Thanks for the info did not know this, also what should I use for my range you stated less then 20 ? thanks again for the info.
That is something you'd need to decide for yourself and can vary from place to place....
Something to understand about locational type programming is that is uses whatever the RR database admins and submitters of information opted to use for location and range.
For the most part, every system, site, and group of users (Uniden calls "departments") has a LAT, LON, and RANGE assigned. These values may or may not be correct. They also could be HUGE (hundreds of miles) or TINY (as small as 1/2 mile). In some cases, the (bad) location data places systems, etc. in Tibet, China, etc due to missing characters..... In other cases, the location data is just wrong (I've personally submitted numerous updates as I find these issues).
If you can, picture all of these LAT/LON points and RANGE circles as rings on a map.
Now, your location (zip code or otherwise) and "range" setting also essentially resolves to a point and a circle around it on a map.
For locational programming, everything/anything in the database with a "circle" that overlaps with "your circle" will be loaded and scanned (except for items with those service types you've disabled and/or items that you've locked out).
With large range settings you are obviously going to have the radio trying to scan a whole lot more stuff than is likely to be in reception range. Some of this can include items that might be in the next state (or in some cases even beyond) because of the large "circle" required to cover some areas on a map (i.e. if the jurisdiction is "wide" or "tall", etc.). I've seen some cases where the radio tries to scan Virginia and even West Virginia from my location here in southeastern North Carolina (wasteful).
Conversely, if you set the range very small (even down to 0), you'll be more likely to narrow the list of items significantly - but also potentially remove "departments" and other things that have small "circles" assigned (example, a county or state trunk system with large footprint but some "small town departments" carried on the system are set to 0.5 miles).
There's lots of Nationwide things typically included also that you may or may not want to include (but you have options to disable those).
If you really want to see what the radio will try to scan using a zip code/location and a range, there is a function in Sentinel (Edit -> Add Channels on Range) that will help you see what the radio is/will try to scan using various locations and range settings. Before running this, go into the Profile editor and enable Full Database.
Note: this
could potentially be a good starting place for building your own favorites lists (delete the stuff you don't want).
It all comes down to how much you want to learn, understand, and use to optimize performance.