station's primary signal contour, it's a fill-in translator. If it lies partially or completely outside the parent station's primary signal contour, it's a non-fill-in translator.