Here's the first thing to try:
Move your scanner SLOWLY around - side to side, up and down, room to room. You may find a spot where you can hear them. Bear in mind, the wavelength at 800MHz is around 13", so there will be a peak and a null every 3.25".
For a steady signal put your scanner in manual mode and put it on 860.7375. That's a WCCCA control channel.
If you still don't hear them get a redio shack 800MHz rubber duck antenna. It will help.