I am having a problem with better scanners. Each time I upgrade my scanners my chance of finding a planet drops. I just installed the Wideband MKIII and when I went to scan for a planet my chance of finding one was 9% ??? I had a much higher % (30% when I first used it) with the EM scanner I but even when I switch back to that one now its 6%. Is there something Im missing?

The more planets you already have in your database, the lower your scan effectiveness will be. Sounds like you did a major scan blitz last time around...

As Darth says, the number of planets in your database is affecting your chances.

Reduce the number of planets by using Star Chart Purger artifacts (you'll get them randomly from artifact shipments at 1000 APs per purger) and keep increasing your scanning equipment research so you can buy better scanners. People tend to research 3 or 6 levels of scanning before trying again as scanners tend to be expensive and don't increase your chances hugely per level.