Did you blind scan the transponders into the
Mercury, or just put in freq/SR values that you know to be correct?
I have noticed that the signal/quality meters on the Mercury are all messed up {in fact as first reported by someone else, in some menus the meter goes away completely}, but haven't really noticed it being less sensitive, in terms of being able to lock something on one, and not on the other.
What I HAVE noticed, however, is that the Mercury is VERY innacurate with respect to the frequencies it scans in. I don't think this means that the internal oscillators are off freq, because sometimes it comes up with the right freq. I think it's just a poorly written program that searches for freqs and SR values. The SR values are off far enough to make some receivers not even lock onto the transponders, however I think that the Mercury would still lock, but it's uncertain how well.
Ie how well these receivers work when they are told to tune something off freq or off SR seems very variable. My
Twinhan is VERY TIGHT, meaning that if either the freq or SR is off by even a very small amount, it will not lock at all. My Fortec Lifetime is a bit looser, in that if the SR is off by say 10 in 20,000 {ie set to 20000 when it should be 20010}, that it will lock, but it will periodically break up. However, my Fortec Ultra is LOOSE, ie I've seen it lock fine on transponders when the SR was off by 2,000 in 20,000 {ie set to 22000 when it should be 20000}. Since the Ultra and Mercury are both blind scan receivers, I'm guessing that the Mercury should be similar to the Ultra, but maybe not.
But to make a long story short, you might try changing the frequency/SR values to see what happens. Anyway, I'm VERY satisfied with the Mercury with respect to video quality, but I"m very unhappy with it with respect to the firmware. It has numerous bugs, that another forum member reported to them, but I haven't seen any indication that Fortec has fixed. One bug involves DiseqC 1.2 positioner control, but if you're using it on a fixed dish, this shouldn't affect you. But the biggest bug, is the darn meter, which just seems to dissappear at times. If I go into the DiseqC-1.2 window to fine tune a satellite, the meter will often be there initially, but as soon as I hit the bump E/W button, the meter dissappears, so I have to back out of that window, and check in another window to see if I've improved the reception, then go back to the DiseqC-1.2 to continue fine tuning. Really annoying. I think I'm going to slave another receiver to the Mercury purely for the purpose of seeing a signal meter.