The ones I've looked at (Octagon OSLO & SMW WDL-E) fall off a cliff at around 13GHz. I'm using an SMW 12.25-12.75 with an 11.3GHz LO. The gain is around 25dB down but the NF is usable at around 2.5dB with small mods. If you wanted to drive a standard DVB tuner you'd need to replace the gain but filter out <12.75GHz as it will overload if you point at a normal satellite.
@John They ran 13428V carrier up and down for a while earlier. I noticed that the beacon (if it is that) on 13401, went up and down with 13428 then returned to it's normal level. The beacon was about 15dB down for quite a long time. That suggests that the beacon is uplinked and not generated on the satellite.
Looks like they are testing with some mod on 13428V and 13628V. I'm not sure if it's DVB or something else. The carriers are not simultaneous with mod.