Last month I purchased the Radio Shack Pro-106 to monitor the Cleveland County Project 25 system. I have programmed my scanner with all ten frequencies list at Radio Reference. I live about one mile from the Shelby site. However I often get garbled voice transmissions with my signal indicator at full strength. This even has happened when I have drove with the scanner in town in plain sight of the tower. A gentleman at the local Radio Shack stated he is aware of this happening and suggested an external antenna despite the fact my signal indicator is full strength. Is there a specific order the frequencies need to be in or what? Any help will be greatly appreciated.