Welcome to SatelliteGuys!
If it is bouncing around like that something is wrong somewhere. In my experience with the 1200 it will show around 07% signal with nothing even attached. Once it has a good connection with a working LNB(f) it goes to 50-80%. So really all that the
strength is good for is to make sure you have a proper LNB(f) attached and good coaxial connection. It should be steady though. Once a proper transponder is detected then your quality will show a number.
What kind of signal meter are you using? If you are using one of those low priced around $20 small meter with a needle that relies on power from the receiver, those will show a signal as long as it is pointing at a satellite. They can also read false positives if the dish is pointed near a faulty power line transformer or a wifi signal or a WISP.
Make sure that you have the receiver programmed with a known good transponder for the satellite that you are trying to hit. Put it on that freq. in the setup menu and slowly move your dish till you hit it. Also make sure that you have the LNBF skewed properly.
www.dishpointer.com can help you set the proper angles on your dish and skew for the lnbf. Then you can go to "The List" at the top of this page or
www.sathint.com and look up the satellite you are going for and a transponder list.
We know you have a 1200 what kind of dish and lnbf do you have? What satellite and programming are you aiming for?
Check those coax connections!