The bad guy hacks the LA police department's computers to prevent cops from showing up at the scene of his crimes. That may be a whacky plan, but the technical aspects seem reasonably plausible.
The way the Whiz Kids crack the case is also fairly solid, albeit with a couple mistakes. First, everybody stands around an antenna that's being used to find a location. They would most likely block the signal, or at least screw up the direction. Second, they manage to pinpoint the location of a transmitter with only one receiver. That wouldn't work, they would only be able to determine direction, but not distance. To determine the location, they need two receivers to triangulate.
The way the Whiz Kids crack the case is also fairly solid, albeit with a couple mistakes. First, everybody stands around an antenna that's being used to find a location. They would most likely block the signal, or at least screw up the direction. Second, they manage to pinpoint the location of a transmitter with only one receiver. That wouldn't work, they would only be able to determine direction, but not distance. To determine the location, they need two receivers to triangulate.