As you have not yet used Sentinel, probably a large part of your problem is that the database that was in the scanner when shipped is likely well out of date. On the scanner itself, press the
Menu key (lower key on the left side).
At the
Main Menu on the scanner, scroll down and highlight
Manage Full Database. Press the
E (yes/enter) key to select.
At the database menu page, scroll down to
Information and select that by pressing the
E again.
That will show you the date of the main database that is on your scanner.
See this article from ScannerMaster's site:
Mac Users of Police Scanner Radios | ScannerMaster.com
If you do not want to use one of the methods indicated in the artcle, then you may want o look into getting a cheap, older, desktop or laptop to use for programming. The Sentinel software used for your scanner does not require the latest & greatest features. As long as it is running a reasonably recent version of Windows, and can connect to the internet, it should work just fine. Alternately, if you have a friend or relative that will allow you to install Sentinel on their PC, you could at least do updates to the database, as well as any that are released for the scanner's firmware.