Thanks to ALL. I was just experimenting with Zip Code because I HAVE tried the "Preferred" method without satisfaction.
I have had help from a knowledgeable (TRX-1) person, but still does not receive a known (in the clear" agency. In fact, using the Preferred configuration I received other P25 agencies, but not the one nearest me. I have confirmed THAT agency is being received OK by another person!
I am getting totally frustrated with EZScan and what I am reading from others commenting on RR.
From what I've seen noted in the past, zip code programming on the Whistler scanners produces different results than on the Uniden database scanners.
For the Whistler (and GRE) scanners, inputting your zip code adds systems that are in the same county as your zip code. So you might not get agencies that are nearby, in an adjacent county, even though they should be well within range.
For the Uniden scanners, inputting your zip code and a range gives you systems where the range you set, and the range of the system, intersect. A 20 mile range in the scanner, plus a system with a 25 mile range, means that the system would be active even if it were 40 miles from your zip codes location. The location used is, apparently, the center of the zip code. How accurate the system selection will be could be influenced by how far you are from that zip's center. Also see
this, for Uniden's explanation on location usage.