How to thread?
Anyway-
It hard to trouble stuff like this on-line but here's some stuff to look for:
The dish itself:
Obstructions? Anything between the dish and the LNB (s)? I've seen cobwebs, leaves, dirt, grime all cause problems. Plus you need a clear line of sight from the dish to the Sat. Tress? Some trees that are bare in the late fall and winter are full of leaves in the spring and summer. Also look above the dish, the signal actual comes in at a much higher angle then most people realize. I've seen people install the dish beneath eves and or deck thinking the dish is pointed at the sat, it's not the signal in a bounces off the curve of the dish and hits the LNb (s?). First make absolutely sure the dish is mounted on a level, completely in all direction, mast or pole. If the mast is not level it's nearly impossible to tune in a multi sat system. Then double check and make sure the dish is actually pointed in the right direction and the skew (tilt) is correct. You can go to the direct-tv web site and enter your zip code and get instructions as to what angle, elevation, azimuth and skew you need. For about $30 at Radio Shack (if they don't have one try a local RV store) you can buy one of these:
This allows you to easily tune your dish from the dish itself and not have to rely on the signal meter at the receiver. It comes with very simple instructions. Be sure not to drop it. Drop it from almost any distance and you have to replace it, it's sensitive.
The cable itself:
First you really need RG-6 to carry a strong singal, esp if you're doing it over any significant length. A lot old buildings that converted to Sat from Cable have RG-59. It's a smaller wire and doesn't carry the signal well. Your cable should say RG-6 or RG-59 right on the side somewhere. Check the connections at the LNB and at the back of the receiver. Disconnect the cable and examine it. You don't want it loose and you don't want to see any of the outside wire (shielding wire) poking through the end connection and making any contact with the copper center wire. This will kill your signal strength. And you want that center copper wire sticking out flat with the end of the connection, if you can't see the center copper wire you'll need to cut off the end, strip the wire back and crimp a new connector in place. If you have to replace cable end get a real crimper, 20 bucks will get you this at any radio shack:
(sorry for the picture quality it's late, I'm tried)
Good solid and tight connections are very important to getting the max signal to your receiver. You can use a pair of standard pilers, but the crimpers are worth the price, IMHO.
Another thing to look for is any area of the cable that has been wrapped around, or "looped." A large pile or bundle of cable will actually interfere with itself. also if it runs over or directly next to a 110w power outlet the signal can be seriously effected.
Lastly, for now, you say your whole building has access to this/these dishes? If it's one dish you have splitter or "switch" somewhere in between your receiver and the dish, be sure to check the connection there as well.
I've done about 250 of these over the years, probably 20 since I moved to Mexico. The farther south you go the harder it is to find a signal.
If you have any questions feel free to ask, I'll try to keep an eye on this thread- or PM me.