Those frequencies listed for Will County are conventional P25 and analog. You can program these frequencies from Sentinel.
Your dealing with conventional digital P25 and analog. Remember there are numerous types of digital two radio systems, P25, DMR, NXDN to name a few. There is also analog systems in use. If you see NAC it is likely a conventional P25. If you see DPL, PL it is analog conventional.
There are different radio frequency bands which which are used in various radio systems.
You can use the zip code for your residential area to program your SDS100. Using the Zip code method should help you start receiving local radio traffic.
As you become more familiar with radio systems and programming you can add more favorites list to fine tune your listening.
Another option might be a forum member sending you a file to down load to your SDS100.
Current radio hardware is complicated and inter-wined. There is a significant learning curve.
You can do a search internet searches for explanations of the different types of systems like DMR or NXDN to gain familiarity.
I have already entered my zip but it finds way too much and takes too long to scan, I end up missing a lot.
I do need to figure out what I can program manually and what is better programmed pulling from a DB.
It just seems that what I'm finding on the forums and what I'm trying to do aren't matching up 100% and I'm sure there are various reasons for that.
Thanks.