I got a bunch of VHF units which all showed as 148-174 and programmed up fine and work relatively well, and I got 'em cheap!

Recently I posted about a receive sensitivity issue with one unit. However, when I checked all of them, they all are not as hot as my regular VHF Saber. The standard Saber is red-hot receiver wise. I have no access to test equipment, just done with each radio on one of the weaker wx channels. Not a good check but adequate to tell me something is amiss.
I use these for railroad monitoring so sens is very important when I'm trying to pick up a 5W detector miles down the line when I'm out photographing trains. (For those that would say 'use a scanner,' forget it. Junk. Won't even discuss that.)
What are your thoughts on this? Indigenous to the Systems and just the way it is or something else?
OT: If you wanna see some of my photos, check here: http://www.railpictures.net/showphotos.php?userid=4208
Thanks,
Rich