It's hard to ever be certain of copying Mandarin, Cantonese, or Tibetan language broadcasts that originate outside of China because of their relentless jamming, which is almost always China National Radio 1 (CNR1) at very high power and possibly being relayed from multiple transmitters, especially against stations like RFA. If you don't speak these languages, I suggest checking for listings of CNR1 (either standalone proper transmissions, or against other stations like Radio Taiwan Int'l) to see if the audio matches or clashes. And in the case of RFA and some others, you can also look for the live stream online to compare the program. For example, you say that it sounds like the same program on both frequencies even though they're supposed to be in different languages. They're likely CNR1.