So are you listening to Napa County Sheriff, Fire and EMS as shown here:
Scanner Frequencies and Radio Frequency Reference for Napa County, California (CA)
www.radioreference.com
When is the last time you checked your programming against the system to be sure nothing has changed?
Now I do not have a Uniden BCD996P2 scanner so I cannot speak to that.
For the "Larson Tri Band NMO Antenna," do you know what the model number is?
When you say "Even near their mane Transmitter the Signal is Scratchy and weak!" How many miles is "near" and which received frequency(ies) are we specifically talking about? What is the terrain like between your vehicle and their main transmitter site when the signal is scratchy? Is it flat, rolling, mountainous, etc.? Would you say it was Line Of Sight (LOS) from your vehicle's antenna to the main transmitter site's antennas?
Hopefully we will have some Uniden BCD996P2 scanner owners join us here as well as some folks from the Napa County, CA area. If we cannot get some Napa County, CA scanner users to join us, you should ask the moderators to move this thread to the California forum for more focused participation.