Any satellite receiver since the 1980s would be looking for the LNB output frequencies of 950-1450MHz (assuming it was used for C band). Analog satellite video was actually frequency modulated, not vestigial sideband. Digital satellite video uses several different modulation schemes, QAM, QPSK or something similar. Note that the output of the LNB is inverted.
I don't know much about Ka and Ku receivers, but they are similar in that they look at downconverted frequency bands, and almost exclusively use digital modulation. Re-reading your post, they are all direct broadcast satellite (DBS) systems, on Ku band using digital modulation. You might be able to get something out but not really worth the trouble.
looking at this page: http://www.setileague.org/articles/protectd.htm
it looks like modifying an LNB would be a better use of your time. But it might be even better to look at receiving 1420.406 MHz and looking for Hydrogen just to see what you get.